From early childhood to later stages of life, many dental patients experience a variety of treatments, ranging from basic fillings for cavities, to more complex procedures like crowns and bridges. Throughout their lives, they may also require specialized care from endodontists, orthodontists, or periodontists to maintain their oral health as they age. With an average lifespan of 77.5 years for both sexes,¹ and the percentage of older adults retaining their natural teeth on the rise,² the dental profession in the United States is seeing an older patient population presenting for treatment who have retained most, if not all, of their natural dentition. 

However, as one of the most mobile countries in the world,³ these patients have been treated by a variety of dental professionals as they relocate from one locale to the next. Whether moving to upsize or downsize their homes, change jobs, or retire to a warmer climate, it is estimated that the average American moves 11.7 times in his or her lifetime.⁴ Moving to a larger city or across state lines necessitates finding a new dentist to meet his or her prevention and treatment needs. Other issues impacting the move to a new practice may be dissatisfaction with treatment results, the retirement of the primary care dentist, or high out-of-pocket expenses. For older adults in particular, the result can be a patchwork of dentistry performed to address immediate needs, which, over a lifetime, have lost the continuity and history of previous treatment goals.

In the case presented here, an older patient in good health presented to the practice with aesthetic concerns and had all but given up on addressing her primary complaint of jaw pain after a variety of treatment modalities meant to treat it had failed.   

CASE REPORT

A 68-year-old female was referred to the practice by her husband (Figure 1). At her initial consultation, the patient recounted her dental history of orthodontic and prosthodontic treatment to relieve her TMJ pain and address aesthetic concerns. Her TMJ issues had plagued her since the age of 27 and still persisted, making her skeptical that any treatment would be successful. She was also concerned about the chipping occurring on her 2 natural central incisors (Figure 2). 

Figure 1. Preoperative photo of the patient revealing her gummy smile and lack of gingival harmony.

Figure 2. Close-up view of the anterior teeth revealed chipping on the central incisors.

A series of x-rays were taken to ensure the structural soundness and health of the patient’s teeth, gums, and bone. Preoperative photos of the maxillary arch documented that teeth Nos. 4 and 5 had been restored with crowns; No. 7 was a crown over a 30-year-old titanium implant; and Nos. 2, 3, 14, and 15 had undergone root canal treatment (Figure 3). Kois glasses also revealed a slight midline discrepancy, which would also need to be addressed (Figure 4).

Figure 3. X-rays and pre-op photos of the maxillary arch documented that teeth Nos. 4 and 5 had been restored with crowns; No. 7 was a crown over a 30-year-old titanium implant; and teeth Nos. 2, 3, 14, and 15 had undergone root canal treatment.

Figure 4. Kois glasses revealed her midline alignment would need to be addressed.

On the mandibular arch teeth, Nos. 23 to 26 had been treated with veneers, No. 19 was a crown, Nos. 20 to 22 and 27 to 29 were porcelain bridges, and natural teeth Nos. 30 and 31 were both restored with large composite fillings (Figure 5). Severe pitting on tooth No. 30 along the buccal cusp was noted, along with wear on the cusps of the other mandibular molars and crack lines on her 2 anterior central incisors (Figure 6). The patient exhibited a VDO of only 32 mm with evidence of a collapsed bite. She had a wide gummy smile (Figure 7) with poor gingival symmetry of the anterior arch.  

Figure 5. Pre-op view of the mandibular arch teeth showed that teeth Nos. 23 to 26 had been treated with veneers, No. 19 was a crown, Nos. 20 to 22 and 27 to 29 were porcelain bridges, and natural teeth Nos. 30 and 31 had both been restored with large composite fillings.

Figure 6. Although not an immediate problem, crack lines in the central incisors could cause issues in the future.

Figure 7. The patient exhibited a VDO of only 32 mm with evidence of a collapsed bite, a wide gummy smile, and poor gingival symmetry.

Treatment Proposal

In order to restore proper function and aesthetics for this patient, the first step in the treatment plan was to address her TMJ pain. To determine if a Kois Deprogrammer would be a viable treatment, load (joint) and immobility (muscle) tests were conducted and were deemed negative, indicating a Kois device would be an appropriate treatment strategy.^5-9 A Kois Deprogrammer was prescribed to restore her occlusal and temporomandibular stability and open her VDO to create restorative space for a full-mouth rehabilitation. The goal was to open her bite 1.5 mm in the posterior and restore her upper arch with crowns on teeth Nos. 2 to 15 and then, at a later appointment, restore her lower arch. A leaf gauge was used to determine centric relation. Intraoral scans of both arches (Figure 8), a bite registration, and pre-op photos were sent to the laboratory for fabrication of a Kois Deprogrammer. At the second appointment, the deprogramming device was fitted, and the patient was instructed to wear it 24 hours per day for 2 weeks except when eating.

Figure 8. After testing load and mobility tests of her jaw, a Kois Deprogrammer was prescribed to relieve her TMJ pain. Intraoral scans of both arches, a bite registration, and pre-op photos were sent to the laboratory for fabrication of a Kois Deprogrammer.

Two weeks later, the patient reported that she was free from pain and that she could now open to 45 mm. Scans of both arches of the deprogrammed jaw and a bite relation photo (Figure 9) were taken and sent to the laboratory for fabrication of a diagnostic wax-up and a putty matrix for provisionalization.

Figure 9. Post-deprogramming scans of both arches and a bite relation photo were sent to the laboratory for fabrication of a diagnostic wax-up and a putty matrix for provisionalization.

Restorative Treatment

The patient’s excessive gum display was addressed on the fourth appointment in order to achieve the desired aesthetic outcome.¹⁰ In this case, gum recession on the implant tooth No. 7 guided the crown-lengthening surgery performed on teeth Nos. 4 to 13. All paper records of the 30-year-old implant had been purged, leaving no option but to prep it for a crown with no knowledge of the implant system used and to mask the metallic substructure as best as possible. 

Figures 10 to 12. Crown-lengthening surgery for this case was guided by the gum recession on implant tooth No. 7. After 6 weeks, the gums had healed nicely.

When the patient returned 6 weeks later, the gums had healed nicely (Figures 10 to 12). The crowns on teeth Nos. 2 to 5, 7, 14, and 15 were removed and examined for underlying decay, and all teeth in the upper arch were prepared to receive all-ceramic crowns (Figure 13). Photos of the prepared patient with the stump shade were taken (Figure 14) for communication with the laboratory. 

Figure 13. The upper arch was prepared for all-ceramic pressed crowns on teeth Nos. 2 to 15.

Figure 14. A photo of the stump shade was taken to communicate with the laboratory. The key to restorative success would be masking the titanium abutment on tooth No. 7.

Figures 15 to 17. The upper arch was provisionalized, and the patient was instructed to wear the provisionals for a month to test fit, function, and aesthetics.

Using the putty matrix supplied by the laboratory, provisionals (Structur 2 SC Self Cure [VOCO]) were fabricated for both arches chairside and spot-etched and bonded in place (Adhese [Ivoclar]) (Figures 15 to 17). For the mandibular arch, all existing restorations were removed, and the teeth were provisionalized without prepping to ensure the patient functioned well with her new centric relation. The patient approved the aesthetics of the provisionals and was advised to wear them for one month to test the function and fit as well as to ensure her jaw pain was no longer an issue. 

After wearing the provisionals for a month, she returned to the practice pleased with the aesthetics and functional outcome of the treatment and reported no jaw pain was present. A scan of the upper arch, along with photos with a tooth shade tab (Figure 18) and a bite stick photo were sent to the laboratory to fabricate the final restorations (IPS e.max Press shade M1 [Ivoclar]).

Figure 18. A photo of the provisionals with a shade tab was taken to communicate with the laboratory.

Figures 19 to 22. The final maxillary restorations were delivered and seated.

On delivery, the final restorations for the maxillary arch were seated (Variolink Esthetic DC Neutral [Ivoclar]) (Figures 19 to 22). The following day, the teeth in the mandibular arch were prepared and provisionalized. Upon delivery, the final mandibular restorations were seated (Variolink Esthetic DC for crowns and Variolink Esthetic LC Neutral for veneers [Ivoclar]), and the patient was pleased with the final outcome. A month later, she returned for a follow-up appointment, and final photos were taken of the case outcome (Figure 23).

Figure 23. Three weeks after the final mandibular restorations were seated, the patient returned to the practice for final photographs.

CONCLUSION

Often, patients present to the practice disappointed by past dental work and have lost faith and trust in the profession in treating long-standing problems. Taking them to the point of accepting treatment involves rebuilding that trust and helping them overcome their fear of the process. Approaching these patients with concern and compassion and focusing on relieving long-standing issues before rehabilitating the aesthetics of their smiles can restore that trust and belief in the profession.

The patient’s reaction sums up the outcome of this case: “No doubt my case brought with it obstacles and challenges. As a patient, coming to the decision of going forward with a full restoration is actually a big decision. Turning oneself over to the process involves trust and letting go of fear. I came to you to change, improve, and restore my smile. You did that and far more by providing me with a professional, all-encompassing plan of action to correct and restore long-standing problems. I remain grateful and appreciative. Thank you kindly.”

ACKOWLEDGMENTS

Dr. Desai would like to thank ceramist, Juan Rego, from Smile Designs by Rego (regosmiles.com) for the collaboration and ceramic work. 

REFERENCES

1. Kochanek KD, Murphy SL, Xu J, et al. Mortality in the United States, 2022. NCHS Data Brief. 2022;(492):1-8.

2. Centers for Disease Control and Prevention. Oral Health Surveillance Report: Trends in Dental Caries and Sealants, Tooth Retention, and Edentulism, United States, 1999–2004 to 2011–2016. Atlanta, GA: Centers for Disease Control and Prevention, US Dept of Health and Human Services; 2019. 

3. Plumer B. Americans still move around more than anyone else in the world. Washington Post. May 15, 2013. 

4. Chandler A. Why do Americans move so much more than Europeans? Atlantic Monthly. October 21, 2016. 

5. Gaikwad A. Effects of different deprogramming devices on electromyographic activity of masseter and temporalis muscles: A crossover clinical study. J Indian Prosthodont Soc. 2020;20(Suppl 1):S9-S10. doi:10.4103/0972-4052.306365 

6. Kois JC, Hartrick N. Functional occlusion: Science-driven management. J Cosmet Dent. 2007;23(3):54–7. 

7. Jayne D. A deprogrammer for occlusal analysis and simplified accurate case mounting. J Cosmet Dent. 2006;21(4):96-102. 

8. Beshar MJ. Systematic treatment using a direct deprogrammer to resolve long-standing problems in a phobic patient. Compend Contin Educ Dent. 2015;36(6):418, 421–5. 

9. Ohyama H, Nagai S, Tokutomi H, et al. Recreating an esthetic smile: a multidisciplinary approach. Int J Periodontics Restor Dent. 2007;27(1):61–9. 

10. Kois JC. Altering gingival levels: The restorative connection part I: Biologic variables. J Esthet Restor Dent. 1994;6(1);3-7. doi:10.1111/j.1708-8240.1994.tb00825.x

ABOUT THE AUTHOR

Dr. Desai, a graduate of the Kois Institute, holds degrees in dental hygiene and dental surgery from the University of Southern California. She is an accredited member of the American Academy of Cosmetic Dentistry, a distinction shared by only a select few globally. Dr. Desai has also been recognized as a top dentist in Orange County for the past 5 years and was named one of the Top 40 Dentists under 40 in the nation. Her contributions to the field include publications in prestigious dental journals and speaking engagements, leveraging her expertise to advance dentistry. Dr. Desai founded Luminous Smiles of Newport Beach, Calif, a boutique dental practice focused on enhancing patients’ smiles. She can be reached at drdesai@luminoussmiles.com. 

Disclosure: Dr. Desai reports no disclosures.  

Internal bleaching is a highly sought-after treatment and a great service to provide to patients. External bleaching differs from internal bleaching in the sense that external bleaching addresses superficial staining, while internal bleaching manages internal discoloration. External bleaching is generally applied to the entire dentition, but internal bleaching may only target one or a few teeth. 

There are several reasons a tooth may become internally discolored: pulp necrosis, intrapulpal hemorrhage, retention of pulp tissue at the time of root canal therapy, calcific metamorphosis, or internal resorption.¹ Other available treatment options to address discoloration include porcelain veneers and composite veneers with the use of opaquer. The advantage of internal bleaching is that it generally conserves tooth structure. Additionally, managing a discolored tooth with porcelain can present unique challenges. Teeth typically become darker as they are being prepared for a veneer. This can present a challenge to the ceramist to mask the discoloration when creating the veneer. 

Composite with opaquer is an excellent option for masking a discolored tooth; however, this treatment modality also presents with its own unique challenges due to its technique-sensitive nature. The challenge involved with using opaquer is that it raises the value of the restoration. The clinician must be very mindful not to overuse opaquer to the extent that the tooth no longer matches the surrounding dentition and the tooth looks lifeless. 

All things considered, internal bleaching also presents obstacles. The final outcome of the bleaching is not always guaranteed, and it may require multiple visits, depending on the technique utilized. Internal bleaching is, however, very safe. Historically, the “walking bleach” technique, a form of internal bleaching, was done with heated superoxol, which presented a considerably higher risk of resorption than modern sodium perborate or carbamide peroxide. 

CASE REPORT 

A 50-year-old female presented seeking treatment for a discolored No. 9. A shade-matching photo was promptly taken with a DSLR camera and macro lens (Canon 80D). VITA shade tabs were used to gauge the patient’s current tooth shade (A3.5) (Figures 1 and 2). It is important that the photo is taken quickly and before the tooth dehydrates. The value of a tooth is artificially raised as it becomes dehydrated. This may lead to an incorrect color match. Gathering the initial shade is helpful for tracking the progress of the bleaching therapy. A patient may feel that the bleaching has been unsuccessful but may gain new faith in the process when he or she sees before and after photos. 

Figures 1 and 2. The initial presentation of No. 9.

It is vital for the clinician to determine the pulpal diagnosis prior to bleaching or restorative treatment. This may determine the treatment option the patient is best suited for. In the event the tooth still remains vital, the clinician may consider using a restoration to mask the dark tooth. Internal bleaching requires RCT, which some patients may not be amenable to. Additionally, in the event RCT has been previously completed, it needs to be determined whether or not the existing RCT is acceptable. The clinician should evaluate the fill, taper, and density of the obturation. In the event the previous treatment is not satisfactory, it should be re-treated prior to the completion of internal bleaching. Finally, a periapical diagnosis of the tooth should be determined prior to treatment. Although the RCT may appear acceptable, the patient may have an underlying periapical pathology (such as asymptomatic apical periodontitis or a chronic apical abscess) that should be ruled out prior to elective treatment.  

A periapical radiograph was taken and reviewed of No. 9. This tooth had a previously completed RCT with a poor fill, taper, and density (Figure 3). No. 9 responded non-tender to percussion and palpation, and all probing depths were 3 mm or less. The poor existing fill, taper, and density warranted the RCT to be re-treated. A failure to redo the RCT can be thought of as building a house on “sinking sand.” A tooth should be free of disease or pathology prior to the placement of a restoration or internal bleaching. 

Figure 3. A periapical radiograph was taken of No. 9 in order to gauge the pulpal and periapical diagnosis and assess the quality of the root canal therapy.

The patient was then presented with several treatment options, including internal bleaching, a porcelain veneer, and a composite veneer. The risks and benefits were thoroughly reviewed, and she elected for internal bleaching. 

The author completed the root canal therapy retreatment and then placed an orifice barrier with Vitrebond (3M) (Figure 4). The orifice barrier was placed at the level of the CEJ. If the orifice barrier is placed too far incisally, it will cause the cervical third of the tooth to not completely bleach. Alternative RMGIs that could have been used are GC Fuji II LC (GC) and BC Liner (Brasseler). The advantage of BC Liner is that it can come in a blue shade, which facilitates better identification of the orifice barrier in case of an RCT re-tx.

Figure 4. After RCT was completed, an orifice barrier was placed at the level of the CEJ with with an RMGI.

Next, any remaining core material was removed from the chamber under rubber dam isolation. This step is challenging but perhaps one of the most critical because it can be difficult to discern where the restorative material begins and ends. Failure to remove any core material completely will prevent the tooth from bleaching completely. If it is noticed that the internal bleaching is entirely ineffective, it may be because of the residual core build-up material. Clinicians should be particularly careful when removing the core material because it may result in a perforation of the facial tooth structure. 

Different techniques for identifying remaining restorative material include (1) scratching the material, (2) placing phosphoric etch over the composite, (3) using a black light pen, and (4) taking a radiograph. Many core materials and composites, but not all, will display a black scratch when scratched with an explorer. Phosphoric-etch placement can also be used because it alters the optical properties of the composite. An inexpensive black light pen is useful as long as the composite has additives that fluoresce; not all composites have this additive.² A periapical radiograph can also be taken if the operator is unsure if any composite remains. But even this step may be thwarted if the chamber is filled with a microfill composite, which typically lacks a radiopaque additive. In effect, it should be noted that the clinician should be prepared to utilize a range of techniques because no technique is guaranteed to be successful. In this case, the core was restored with a resin composite material that fluoresced, so a black light pen was used to remove all the composite.

Next, sodium perborate was crushed and moistened with water so that it had the consistency of wet sand. It was then placed in the chamber, and the access was sealed with Cavit (3M) (Figure 5). Alternatively, it could have been sealed with GC Fuji TRIAGE (GC), but the downside of this material is that because it bonds to tooth structure, it is more time-intensive to remove. In order for internal bleaching to be profitable for the clinician, replacing the bleach at follow-up appointments needs to be quick. The ratio of Cavit to bleach should also be weighed carefully by the practitioner. The advantage of having a thin layer of Cavit over the access is that there is more room for the bleach to be effective. But the downside is that the thin temporary material may be more likely to fall out. Neither the clinician nor the patient should be too concerned if the barrier falls out as long as a sound orifice barrier is in place.

Figure 5. After crushed sodium perborate was placed in the chamber, the chamber was sealed with Cavit (3M).

The patient was instructed not to incise on No. 9 until treatment was completed and a definitive core could be placed. The patient was reappointed for the bleach to be replaced within 7 days. Clinicians should anticipate that they will be replacing the bleach about every 5 to 10 days for about 2 to 4 appointments. 

Figure 6. A follow-up shade-matching photo was made after the 3 rounds of internal bleaching using the “walking bleach” technique with sodium perborate.

After 3 rounds of internal bleaching with sodium perborate, No. 9 failed to respond to treatment (Figure 6). All variables as to why No. 9 failed to respond to sodium perborate were ruled out. The expiration date on the material was re-verified, and a periapical radiograph was taken to ensure all composite core material had been removed. 

A second bleaching technique was employed. A rubber dam was placed over No. 9, and 40% hydrogen peroxide (Opalescence Boost PF 40% HP In-Office Power Whitener [Ultradent Products]) was placed inside the chamber and on the outside according to the manufacturer’s instructions (Figure 7). It should be noted that, per the manufacturer’s instructions for use, this material is also intended for internal, nonvital bleaching. This product was not used off-label. Once the in-office whitening was completed, the chamber was sealed with Cavit, and the tooth was given 3 days to rehydrate in order to determine the new shade. The attempted in-office bleaching also achieved a minimal increase in value (Figure 8).

Figure 7. In-office bleaching was attempted on No. 9 following the manufacturer’s instructions.

Figure 8. A follow-up photo was taken of No. 9 to gauge the progress of bleaching following the in-office treatment.

A third technique was employed to internally bleach No. 9. The “inside-outside” bleaching technique, which involves at-home external and internal bleaching, was attempted. In this technique, the orifice barrier is left intact, but the chamber is removed of any temporary materials and thus left hollow. Clinical data has demonstrated that this technique is as safe and effective as the walking bleach technique.³ Next, the patient was given a bleaching tray and instructed to fill the chamber and external surface of No. 9 with 10% carbamide peroxide (Opalescence 10%-Carbamide Peroxide [Ultradent Products]) (Figures 9 and 10). The patient was instructed to remove the bleaching tray when eating and drinking and to rinse out the chamber with water (using a Monoject syringe [Cardinal Health]) before and after eating. In order for this technique to be effective, patient compliance is paramount. The patient must ensure the chamber is free of debris before filling it with bleach. She was also carefully instructed to avoid incising on No. 9 because it was hollow and particularly brittle. Once she was done eating or drinking, she was to refill the chamber and external surface of No. 9 with the bleaching gel. The patient was then dismissed and returned 21 days later. 

Figure 9. Ten percent carbamide peroxide was placed in the chamber of No. 9.

Figure 10. The patient wore a bleaching tray with carbamide peroxide that was placed in the chamber and on the external surface of the tooth. It should be noted that No. 9 appeared translucent on the facial surface because Cavit was not cur- rently in the chamber. In previous images of No. 9, Cavit was in the chamber, which made the facial appearance of No. 9 look less translucent. The facial surface of No. 9 was translucent due to the removal of the core material.

It is the author’s opinion that case selection for the inside-outside technique is a key factor in success. Only patients who demonstrate they will be compliant should be selected. The patient is responsible for keeping the chamber clean and faithfully applying bleach. 

Following completion of the treatment, her desired outcome was finally achieved (Figure 11). The chamber was then temporarily filled with Cavit once more for 2 weeks prior to placement of the final restoration. A tooth should never be restored immediately after bleaching but rather 10 to 14 days later.⁴ After 14 days, the chamber of No. 9 was restored with a bleach shade resin composite under rubber dam isolation. Restoring the chamber with a bleach shade composite is an important final step for success in achieving patient satisfaction.

Figure 11. The final postoperative photo of No. 9 after the completion of bleaching.

The hypothesized reason as to why the inside-outside technique achieved a favorable outcome over the other techniques is that No. 9 was continuously being exposed to fresh bleach for a lengthy period of time. The downside of using sodium perborate in the walking bleach technique is that the efficacy of the material decreases over time. Although the in-office technique utilizing 40% hydrogen peroxide involved a high concentration of bleach, the tooth may not have been exposed to the bleach for enough time.

ACKNOWLEDGMENT

Special thanks to Dr. Jason Smithson for introducing me to this technique.

REFERENCES

1. Hattab FN, Qudeimat MA, al-Rimawi HS. Dental discoloration: an overview. J Esthet Dent. 1999;11(6):291-310. doi:10.1111/j.1708-8240.1999.tb00413.x 

2. Brauer, J. The scorpion technique: a veneer-seating pearl. Dent Today. 2024;43(1):97-99.

3. Pedrollo Lise D, Siedschlag G, Bernardon JK, et al. Randomized clinical trial of 2 nonvital tooth bleaching techniques: A 1-year follow-up. J Prosthet Dent. 2018;119(1):53–9. doi:10.1016/j.prosdent.2017.03.004

4. Attin T, Hannig C, Wiegand A, et al. Effect of bleaching on restorative materials and restorations—a systematic review. Dent Mater. 2004;20(9):852–61. doi:10.1016/j.dental.2004.04.002 

ABOUT THE AUTHOR

Dr. Seibert is the deputy program director for the AEGD residency at Langley Air Force Base in Virginia and a clinical instructor at the University of Creighton School of Dentistry. She is the creator and host of the Dental Digest podcast, a podcast in the top 1% of all podcasts globally. She lectures to national and international audiences and has multiple publications related to clinical dentistry. She was recently named a top 40 under 40 dentist in America by Incisal Edge magazine. She can be reached at dr.melissaseibert@gmail.com.

Disclosure: The views expressed are those of the authors and do not reflect the official views or policy of the US Air Force, Uniformed Services University, Department of Defense, or its components. The author does not have any financial interest in the companies whose materials are discussed in this abstract. 

Complex cases can be challenging for a variety of reasons, such as patient demands, budgetary constraints, clinical conditions, and so on. When facing cases of this type, which many dental practitioners will immediately recognize as typical, a team approach between the dental practitioner and the dental laboratory is best. Along with using basic new technologies at our disposal, the team can aid in eliminating potential challenges to achieving the desired results that satisfy the patient’s expectations and budget while decreasing the practitioner’s stress levels. 

In addition to identifying a solid lab partner to handle the case, the dental practitioner can also take advantage of the advancements in cementation, restorative materials, and dental laboratory virtual planning technology to achieve results that satisfy the patient’s expectations while avoiding the stresses that can arise from complex cases.  

In this case, a patient presented with a situation not all too unusual in dentistry—a blend of clinical issues, conditions lost to time, and high expectations to have it addressed to her specific needs and budget. In this circumstance, the choice of lab, materials, and cementation enabled a consistent and predictable workflow for the patient that mitigated stress for the practitioner, team, and patient.

SETTING THE COMPLEX CASE UP FOR SUCCESS

Choosing the Laboratory

When choosing the dental laboratory you want to work with, using virtual planning tools is critical to improve communication between the practitioner and lab so that the patient’s expressed aesthetic and functional goals can be achieved with minimal stress. The lab should also be able to furnish a provisional to “test-drive” the aesthetics and function to allow the patient to express any changes he or she may want prior to fabrication of the final prosthetics. With virtual design incorporating those changes, the lab can quickly make the requested changes and allow the practitioner to see a virtual model before the lab fabricates the restorations. Those changes may include midline placement and angulation, vertical dimension of occlusion (VDO) increases or decreases, and/or shade changes. Virtual planning capabilities with the laboratory are essential.

Prosthetic Planning Choices

Zirconia restorations are increasingly being used both with natural teeth and implants as either single units, partial arches, or full-arch prosthetics. Cementation to zirconia has, in the past, been a potential issue to achieve a good bond to the zirconia. Some routinely used cements (such as glass ionomers) have minimal, if any, real bond to the zirconia surface, and debonding becomes a potential issue over time. Resin cements have been recommended to prevent debonding and are commonly used for this application. Therefore, the selection of a resin cement with high bond strength to zirconia is important. Additionally, the use of a resin cement that has high bond strength to metal eliminates potential debonding between the cement and the abutment head.

One challenge when cementing to implant abutments vs natural teeth is a snugger fit of the prosthesis to the abutments when multiple units are being restored (partial- or full-arch restorations) than typically observed with natural tooth preparations. Thus, the utilization of resin cement with a low film thickness allows full seating of the restorations without the cement potentially preventing that seating. The author suggests, especially when cementing a restoration on an implant abutment, to not fill the interior of the abutment with cement as this may prevent full seating of the restoration due to hydraulic pressure as the cement pools at the coronal of the abutment. Placement of cement on the interior marginal area of the abutment crown permits full seating as the cement spreads coronally as the restoration is seated. 

BruxZir Dual Cure Resin Cement (Glidewell) fulfills the goals discussed. The resin cement has high bond strengths to dentin and etched enamel without the need for a separate bonding agent. Additionally, its high bond strengths to various restorative materials allow its use with metal-based restorations, metal implant abutments, various ceramics in use for restorations, and zirconia. The cement’s high compressive strength and shear bond strength allow its use for any clinical situation and crowns, bridges, and veneers that require cementation. BruxZir Dual Cure resin cement is well-suited for cementation of zirconia, helping eliminate potential debonding of the restoration from the underlying tooth or implant abutment. 

CASE REPORT

An 80-year-old female patient of the practice presented after an absence related to the pandemic and family health issues indicating several teeth had broken. The patient had previously been treated in the author’s practice with implants in the maxillary left posterior and posterior bilaterally in the mandible. The examination noted several remaining teeth had fractured (Nos. 5, 9, 10, 11, and 21), of which several had prior endodontic treatment, and the crowns had been lost. Mobility of Grade 1 was noted on teeth Nos. 22 to 26. The implant crown on No. 14 was missing. 

A panoramic radiograph was taken to evaluate the teeth and implant present (Figure 1). Evaluation of the radiograph noted recurrent decay on the crowns of teeth Nos. 7 and 27, which had prior endodontic treatment, and a periapical lesion was noted on No. 27. Those natural teeth were in poor condition and would not be restorable. Bone levels on the existing implants at Nos. 12, 14, 15, 19, 20, and 28 to 30 demonstrated no crestal bone loss. 

Figure 1. The patient presented with fractured teeth and periodontal bone loss on the remaining teeth in both arches.

The patient expressed a desire to replace the natural teeth with implants to reduce the risk of additional potential problems vs attempting to restore the remaining natural dentition. 

The patient indicated she wished to be sedated during the extractions and implant placement due to her exaggerated gag reflex. With that in mind, she would be referred to an oral surgeon who would perform the extractions and implant placement under the desired sedation. A treatment plan was formulated to place implants at sites 3, 5, 8, 9, and 11 in the maxilla and 21, 24, and 27 in the mandible. Restoration would consist of custom abutments in both arches and restoration with BruxZir monolithic cementable bridges on Nos. 3 to 11 and 21 to 27, with a single crown at No. 14. 

Impressions were taken, and provisional partial dentures were provided as the plan was not to immediately load the implants due to her age and concern about bone density. The patient was given a referral to the OMFS, and a consultation appointment with them was scheduled for her. 

The provisional partial dentures were returned from the lab. The OMFS office was notified that we had them and to have the patient scheduled with our office to insert them a few days following her implant placement appointment. The patient was treated under sedation, wherein the remaining teeth were extracted. AnyRidge implants (Mega’Gen USA) were placed as follows: No. 3: 5 × 10 mm, No. 5: 4 × 11.5 mm, No. 8: 4.5 × 11.5 mm, No. 9: 4.5 × 11.5 mm, No. 11: 4 × 11.5 mm, No. 21: 3.5 × 11.5 mm, No. 24: 3 × 10 mm, and No. 27: 4 × 11.5 mm. Cover screws were placed with primary closure over the implants being achieved.           

The patient presented 4 days following extractions and implant placement with the implants covered with soft tissue. The provisional partials were tried in, adjusted, and relined with COE-COMFORT tissue conditioner (GC). The design of the maxillary partial was with a minimal horseshoe palatal coverage due to her exaggerated gag reflex. The patient was scheduled a week later to check the provisionals. She presented for that appointment indicating she was having issues with gagging and, after a day or 2, decided not to wear the provisionals and consume a very soft diet. During a discussion with the patient, she indicated she would prefer not to wear any provisionals and was functioning well without them. She was scheduled to return in 2 weeks to check soft-tissue healing and see if she was having any issues with eating without the use of the provisionals. At that appointment, she again indicated she was functioning well without the provisionals and was comfortable until her appointment to uncover the implants to initiate the restorative phase of treatment.

The patient was scheduled to see the OMFS at 4 months for implant uncovery, wherein he uncovered the implants under local anesthetic and placed healing abutments. The restoration was missing on implant No. 12. A panoramic radiograph was taken, and it was noted that the screw on No. 12 had fractured in the implant (Figure 2). A modification was made to the treatment plan for the maxillary arch. The crown would be removed on implant No. 15, and No. 12 would be buried with the full-arch restoration, including the current abutments on Nos. 14 and 15, to yield a zirconia bridge from Nos. 3 to 15. 

Figure 2. The panoramic radiograph following extraction of the natural teeth and implant placement after a 6-month healing period. The restorative phase of treat- ment was ready to be initiated.

After a soft-tissue healing period of 2 weeks, the patient returned to initiate the restorative phase. The crown was removed from implant No. 15, leaving its abutment on the implant. The healing abutments were removed, and closed-tray impression copings were inserted into each implant. Periapical radiographs were then taken to confirm full mating of the prosthetic part and the implant connectors. An impression was then taken in a full-arch tray of both arches utilizing NoCord light-body VPS (Centrix Dental) injected around the tissue aspect of each coping, and the tray was filled with NoCord MegaBody VPS (Centrix Dental). Upon setting, the trays were removed, impression copings were removed intraorally, and the healing abutments were reinserted. The provisional partial dentures would be utilized to capture the bite and occlusion. They were inserted, Access BLUE Bite VPS (Centrix Dental) was expressed over the occlusal surfaces, and the patient was guided into occlusion. Upon setting, the bite registration and provisional partials were removed as one unit to be sent to the lab.

The impressions, bite registration, and implant analogs with copings were sent to the lab (Glidewell) to start the prosthetic fabrication. A lab prescription was sent requesting custom abutments for implant Nos. 3, 5, 8, 9, 11, 21, 24, and 27. Additionally, provisional fixed restorations were requested to fit the custom abutments for Nos. 3 to 15 and 21 to 27. Soft-tissue models for both arches were fabricated at the lab utilizing the closed-tray impressions sent (Figure 3). These were then mounted on an articulator using the bite registration and provisional partial dentures (Figure 4). 

Figure 3. Soft-tissue models were created at the lab utilizing the open-tray impressions that had been sent.

Figure 4. The soft-tissue models were then mounted on an articulator using the bite registration and provisional partials.

Figure 5. Virtual models were imported into exocad (exocad) to start virtual design of the custom abutments and provisional bridges.

Figure 6. Virtual design of the abutments for cementable restorations for both arches.

Figure 7. Virtual design of provisional restorations to verify aesthetics intraorally.

Glidewell’s laboratory technicians scanned the soft-tissue models, created virtual models, and imported them into the lab’s system (Figure 5). Custom abutments were designed for the implants to be parallel with each other and the abutments on the old implants at Nos. 14 and 15 (Figure 6). Those were then individually milled from titanium on the Haas 5-Axis milling unit. They were then polished and finished. Next, virtual provisional bridges were designed to fit the virtual abutments previously designed in the lab’s system (Figure 7). Two sets of provisional bridges were milled in shade B2 using polymethyl methacrylate resin (BioTemps) on a Glidewell mill. One set would be used to capture a new bite registration intraorally and note any aesthetic changes desired, while the other set would be used as provisional restorations, allowing the patient to “test-drive” the aesthetics and occlusion. The custom abutments and resin placement jigs with the provisional bridges were returned to the office. 

Figure 8. Maxillary abutments on the soft-tissue model (left) and with an abutment placement jig seated over the abutments on the model (right).

Figure 9. Custom abutments were tried in, and seating was then verified radiographically.

The patient returned, and the healing abutments were removed intraorally from the anterior mandibular implants. The placement jig for the maxillary arch was placed on the abutments on the soft-tissue model, and the screws were removed from the abutments (Figure 8). The jig was transferred to the mouth and seated on the mandibular implants. The screws were inserted and finger-tightened. Periapical radiographs were taken to verify full seating of the custom abutments at the implant connectors. Upon verification, the screws were tightened to the implant manufacturer’s specifications with a torque wrench. This was then repeated on the mandibular arch (Figure 9). The provisional bridges were tried in over the custom abutments intraorally to verify full seating. The patient was shown a mirror, and she indicated she was happy with the shade. It was noted that the maxillary midline was tipped to the right, and that would be corrected in the final restorations. Photos were taken to communicate with the lab technicians (Figure 10). Teflon tape (PTFE) was placed into the screw access holes on the abutments to prevent cement contact with the screw heads. The provisionals were then cemented with NexTemp Temporary Cement (Premier Dental), and the patient was dismissed to “test-drive” the aesthetics for a few days. Four days later, the patient was called and asked if she was happy with the aesthetics and if she desired any changes. She expressed satisfaction with the shade and general aesthetics. We suggested decreasing the VDO so that less maxillary teeth showed when smiling, and she accepted that recommendation and the one to adjust the maxillary midline.  

Figure 10. Provisional restorations were tried in to allow the patient to aesthetically “test-drive” the restorations before any potential changes would be communicated to the lab.

Figure 11. Modifications were made in the virtual design to decrease the VDO, at the expense of the maxillary arch, and change the angle of the midline to a more vertical axis.

Figure 12. Virtual design of the maxillary and mandibular BruxZir monolithic bridges (Glidewell).

Upon receipt of the clinical photos, the second set of provisionals with midline angle correction was marked with a Sharpie marker, and we requested the lab tech also decrease the VDO at the expense of the maxillary arch and design the final prosthetics (Figures 11 and 12). The final bridges were milled from BruxZir Monolithic Zirconia (Glidewell) on a 5-Axis milling unit (Haas). Following milling, support legs were removed, and those areas were ground and polished, and then the bridges were fired to complete them (Figure 13). Stain was then applied to match the gradations on the VITA shade tab for B2 to achieve a natural appearance and eliminate a monochromatic aesthetic (Figure 14). The stained BruxZir bridges were fired, then glazed (Figure 15) and re-fired to finalize the monolithic bridges (Figure 16).

Figure 13. Maxillary final BruxZir full-arch and mandibular anterior BruxZir-cemented restorations following milling and processing.

Figure 14. The lab applied stain to the fired BruxZir restoration for characterization and verified it with the selected shade tab.

Figure 15. The lab applied glaze to the BruxZir restoration following baking the stain to finish the cementable implant bridge.

Figure 16. The final glazed and stained BruxZir restorations.

Figure 17. Placement of BruxZir Dual Cure Resin Cement (Glidewell) into the abutment crowns on the BruxZir bridge in preparation for cementation.

Figure 18. Final BruxZir maxillary full-arch and mandibular anterior bridge following luting with BruxZir Dual Cure Resin Cement and demonstrating final aesthetics.

The patient returned to the office, and the provisional bridges were removed intraorally. Any residual temporary cement was cleaned from the abutments intraorally. The BruxZir monolithic bridges were tried in to confirm passive seating over the implants on each arch. The occlusion was verified, and no adjustments were made. The patient indicated the bite felt even and comfortable. The interiors of the abutment crowns on each bridge were dried with a cotton pellet. BruxZir Dual Cure Resin Cement was placed into abutment crowns on each bridge at the interior marginal area, not filling the area so that, upon placement, the cement would not prevent full seating (Figure 17). The implant abutments were dried with gauze, and the bridge was seated fully on the maxillary arch. This was repeated with the mandibular bridge, and the patient was guided to bite into cotton rolls placed bilaterally in the posterior as well as one in the anterior. Following the setting of the resin cement, the cotton rolls were removed, and excess cement was marginally removed with a scaler. The patient was asked to occlude and indicated the bite felt even and comfortable. She was shown a mirror and indicated she was happy with the aesthetics, noting that it looked natural to her (Figure 18). The patient was scheduled for a post-insertion appointment at one week to check and confirm the occlusion after she had time to function with it.

CONCLUSION

Complex treatments, especially when a full arch is being treated, can provide challenges to achieve the patient’s desired aesthetic goals. The team approach aids in achieving the planned goals while decreasing stress on the practitioner, resulting in a satisfied patient at the completion of treatment. As outlined in the case presented, planning needs to follow each patient’s expressed treatment requests with regard to aesthetics and function. Additionally, in complex cases, when placing implants on an arch where previously placed and restored implants are present on natural teeth that were not being treated, changes may result during the treatment process that require modifications in the treatment plan. Coordination with the lab team aids in incorporating necessary changes as they may arise. 

Cementation of zirconia restorations has posed a challenge in the past, with the potential of debonding from the zirconia being a common occurrence. BruxZir Dual Cure Resin Cement has high bond strengths to dentin, etched enamel, metal (metal-based restorations or implant abutments), ceramics, and zirconia, allowing its use in any clinical application that requires cementation.

ACKNOWLEDGMENTS

The author would like to thank Dr. Anis Tebyanian, for the oral surgery aspects of the case presented, and the following Glidewell technical experts who assisted through the planning and execution of the discussed case: Catalina Bollman, senior manager, dental production; Luis Rodriguez, CAD/CAM scanner; Jorge Espinoza, CAD/CAM designer; Isaiah Porter, quality control, final; Steve Tran, cement technician III; Nhi Tran, dental technician; Danny Nguyen, CAD/CAM design technician; Mike Lee, manager, dental production; Haiping Li, glaze team leader; Celine Jun, stainer; and Erik Baltazar, manager, dental production. Thank you!

ABOUT THE AUTHOR

Dr. Kurtzman is in private general practice in Silver Spring, Md. A former assistant clinical professor at the University of Maryland, he has earned Fellowships in the AGD, the American Academy of Implant Prosthodontics, the American College of Dentists, the International Congress of Oral Implantologists (ICOI), the Pierre Fauchard Academy, and the Association of Dental Implantology; Masterships in the AGD and ICOI; and Diplomate status in the ICOI and the American Dental Implant Association. He has lectured internationally, and his articles have been published worldwide. He has been listed as one of Dentistry Today’s Leaders in Continuing Education since 2006. He can be reached via email at dr_kurtzman@maryland-implants.com.

Disclosure: Dr. Kurtzman reports no disclosures. 

Clinical procedures concerning the need for posts and the protocol for core buildups in endodontically treated teeth have evolved significantly over the last few decades with the advent of dentin bonding protocols. Likewise, the dental literature has evolved yet is fraught with contradictions. However, the consensus in the literature today is that posts weaken teeth, and when adequate tooth volume is present, a post is contraindicated, and only a core buildup should be done. 

There is a misconception often quoted in the literature that the reason a post is needed is to retain the core buildup. Perhaps this was true before adequate dentin bonding protocols existed, but this is simply no longer true. Posts cannot retain a buildup because the post itself is retained by the cement and buildup. Posts have no inherent retention. The only reason to place a post is to avoid horizontal fracture of the core buildup. In addition, many authors subscribe to the necessity of the ferrule effect, while others debunk the idea. Many clinical studies on the ferrule effect are simply studying residual tooth structure volume rather than any effect ferrules may have. Clinical decisions on how to best restore endodontically treated teeth must be made with a jaundiced eye toward the literature since there are so many contradictions in the “evidenced-based” literature.

Much of the conflict in the endodontic literature on post placement stems from the clinical protocols used in the studies. Any study done using paper points to dry a canal where dentin bonding is used is flawed because paper points simply will not sufficiently dry a canal for dentin bonding to work. Studies done with acid-based cements that do not bond to the unique post space dentin and the post are also flawed. Likewise, the use of dual-cured resins to place posts results in a flawed study since complete conversion requires light activation, and light will not penetrate to the depth of a post space. 

Therefore, a clinician is left to decide on how to restore an endodontically treated tooth based on observable “facts” within their own practices. Those observations over decades with teeth they have restored and followed will lead the clinician to prudent management. I have been fortunate to have observed these “facts” for more than 5 decades. My first lecture was in 1972 to our local dental society on how to fabricate and place a gold post. Since that time, I have restored thousands of endodontically treated teeth out of the more than 65,000 units I have placed and have been fortunate to practice in the same community for more than 50 years. I have followed the outcome of what I did for my patients on the majority of those 65,000 units. As materials and my experience evolved, so did my clinical protocols on how best to restore endodontically treated teeth. 

Here are the thoughts I have on restoring endodontically treated teeth today in the 21st century based on my clinical experience for more than 5 decades and a belief in shards of uncompromised dental literature: 

1. Properly restored teeth are better than implants. Implants are considered the route of last resort in our office. Well-done endodontic treatment, coupled with appropriate restorative procedures, can preserve teeth for decades. 

2. Posts should not be placed when there is no need since the placement of a post weakens teeth and is fraught with complications both from the endo-
dontic fill and biomechanical perspectives.

3. Active screw posts should never be used because they split teeth. 

4. Acid-soluble cements should never be used to place posts. The function of the cement is to retain the post. Acid-base cements are too weak to do that.

5. Glass ionomer cemented posts do not resist the formation of decay along the post space. 

6. The need for a post is not to retain the core but rather to prevent horizontal fracture of the core buildup. There is no other need for a post.

7. Posts are not indicated for teeth that are not planned for full-coverage restorations.

8. Posterior endodontically treated teeth require cusp-coverage restorations. Simple direct composites as definitive restorations are inadequate for the long-term success of endodontically treated teeth. 

9. Metal posts resist fracture of the core better than plastic or ceramic ones, which are prone to fracture.

10. Post spaces should never be initially prepared with end-cutting drills. Root perforation is common when this is done. Initial prep to depth (anything less than 10.0 mm is almost worthless) should be done with Peeso reamers or Gates Glidden drills, followed by sizing the post space with the end-cutting drill.

11. Post spaces can only be properly rinsed and dried with a Stropko Irrigator (Stropko). Paper point drying a canal to evaporate alcohol or acetone in primers simply will not take the substrate to the hydrophobic level necessary for successful bonding.

12. Teeth with core buildups that have adequate dimensions to resist fracture do not need posts. Molar teeth with posts result in many catastrophic failures. 

13. Core buildups should always be separate from the crown. Casting, pressing, or milling the core as part of the crown is a significant compromise.

14. The primary cause of failure on teeth restored with posts is root fracture, which is secondary to the cement’s failure to retain the post. Once the post is loose, any occlusal force will likely stress the fragile root enough to fracture it.

15. The secondary cause of failure on teeth restored with posts is coronal microleakage down the post space, resulting in failure of the endodontic fill.

16. Endodontically treated teeth become brittle over time and, additionally, are usually biomechanically compromised. Appropriate distribution of occlusal forces on endodontically treated and restored teeth is critical for long-term success.

17. Posts should be embedded in the core buildup as much as possible since the opacity of the buildup will block the appearance of the metal post, and if it is centered in the buildup, it will increase the fracture resistance of the buildup.

18. Titanium posts do not rust like stainless steel. Rust compromises cosmetics. Flexure of the core buildup causes fracture of the buildup and, frequently, the roots. Plastic posts flex and often break because they do not resist fracture of the core buildup. Ceramic posts do not flex but fracture easily.  

19. Titanium ParaPosts XP (Coltene) smaller than 4.5 are flexible and should be used with caution. Titanium alloy is more flexible than stainless steel, but that flexibility is clinically insignificant. 

20. Only chemically activated composite cement should be used to cement posts. Dual-cure cement requires light to fully cure, and light will not penetrate to the base of the post space where a complete cure is mandatory.

21. Molars almost never need posts since the volume of core material will not need to be reinforced to prevent fracture.

22. Bicuspids rarely need posts unless they are fractured off at the tissue level.

23. Most posts “succeed” because there was never a need to place one initially. This is one of the confusing aspects of retrospective studies on posts. 

24. There are cases where heroics can keep a tooth for quite some time, but when the volume of tooth structure is severely compromised, the prognosis is poor, and the outcome eventually will be failure.

25. It is prudent to attempt heroics when the age of the patient is factored into the treatment plan. Elderly patients may well benefit from a decade or so of service out of a heroic attempt to keep a tooth. Likewise, younger patients may benefit from keeping a tooth for a decade or so as the knowledge and prognosis of implant management grows at an exponential rate. Who knows, but what stem cell may grow a new tooth in the next decade or so? 

26. Placing a post or core buildup requires a precise protocol to ensure decades of success. Protocols that we use for core buildups and post placement are free to download at our website,
struppbrummseminars.com. Click on “Protocol Downloads” to access them. These protocols are bulletproof, if followed precisely. In addition, our products list is also free to download. It contains all the products we use and a contact source to get them. 

Two cases are presented here with captions to explain what was done. In addition, other photos are included to expand on certain aspects that require clarification. If you have any questions about this article, we will be happy to answer them on our Facebook page, Strupp/Brumm Dental Protocols, where more than 16,000 of the best dentists in the world gather to learn. 

CASE REPORTS

Case 1: Teeth Nos. 6 to 11 necessitated replacement. These restorations were made with porcelain butt joints in the cosmetic zone and placed with zinc phosphate cement. Posts were placed with Fuji Glass Ionomer Cement (GC) in Nos. 7, 8, and 10 (Figure 1).

Figure 1. Recurrent decay around and under 30-year-old porcelain-fused-to-gold restorations.

Case 2: Black discoloration along the labial porcelain butt joints was clinical evidence of decay. A 0.2 to 1.0 mm of recession over 30 years, coupled with the black discoloration along the margins, created a “cosmetic need” for the patient. The degree of pathology under the restorations was not clinically evident. Most restorations cemented with acid-soluble cement should be replaced after 2 to 3 decades, even if they “look” good (Figure 2).

Figure 2. Black discoloration along the labial porcelain butt joints.

After removing the old restorations, a significant amount of tooth structure was decayed because of the leaking restorations and dissolution of the acid-soluble cement. This was made worse by the patient’s habit of drinking acidic beverages. There was no bleeding tissue because a soft-tissue scrub with Pure 4% CHG (Best Buy Discount Dental Supply) was done 2 days before the preparations (Figure 3).

Figure 3. After removing the old restorations.

Case 3: Extensive loss of tooth volume occurred as the diseased tooth structure was removed. The glass ionomer cemented posts were removed using a sonic scaler. This exposed extensive decay along the post space walls, especially in the post space of No. 8. Because the projected volume of core buildup in No. 8 would satisfactorily resist horizontal fracture, a post was not indicated. Posts were indicated to resist horizontal fracture of the core buildups in Nos. 7 and 10, however, because the projected thin dimension of the core buildups were at risk for horizontal fracture without them (Figure 4).

Figure 4. Extensive loss of tooth volume.

Case 4: Our post placement protocol is the most critical protocol we use in advanced restorative cases, and the substrate to which we will bond must not be compromised. OpalDam Green (Ultradent Products) was used to cover the substrates and post spaces in Nos. 7 and 10 to prevent the products used in the core buildup protocol for Nos. 6, 8, 9, and 10 from touching the substrates and post spaces (Figure 5). 

Figure 5. OpalDam Green (Ultradent Products) was used to cover the substrates and post spaces.

Case 5: Core buildups were done for Nos. 6, 8, 9, and 11. Excessive buildup material was placed to allow preparation of an ideal shape and form and to cover as many open tubules as possible in the vital teeth. Properly done core buildups on vital teeth are like immediate dentin sealing on steroids (Figure 6).

Figure 6. Core buildups were done for Nos. 6, 8, 9, and 11.

Case 6: Using the Strupp/Brumm protocol, 4.5 Titanium ParaPost XP (Coltene) posts were placed with the chemical cure cement PANAVIA 21 (Kuraray). The core buildups were placed simultaneously with post cementation so that both composites would set together. There is a dot after the 4 and before the T on the post. This indicates a size 4.5 and that the post is titanium alloy (Figure 7).

Figure 7. Titanium ParaPost XP (Coltene) posts.

Case 7: Definitive preparations were done. We avoid touching the tissue as much as possible while creating an ideal shape and form to the abutments, which will accept the final lithium disilicate restorations. A single Sil-Trax Epi #00 retraction cord (Pascal) was soaked in Retrax AC (Pascal), blotted, placed, and immediately rinsed after placement on each tooth. Highly acidic hemostatic agents (which all hemostatic agents are) must immediately be rinsed to avoid severe damage to the abutments and necrosis of the tissue. Postoperative sensitivity usually results if these agents are not thoroughly rinsed immediately after use (Figure 8).

Figure 8. Definitive preparations were done.

Case 8: The ideal shape to make a perfect chamfer margin is the Diamond Bur #6877K/014 (Brasseler), which has a 55° elliptical radius. The same shape in the Polaris Diamond is #G-62 (Figure 9).

Figure 9. Brasseler and Polaris Diamond Burs.

Case 9: A definitive impression using Imprint 4 VPS (3M) was made that recorded unprepared tooth structure apical to the margin along with the entirety of the preps. We believe all margins recorded in an impression must include sound tooth structure apical to them to ensure a perfect fit of the final restoration (Figure 10).

Figure 10. A definitive impression using Imprint 4 VPS (3M).

Case 10: The cast from the first pour of the impression is used for dies. A second pour cast is made but not sawed. The second pour cast is used for checking proximal contacts on the final restorations after the soft-tissue zones are trimmed away from the margins to ensure a definitive seat of the final restorations (Figure 11).

Figure 11. The cast from the first pour of the impression was used for dies.

Case 11: Provisional restorations that fit perfectly and are cemented with Durelon (3M) are critical for tissue health on the day of final cementation. Patients are seen one week post-op to ensure all provisional cement is removed and the patient is doing appropriate home care and for a scrub with Pure 4% CHG (Best Buy Discount Dental Supply). Controlling the microbiome during the provisional phase is critical for long-term success. Cementing into a pool of blood produces certain failure, and is a disservice to the patient (Figure 12).

Figure 12. Provisional restorations that fit perfectly and were cemented with Durelon (3M).

Case 12: Durelon sticks to the teeth when the provisionals are removed. Its antimicrobial character keeps vital pulps vital and calm and minimizes the issue of cement sepsis (microbial growth under a restoration). Durelon is easily removed with a SONICflex (KaVo), which leaves black marks on the buildups. Painless anesthesia is always used for definitive cementation because we never want to hurt a patient during the placement process. Without anesthesia, the patient will never refer their friends because we hurt them (Figure 13).

Figure 13. Durelon sticks to teeth when provisionals are removed.

Case 13: Air abrasion with CoJet Sand (3M) removes all of the black marks and residual Durelon. Air abrasion can open a capillary, but that is usually very easy to control by scrubbing the open capillary with Retrax AC, which must be thoroughly rinsed away to avoid compromising the resin cement and substrate to which we will bond (Figure 14).

Figure 14. Air abrasion with CoJet Sand (3M).

Case 14: The cosmetic outcome is approved by the patient before definitive placement. Tissue health is mandatory for placement. A Pure 4% CHG scrub 2 days before placement minimizes bleeding, which is caused by a dysbiotic microbiome that invariably forms around margins on provisional restorations near the tissue. The second pour solid cast with the tissue trimmed away is used to confirm perfect interproximal contacts in the laboratory. Adjusting contacts clinically is a time suck and invariably results in loss of patient confidence (Figure 15).

Figure 15. The cosmetic outcome was approved by the patient.

Case 15: All of our patients are taught preventive dentistry techniques, and any bleeding tissue is scrubbed with Pure 4% CHG on a weekly basis until there is no bleeding due to aggressive brushing. This patient received preventive dentistry instructions, 3 scrubs with Pure 4% CHG, and a prophy. The microbiome present at the end of this protocol was symbiotic, and there was no bleeding tissue. The success of any clinical protocol depends on soft-tissue health before, during, and after the using the protocol. Posts or core buildups cannot successfully be done in a sea of blood, nor can cementation be successful in such conditions (Figure 16).

Figure 16. Results using Pure 4% CHG (Best Buy Discount Dental Supply).

Case 16: The photos before core buildups/post placement and after crown placement were remarkable and were given to the patient. The anterior envelope of function was designed in the laboratory with the weak teeth in mind, and occlusal loading was placed where it could best be sustained by the available biology. Communication with the laboratory and precise placement protocols are critical in cases with weakened biology. The bonding protocols used for post placement and core buildups will make or break a case of this complexity, but they are meaningless unless the occlusal forces are properly distributed (Figure 17).

Figure 17. Patient before and after photos.

Case 17: When does the implant become the treatment of choice? Should heroic dentistry be done? Every dentist must make this decision and live with the consequences. If a patient says he or she wants to keep the tooth, when do we say no? This patient was in his 80s, and the fee was no object. He just wanted to keep the tooth. I explained the poor prognosis and proceeded to accommodate his wishes (Figure 18).

Figure 18. Preoperative image of an 88-year-old patient.

This case will combine many of the issues and treatments discussed here so far. An 88-year-old patient had been keeping a loose post/core/crown in place with denture adhesive for over a year. His dentist was OK with that. He was also OK with the obvious failing dentistry. Go figure? Before I understood proper bonding protocols for core buildups on these vital teeth, I was afraid the core buildup would come out when I removed the provisional. This is an unwarranted fear today because our buildup protocol is bulletproof. 

Only a shell of a tooth was left, and decay extended close to the crest of the bone. Removing bone to accommodate a ferrule or to gain crown length to avoid the issue of violation of the biologic width would compromise the bone needed for an implant when one would most certainly need to be done at some point in time for this case. A closed-flap biologic shaping protocol was used instead to allow fabrication of a final restoration with an equigingival margin (Figures 19 and 20).

Figure 19. Extract, implant, or restore?

Figure 20. Hopeless?

A post was placed to resist fracture of the core buildup in No. 10, and closed-flap biologic shaping was accomplished with the plan to marginate at the crest of the tissue on core paste after healing. The core buildup on No. 10 was in violation of the biologic width, but it was reshaped along with tooth structure apical to it, then both the prepared root surface and core buildup were highly polished. Core buildups were d one on the vital teeth Nos. 7 to 9. The provisional was made on No. 10 with margins well coronal to the tissue level to allow proper healing. See Figure 21 for what it looked like 1 month later. 

Figure 21. CFBF and 1 month later.

He returned 7 months later for re-evaluation. The objective of closed flap biologic shaping is to create an interface between the soft tissue and the core buildup, which was placed in violation of the biologic width in a perfectly dry environment, that can be maintained with good home care and Pure 4% CHG scrubs every 3 months. There is no “attachment” of the soft tissue to the core buildup; rather, there is a hemidesmosomal approximation of the soft tissue to the core buildup, much like what exists with implants. The post will resist fracture of the core buildup and is hidden by it, so metal is not a cosmetic issue when the post is properly contained within the core buildup. Ceramic or resin posts are woefully inferior in resisting fracture of the core buildup on thin teeth. The patient was away for 7 months before we had a chance to finalize the case. Well-made provisionals will enhance healing (Figures 22 to 24).

Figure 22. CFBF and 7 months later.

Figure 23. Preparations.

Figure 24. Seven months post closed-flap biologic shaping.

Here is how the case resolved at 2.5 years after placement. The final monolithic Lisi Press (GC) case with equigingival margins placed on the core buildup on No. 10 resulted in perfect tissue health. Clearly, this case is destined to fail if the patient bites into little more than a potato chip, but he has been very careful not to abuse the severely compromised biomechanical situation. Without proper protocols for placement of the post and core buildup and appropriate distribution of occlusal forces, this case would have failed within weeks (Figure 25).

Figure 25. Photo 2.5 years after placement.

We should mention here that all of our cases, which are either HP 77 gold (Argen) or Lisi Press, are bonded in with PANAVIA F 2.0 (Kuraray). It is the only cement we have used this century to place our restorations (more than 25,000 units). 

CONCLUSION

Some final words about our post and core preparation protocol. Correct positioning of a post can be accomplished using a prep shim with a hole drilled just lingual to the incisal edge for the post to exit coronally so it is positioned exactly where is should be to both support the buildup in resisting fracture and be hidden by the core buildup. This keeps the post from being visible. There is simply no need for a “cosmetically” colored post that is too weak to resist fracture (Figure 26). The sequence is critical. The post is placed using our PANAVIA 21 cement protocol, Core Paste XP Enamel (DenMat) is used to displace as much of the cement as possible, the prep shim is seated to guide the post into the correct position before the snap set of Panavia 21 occurs, and the rest of the core buildup is “injection molded” through the hole in the prep shim (Figure 27). The posts then must be properly covered. The prep shim properly positions the posts to aid in resisting horizontal fracture of the core buildup (Figure 28). As a result of following this sequence, no metal shows. The opacity of Core Paste XP Enamel blocks metal easily. Margination subgingivally is necessitated by the discolored roots secondary to long-standing root canals (Figure 29).

Figure 26. Prep shim with hole drilled just lingual to the incisal edge.

Figure 27. The sequence is important.

Figure 28. Posts properly covered.

Figure 29. No metal shows.

We hope we have brought you along on this 50-plus-year journey helping patients with more than 65,000 units and given you all new ways to look at your patients and give them the best possible care.

ABOUT THE AUTHORS

Dr. Strupp was the inaugural speaker at the American Academy of Cosmetic Dentistry (AACD) founding meeting in 1984. He is an Accredited Fellow in the AACD. Fellowship, a select group of fewer than 100 people worldwide, is the highest level of achievement recognized by the AACD. The status of Accredited Fellow of the AACD is granted only after completion of all requirements. He is or has been a member of virtually every meaningful academy in dentistry. Dentistry Today has selected Dr. Strupp as a Leader in Continuing Education in dentistry every year the leaders have been recognized. He has lectured to more than 45,000 dentists and is considered to be at the top of the most elite group of teachers in dentistry. Elite clinical results are routine for the many complex cosmetic and restorative cases he has completed since entering private practice in 1969. He can be reached at bill@strupp.com. 

Dr. Brumm received his DMD degree from the University of Louisville in 2006. He is an Accredited Fellow Member of the American Academy of Cosmetic Dentistry. He is also former president of the Florida Academy of Cosmetic Dentistry. Dr. Brumm is a certified dental technician. The CDT designation is a great achievement and demonstrates a significant mastery of the knowledge and applied skills needed in dental technology. Dr. Brumm has also lectured nationally and internationally to dentistry professionals on the subject of simplifying complex cosmetic and restorative dentistry. He can be reached at mike@strupp.com.

Disclosure: Drs. Strupp and Brumm manufacture and sell Pure 4% CHG. 

The art and technique of direct composite restoration of anterior teeth continues to gain popularity with a demand for minimally invasive procedures. Social media is a significant source of information for patients to view the possibilities for anterior restorative options through photographs and videos posted by dentists. For many dentists, the challenge of understanding which composite(s) to use, how to layer it, how to appropriately prepare the tooth, and how to finish and polish the final restoration can be frustrating. Again, social media can be a powerful source of information about techniques and materials that are commonly being used by well-known dentists around the world.

The most common direct composite restorations on anterior teeth are Class IV fracture repairs and adding incisal length. In either case, there is a hard incisal edge that has to be masked out, and one of the most common mistakes is having a show-through of the incisal edge against the more translucent composite. In addition, if a more opaque shade is used, it will not blend against the opalescence of the natural tooth. The challenge for most dentists is to know how to layer the different types of composites if using a polychromatic approach. Similarly, with the advent of new single-shade composite systems that simplify tooth color matching without complicated layering, there are still principles of layering that need to be followed for optimum results. 

There are 2 basic principles to consider in order to create a direct composite restoration that blends and masks properly. First, the tooth preparation should include a proper inciso-facial bevel to allow for feathering of the composite onto the facial surface. Second is the proper application of the single-shade composite system in conjunction with the supplementary product, which typically has more opacity. One way to consider these 2 materials is to think of the omnichromatic composite functioning as the enamel with a certain amount of translucency and the supplementary composite functioning as the dentin with more opacity. The examples shown below will illustrate common errors when using these 2 materials on an extracted lower anterior tooth and then give a clinical example of how to properly use it.

CASE REPORT

There are differing opinions on creating an ideal inciso-facial bevel for direct anterior composite restorations. Nevertheless, the principle of creating a bevel is true for both increased retention as well as aesthetic blending of the composite. The exact size and shape of the bevel is not the focus and will not be addressed here. In the following examples, a conservative 45° infinity bevel was used as well as air abrasion with 27-µm aluminum oxide (Figures 1 and 2). As a reference, the single-shade composite system used in these examples is OMNICHROMA (Tokuyama Dental America). However, similar single-shade composite systems can follow the same principles outlined herein. 

Figure 1. Extracted lower incisor showing a common type of Class IV fracture.

Figure 2. Facial and lateral views showing a conservative 45° infinity bevel and micro-air abrasion with 27-μm aluminum oxide.

For the first example, only OMNICHROMA was used. What you will notice is that there is too much translucency in the final restoration, and you can see the hard line of the fracture through the composite (Figure 3). This occurs because a single-shade composite system does not have any color and cannot mask a hard line by itself. A single-shade composite system obtains its color from the underlying tooth structure, so when it is used to restore surfaces beyond the natural tooth, it will result in show-through and appear gray or translucent. To correct this problem, a supplementary composite must be used in conjunction, which will be explained and shown below. 

Figure 3. Only OMNICHROMA (Tokuyama Dental America) was used to restore the entire restoration, which ended up having show-through, and the hard incisal edge was visible, creating an unsatisfactory result.

Figure 4. Too much OMNICHROMA BLOCKER (Tokuyama Dental America) was used to create the lingual shelf, which went over and onto the facial surface.

Figure 5. With too much BLOCKER, the final restoration ends up looking opaque even after the final layer of OMNICHROMA is placed.

In the second example, the supplementary composite, OMNICHROMA BLOCKER, was used to create a palatal shelf. OMNICHROMA was then placed and sculpted to the final contour and polished. As you can see, the BLOCKER layer was placed too thick (Figure 4). When this happens, the final restoration will have too much opacity, and the hard incisal edge will still be visible. However, instead of being too translucent like in the first example, it was too opaque and reflective (Figure 5). The error here was that the supplemental composite was feathered over and onto the facial surface rather than keeping it back by the linguo-incisal line angle. Care must be taken to place and shape this lingual shelf appropriately. 

In the third example, the BLOCKER and OMNICHROMA were placed correctly. This was done with the aid of a silicon putty matrix made from a diagnostic wax-up, but it could similarly be done using a mylar strip to create a basic palatal shelf. Both are acceptable methods. Freehand layering of composite without the aid of a lingual guide is more difficult in controlling the thickness and shape. To correctly layer the BLOCKER as a palatal shelf, it is important not to let it go onto the facial surface but rather keep it back against the palatal aspect of the incisal edge (Figure 6). There is no perfect or magical thickness measurement, but it should be kept to 0.5 mm or less. If it is too thin, you will know immediately because once the palatal layer is cured, you will be able to see through it. If this is the case, just add a little more BLOCKER. Once we were satisfied with the palatal shelf layer, OMNICHROMA was placed to the final contour (Figure 7). Some composites have a creamier consistency; therefore, some dentists prefer to place it in several layers rather than one thick layer for easier sculpting without slumping.

Figure 6. Proper layering of the BLOCKER lingual shelf with a thickness no greater than 0.5 mm and not overlapping onto the facial surface.

Figure 7. Final layer of OMNICHROMA over the BLOCKER lingual shelf.

Figure 8. Preoperative full smile view of teeth Nos. 8 and 9 with old composites that were stained and failing.

Figure 9. Pre-op retracted view of teeth Nos. 8 and 9 with old composites that were stained and failing.

Figure 10. Close-up view of a tooth preparation using a 45° bevel and micro-air abrasion.

Figure 11. A thin lingual shelf fabricated with OMNICHROMA using a silicon putty index made from a diagnostic wax-up. This layer must be very thin and must not overlap onto the facial surface.

Figure 12. BLOCKER layer applied to mimic the dentin layer while leaving suf- ficient space for the final OMNICHROMA layer.

Figure 13. Final OMNICHROMA layer placed using Mylar strips to form interproximal contacts and embrasures.

Figure 14. Immediate postoperative retracted view of the final restorations.

Figure 15. Immediate post-op full smile view of the final restorations.

The final example shows a clinical case where a modified layering technique was used to achieve maximum aesthetics with this single-shade composite system. Teeth Nos. 8 and 9 were previously restored in this patient’s youth after a skateboard accident. These restorations had functioned well for a number of years, but the patient had become more self-conscious and concerned with the show-through and appearance as the margins began to stain (Figures 8 and 9). The old composites were removed without anesthetic using a coarse diamond bur (Komet) and Sof-Lex disc (3M). A fine-grit diamond bur (Komet) was then used to create a 45° infinity bevel, and this was followed by air abrasion (MicroEtcher II [Zest Dental Solutions]) well beyond where the estimated composite finish line would be (Figure 10). Likewise, the acid etch and bonding resin were placed well beyond the estimated finish line, ensuring that the composite margin would be seamless after finishing and polishing. Using the silicone putty index (Burkhart Dental), the palatal shelf was created with a very thin layer of OMNICHROMA (Figure 11). The BLOCKER was then sculpted to replicate the dentin layer (Figure 12). This was done by feathering the BLOCKER onto the facial bevel just enough to block out the hard fracture line while leaving enough space to place a final layer of OMNICHROMA over the top. A Mylar strip was used to pull the final layer of OMNICHROMA interproximally and shape the facial embrasures (Figure 13). Shaping and polishing were completed with a series of Sof-Lex discs (3M), burs (Komet), and composite polishers (Kerr). Although the surrounding dentition was dehydrated, the immediate postoperative photos show how well a single-shade composite system works when layered properly (Figures 14 and 15). In some cases where the teeth are highly characterized with translucency or white spots of hypocalcifications, colored resins can be used to paint and create the desired subtle effects before placing the final thin layer of the single-shade composite. In this particular case, it wasn’t needed, and it was the desire of the author to show how a single-shade composite system can look without overcomplicating the process. 

CONCLUSION

Hopefully, this article is successful in not only showing how to correctly handle and layer a single-shade composite system to achieve excellent results but also to help one understand what not to do so you can avoid common mistakes that result in patients being unsatisfied and the dentist being frustrated. With a better understanding of how a single-shade composite system works and why a supplementary material is needed in situations like adding length, you can be more confident in getting it right the first time. Or if an error is made, you will know what went wrong and how to fix it and be less likely to repeat the mistake in the future. Like anything in dentistry, or in life for that matter, practice makes perfect. Anyone who wants to master a technique or become familiar with a new composite or dental material should take the necessary time to practice and perfect it. One of the advantages of a single-shade composite system is that it is very forgiving, and there is more room for error to still end up with acceptable results because of its omnichromatic color-matching ability. Find your balance and get the ideal shade match you are looking for with this single-shade composite system.

ABOUT THE AUTHOR

Dr. Brown attended the University of Washington school of dentistry and has been in private practice in Bellevue, Wash, since graduating in 2006. He quickly fell in love with the art of direct composite bonding and the versatility of composite resins and developed his composite handling skills through the accreditation process of the American Academy of Cosmetic Dentistry. He also enjoys photography and uses it in his everyday practice to improve his clinical dentistry, lab communication, patient education, and training of other dentists. He has a passion for minimally invasive cosmetic techniques and has published numerous articles and lectures on direct and indirect anterior smile enhancement. Dr. Brown enjoys learning and sharing what he knows with others. You can see many of his techniques that he shares on Instagram @dr.kevinbrown. He can be reached by email at kbrown@kmbdds.com or the Instagram handle @dr.kevin_brown.  

Disclosure: Dr. Brown received an honorarium from Tokuyama Dental America for writing this article.   

UPCOMING WEBINAR

Dr. Brown will present a FREE Live Webinar on October 20, 2023, expanding on this article’s topic.

Click here to visit dentistrytoday.com/webinar and sign up today!

Meet Carson. He lost tooth No. 9 at the tender age of 14 after a battle to resolve its developmental impaction (Figure 1) and reoccurring infections (Figures 2 to 5). He had multiple failed Maryland bridges (Figure 6), and his current dentist had told him there was nothing further they could do to help him. Carson’s orthodontist, who had been overseeing the case for 6 years, referred the family to me. When Mom called to schedule the initial visit, she said, “Our dentist has fired us, and we have no one to turn to.”  

Figure 1. Panoramic x-ray showing the developmental impac- tion of tooth No. 9.

Figure 2.

Figures 2 and 3. Exposing and bonding and bringing tooth No. 9 into position were somewhat successful, but reoccurring infections at No. 9 could not be resolved.

Figure 4.

Figures 4 and 5. Even after extraction, it still took time and additional procedures by the oral surgeon to clear the infection. The loss of the tooth was catastrophic but necessary.

INITIAL PERSONAL THOUGHTS

When I met Carson, he was 16 years old and wearing an Invisalign tray (Align Technology) with missing tooth No. 9 painted in White Out. It was really heartbreaking and something I had never encountered. His self-esteem was circling the drain, and his parents were terrified these circumstances would permanently scar him. He was sullen, moody, and would barely look at me. He wore a hoodie with the hood pulled up at all of his visits with me. He couldn’t bring himself to smile for clinical photos—he honestly did not know how (Figures 7 and 8). The vivacious, confident, smart young man that his parents had raised was vanishing before their eyes. His orthodontist saw what was happening and stepped in to help by sending Carson to me. 

Figure 6. One of the Maryland bridges before it failed. The family and patient had been a little underwhelmed by the aesthetics of this Maryland bridge.

Figure 7.

Figures 7 and 8. Carson couldn’t even smile for clinical photos—he honestly did not know how. This was the best smile we could coax out of him.

DEVELOPING A PLAN

An ideal scenario when a patient is missing a tooth is the placement of a dental implant. Not only was Carson too young for this option but the space available for an implant was also too narrow both bucco-lingually, due to the destruction of the bone by the recurrent infections, and mesiodistally, as confirmed by the oral surgeon who extracted the tooth after multiple attempts to bring it into position by the orthodontist (Figures 9 and 10). The lack of adequate space for an implant was also confirmed via a CBCT scan. The orthodontist did not feel that putting any more orthodontic forces on the already compromised tooth No. 10 was a good option, especially considering the abbreviated root structure and its proximity to the site of recurrent infections. This was confirmed in the radiograph (Figure 11). Carson had already been through 6 years of orthodontics, both early/interventional and conventional, with a few pauses periodically while the endodontist and oral surgeon treated the recurrent infections at No. 9. 

Figure 9.

Figures 9 and 10. Final orthodontic space for No. 9 and the continuing battle to resolve the infection.

After spending considerable time studying Carson’s case with an experienced and highly skilled ceramist, we feared that a new Maryland bridge was not a viable option. The factors affecting his candidacy for a Maryland bridge included the large width of the space available; the tilt and shape of the surrounding teeth; and the thick gingival tissue on the facial of the site where tooth No. 9 was missing, which would have required a very long wing (Figure 12). These factors may have contributed to the failure of 2 previous Maryland bridges and Carson being “fired” by the previous dentist. (The family was never pleased with the aesthetics of the old Maryland bridge, either [Figure 6].)

While not the most ideal, we did still have options for Carson. The parents, the orthodontist, and I began discussing crown and bridge. The downside of this option was the removal of mostly healthy tooth structure on the abutment teeth—particularly in such a young patient—for no other reason than to replace missing tooth No. 9. However, the advantage was that this option had the potential to be the most aesthetic of all available options, and it would certainly be much more stable with a better prognosis than a Maryland bridge. Carson was also at high caries risk; note the incipient interproximal lesions on the anterior teeth (Figure 11). Further, he had 2 mm of overjet, meaning that the lingual surfaces of his maxillary anterior teeth would not even need to be prepared, and the bridge would be exempt from normal occlusal forces. 

Figure 11. Inadequate space for an implant for No. 9. Note the abbreviated root structure and tipping of tooth No. 10.

Figure 12. Note the thick facial tissue where No. 9 was missing, which made this site less favorable for a Maryland bridge.

Finally, it is very helpful to have an option that has fallbacks or safety nets, ie, if plan A fails, we still have a plan B. Most of the time, extracting teeth and placing implants is the final plan—if an implant fails, there aren’t usually many alternatives to that treatment option other than hoping the implant failure did not destroy bone in such a manner that would prevent an additional redo attempt at implant therapy. So while implant therapy is often the ideal solution for missing teeth, looking at cases like these, we look for a restorative plan that may work for some period of time before resorting to implants. Attempting to use the existing natural teeth first, even if they aren’t perfect, rather than just extracting them and going straight to an implant plan is often the best solution. It is often surprising how many years an alternative restorative plan can “buy” the patient prior to extractions and implant placement. 

In Carson’s situation, tooth No. 10 was already compromised, and the case was made that if we continued orthodontic treatment, we risked losing that tooth as well and continuing to damage Carson’s self-esteem in the process. I told the family if we could stop ortho after 6 years of orthodontics and get an immediately excellent aesthetic result for Carson, what’s the worst that could happen—the failure of a bridge abutment? It seems (optimistically) unlikely, considering the entire maxillary anterior was not in occlusion, but if we did lose one of the bridge abutments (tooth No. 8 or 10) all of a sudden, we would have room for an implant that could serve as a cantilever bridge option. This would be our “plan B” if plan A failed. So we started talking about a conventional bridge from Nos. 8 to 10 with a porcelain veneer for No. 7 to make it symmetrical, treating as few teeth as possible. I witnessed the family’s growing excitement about trying something different for Carson. 

PRESENTING THE PLAN TO PATIENT AND FAMILY

In the interest of thoroughness, which I believe all patients deserve, here are the options I gave the family. 

Option 1: Placement of a crown on compromised tooth No. 10 with a pontic cantilevered off it to replace No. 9. The upside of this option was that it would be much more stable than a Maryland bridge. The downsides of this option included: 

1. The removal of otherwise perfectly healthy tooth structure of No. 10 for no other reason but to replace No. 9 

2. It is challenging to achieve ideal aesthetics by treating only 2 teeth on one side of the smile/midline

3. The limited ability to improve the aesthetics of tooth No. 8 

4. The possibility to further compromise the already compromised tooth No. 10 

One potential saving grace of this option was that we would be removing tooth structure from a tooth, No. 10, which was already compromised and had a questionable long-term prognosis. If tooth No. 10 were to break, then it would probably need to be extracted, in which case we would benefit because now we would have sufficient room for an implant. 

Option 2: Placement of a conventional bridge from teeth Nos. 8 to 10 with a pontic on No. 9. I explained that in cosmetic dentistry, we always at least consider and discuss with the patient treating teeth symmetrically in the smile/on both sides of the midline for the best aesthetic outcome. For this reason, I also recommended a porcelain veneer for tooth No. 7. Downsides of this option included: 

1. The removal of otherwise perfectly healthy tooth structure from teeth Nos. 7, 8, and 10 for no other reason but to replace missing tooth No. 9 

2. The possibility to further compromise the already compromised tooth No. 10 (though far less compromise with this option than with option 1 since tooth No. 8 would also assist in supporting the pontic for No. 9)

The upsides of this option included:

1. Better prognosis than option 1 since tooth No. 8 would aid compromised tooth No. 10 in supporting missing tooth No. 9

2. This option would provide the best aesthetic outcome

3. With this option, we would have better control over the shape and aesthetics of No. 8

The family was told that if they were interested in this option, our next steps would be to work with my ceramist to complete a diagnostic wax-up to plan the case. Once that step was completed, we would be ready to start. We would prepare the teeth for the restorations and place temporary restorations, which would be indicative of the final result (based on the diagnostic wax-up). Carson would wear these temporary restorations for approximately 6 weeks while the laboratory fabricated the final porcelain restorations. This would give him time to ensure he was pleased with the anticipated final result. The family was advised that the final restorations might have to be returned to the lab for modifications if the shade match was not ideal. In this case, the temporaries would be worn longer than 6 weeks. Once the final restorations were in place, it would also be necessary to make new retainers. 

The family was told that this was quite a bit more involved than we had previously discussed (certainly more involved than a Maryland bridge); however, I did not want Carson to continue suffering the consequences of failure of a front tooth any longer at such a critical social and physical developmental time in his life. The previous experience with a Maryland bridge was hard on Carson and the family, and we didn’t want to repeat that experience for him. Again, it was reinforced that this should be more successful than the Maryland bridges that had already failed for Carson. This was a critical time in Carson’s formative years, and I felt he deserved the option of a stable, good-looking smile he could feel confident in.

To be sure all of the options were understood, we did discuss the option of making a removable acrylic partial (flipper). They had no interest in considering this option (and in all honesty, neither did I). 

IMPLEMENTING THE PLAN

Ultimately, the family chose the conventional 3-unit bridge from teeth Nos. 8 to 10 and a porcelain veneer for tooth No. 7 for the best symmetry. We whitened Carson’s teeth first using the Zoom! in-office whitening system (Philips Oral Healthcare). We completed the diagnostic wax-up via typical analog PVS impressions and stone models with Treasure Dental Laboratory in Idaho Falls, Idaho. Once the diagnostic wax-up was completed, No. 7 was prepared for a conservative porcelain veneer, and teeth Nos. 8 and 10 were prepared for an all-porcelain bridge using a clear suck-down matrix of the wax-up to ensure prep design supported the planned restorations. Lithium disilicate (IPS e.max [Ivoclar]) porcelain restorations for the case were planned, and the case was temporized using the spot-etch and bond/shrink-wrap technique using a putty matrix of the diagnostic wax-up. (Products used for the temporary restorations included Prime&Bond elect Universal Dental Adhesive [Dentsply Sirona] and Integrity monomethacrylate/polymethacrylate provisional material [Dentsply Sirona] in bleach shade). The challenging part aesthetically was addressing the tipping of tooth No. 10. The contours on the distal of the bridge were not ideal but were the best we felt we could achieve based on the natural tooth position present underneath the bridge. Treasure Dental Laboratory did an amazing job on this case. 

Prior to and during treatment, it was noted that Carson’s muscles for smiling (oribicularis oris, risorious, LLSAN, etc) appeared to be somewhat atrophied. We could barely move the lips out of the way to take photos of the preps for the laboratory and when finishing the provisionals. This is the explanation for the less-than-ideal photos seen here of the preps. Note how conservative these preps were, especially theminimally prepared lingual surfaces. There is just a finish line at the gingival aspect of the lingual surfaces and smoothed lingual surfaces to blend them into the preparations. There was no need for substantial lingual preparation because of the patient’s overjet (Figures 13 and 14.)

Figure 13.

Figures 13 and 14. Conventional bridge preps for IPS e.max (Ivoclar) teeth Nos. 8 and 10 and IPS e.max porcelain veneer prep No. 7; the lingual surfaces of Nos. 8 and 10 were minimally prepared since the patient had overjet.

The transformation was immediate. When Carson came in for us to check the provisionals, the hoodie was still there, but you can see in the photos his attempts to smile for the first time in many years (Figure 15). This was definitely the first time we had ever seen even an attempt at a smile from Carson. 

Figure 15. Carson wearing his provisionals and still wearing his hoodie but obvi- ously attempting to smile.

Figure 16.

Figure 17.

Figures 16 to 18. Final IPS e.max restorations: porcelain veneer for tooth No. 7 and a 3-unit bridge for Nos. 8 to 10. Gone is the hoodie, and already Carson is building his atrophied smile muscles.

The completed IPS e.max restorations are seen in Figures 16 to 18. It is notable that the hoodie is gone, and the smile muscles are only growing stronger. In person, he was bubbly to the point of being excited. My reward was the fact that he hugged me instead of barely looking at me and giving me one-word answers. And he told me he had even asked a girl to his upcoming homecoming dance.

FINAL COMMENTS

Was this the hardest case technically? No. Was it super sophisticated? No. Was it the most aesthetic case you’ve ever seen in your professional life? No. Will some dentists comment about doing a 3-unit anterior bridge for a 16-year-old? Yes! But did the treatment provided substantially change a person’s life? Yes! Did seeing his life change for the better change my life for the better? One thousand times, yes! 

It is hard sometimes to keep going strong after 20 years at it. Dentistry is hard on many days. Cases like these are what keep me going. I hope you enjoyed reading about it. I encourage us all to “think outside the box” when the Carsons of the world land in our offices—no one wants to do a 3-unit bridge and a veneer in a 16-year-old. But I do believe this was the right answer in this case. I am certain Carson and his family agree. I hope you are inspired to think outside of the box should a Carson ever walk into your office!F  

ABOUT THE AUTHOR

Dr. Hoppe earned her BA in biology with a minor in chemistry from Texas A&M University and her DDS degree from the University of Texas Health Science Center in Houston. She was awarded the prestigious Fellowship in the AGD in 2012. Dr. Hoppe owned and operated a small dental practice in Austin, Texas, for 10 years. Upon relocation to Florida, Dr. Hoppe stepped into the role of dental director for the Children’s Volunteer Health Network, treating more than 1,000 children and providing more than $300,000 in free dental care for underprivileged children in Walton and Okaloosa Counties. She simultaneously opened her state-of-the-art comprehensive care dental office, 30A Smiles, which she co-owns in the Inlet Beach area. She can be reached via her Instagram handle, @drlindseyhoppe, or at her website, 30asmiles.com.

Disclosure: Dr. Hoppe reports no disclosures.

In functional dentistry, structural integrity is directly linked to clinical performance and long-term prognosis. Anterior teeth are often the most susceptible first points of impact in traumatic dental incidents. Both direct and indirect modes of trauma and their sequelae must be considered. This extends beyond the initial salient structure loss, if any, and points to the long-term implications of a simple root canal treatment, particularly if the patient presents at a young age with hypertrophic pulp anatomy. While endodontic therapy is highly predictable, the restorative support and function of residual tooth structure is not. In individuals featuring existing Class III caries or restorations, further compromise of this structure augments the impact on the residual elastic modulus of the weakened tooth, which has a role in anterior guidance during dynamic occlusion function. To add insult to injury, there are often hemoglobin-derived residues present in the lumen of dentinal tubules, typically in the form of hemosiderin, which is dark in value and, thus, impacts the overall perceived brightness of the tooth. Aesthetic concerns often emotionally outweigh functional considerations in these individuals, the latter of which must not be overlooked when deciding the course of ideal treatment. 

Functional aesthetics is a discipline with a focus on restoring functional parameters as a priority with a supplemental goal of enhancing the cosmetic appearance of the dentition.

Not all surfaces of an anterior tooth are equal in resisting bending or moment forces during function. Magne and Tan¹ measured a 23% and 34% reduction in incisor flexural rigidity with moderate to aggressive Class III preparations. After bonded composite restorations were placed, 85% of the original crown stiffness was recovered. In the same study, a conservative endodontic access reduced the coronal stiffness by an insignificant margin in contrast to an aggressive endodontic access preparation, whereas a veneer preparation resulted in a 91% decrease in flexural integrity. The idea that anatomy imparts resistance to harmful forces during function has a direct correlation to areas with a localized bulk of enamel. On an incisor, these areas comprise the cingulum, lingual and facial marginal ridges, and facial cervical convexity.² Finite element analysis studies found that compressive stresses, which are normally low and countered well in an intact tooth, are magnified up to an additional 150 MPa when the facial enamel is removed. The concept of minimizing enamel reduction in the cingulum is extended to bonded indirect veneer design, where margin designs chamfered on the palatal aspect extending in the area of the cingulum exhibited the highest tensile stresses. A veneer with a palatal butt joint or one with minimal overlap showed negligible tensile or even compressive stresses on the interface with tooth structure.³ It is always the aim to increase the height of natural ferrule on the palatal aspect, as this can significantly elevate the fracture resistance of preparations.^4,5 A 1-mm increase in coronal dentin height has been established to double the fracture toughness of an endodontically treated tooth.⁶

From a naturomimetic standpoint, bonded porcelain restorations are best poised to replace missing enamel due to a closely matched elastic modulus relative to composite resin. This concept extends to the placement or replacement of Class III restorations in conjunction with veneer design. When a veneer is bonded in place and a significant Class III composite restoration is cured, the contractile stress from polymerization stresses the veneer-tooth interface. When thermal loads are applied, the designs with the lowest stresses are reflected in the variations with the maximal replacement of interdental composite by porcelain (ie, porcelain overlap).⁷ Hence, palatal prep-through designs for restorations with moderate to large Class III restorations are ideal for function. 

CASE REPORT

A healthy, ASA I, 22-year-old female presented to my practice, traveling from a distance for functional and aesthetic enhancement of teeth Nos. 8 and 9 (Figure 1). These teeth had been involved in dental trauma at an early age and thus had both been endodontically treated. The access cavities noted were excessive in size and linked to the presence of large Class III composite restorations proximally. The patient was concerned about the progressive darkening of the teeth. Clinically, her facial enamel shell was intact. Discussions revolved around the functional strength of the teeth and, in particular, the current compromise due to structure loss in critical areas. The patient was interested in composite veneers for the teeth, but as they were ideal in a buccopalatal location, additive resin layering would have resulted in prominent teeth in buccoversion, away from the ideal curve of the arch. The strategy for treatment involved lifting the color value of the teeth with a combination of internal bleaching and restorative effects to allow minimal preparation on the facial surfaces. In this way, a maximal volume of residual enamel and dentin would be preserved, maximizing the residual prognosis of the teeth. Instructions were given to the patient to return to her dentist for internal bleaching of the teeth before the palatal restorations and access cavities were restored with composite resin. 

Figure 1. Preoperative situation.

The patient returned to the practice 4 months later, with the internal bleaching result still exhibiting a lower value relative to the adjacent, healthy teeth. The patient reported that this was the final effort by the dentist and that she did not want to continue internally bleaching. The patient was warned about the potential need to compromise a greater volume of enamel with possible dentin exposure in order to effect a lift in value, a procedure that would compromise the flexural modulus of the tooth further. 

The desired facial composite shades were selected prior to any dehydration of the teeth (Figure 2). The patient was anesthetized, and a rubber dam affixed with floss ties (Figure 3). Endodontic access cavities were opened, and old Class III restorations were excavated, revealing a severe extent of missing pericervical dentin and axial wall structure (Figure 4). The gutta-percha was reduced to crestal level before sealing the orifice aspects using Fuji VII white (GC America) (Figure 5). After setting, the palatal aspect was micro air abraded using a 27-µm aluminum oxide powder at 2 bar of pressure (PrepStart [Zest Dental Solutions]). A total-etch adhesive approach was utilized (OptiBond Solo Plus [Kerr Dental]) before the buccal-facing surface internally was microlayered with a white opaque flowable composite (XL2, Herculite Ultra Flow Refill [Kerr Dental]) before more superficial layers were restored using micro-layers of A2 GrandioSO flowable (VOCO) (Figure 6). The residual facial wall was now as “white” as possible, with the value restoratively lifted. The shade exhibited increased opacity, likely due to the visibility of the white opaque material against the thin facial wall, with less depth of translucency relative to an intact tooth (Figure 7). The palatal anatomy was reconstructed focusing on initially layering the palatal marginal ridges and ensuring a natural convexity in their design. A single shade of A2 (GrandioSO) was utilized due to its exceptional flexural strength and wear resistance (Figure 8). The cingulum was completed next, along with secondary anatomy in the region, striving to re-create the bulk of cervical convexity with coronal extensions of the secondary lobes, also slightly convex and reaching into the palatal concavity.

Figure 2. Shade selection for direct composite.

Figure 3. Rubber dam isolation and pre-op views of facial and palatal aspects.

Figure 4. Removal of existing Class III restorations and palatal endodontic access. There was significant palatal axial surface and internal pericervical dentin deficiency.

Figure 5. Gutta-percha was reduced in apicocoronal height to a crestal level and sealed.

Figure 6. Opaque white flowable composite covered by A2 GrandioSO flowable (VOCO).

Figure 7. Appearance of the facial aspect after conservative contour reduction and micro air abrasion with 27-μm aluminum oxide.

Figure 8. Direct layered composite restorations (GrandioSO) on the palatal aspect striving to re-create natural areas of convexity to bolster residual flexural strength.

Figure 9. Photo denotes application of 33% orthophosphoric acid to the tooth. Note that the entire facial surface was etched and not only in this specific etch pattern (artistic merit).

The facial surface was lightly prepared (0.2 mm) to provide a minimal buccolingual volume for composite layering. After a total-etch adhesive approach (Figure 9 indicates the application of 33% orthophosphoric acid to the facioincisal aspect of the tooth, which was subsequently spread across the entire surface, not only in the pattern shown), the dentin, effect, and enamel shades were layered in typical fashion, and primary/secondary anatomy was established. The overall effect was a value-lifted, well-characterized composite veneer that was slightly opaque and high in value, which typifies the challenges with cases with a structural or positional compromise (Figures 10 to 16). 

Figure 10. Freehand application of composite to reconstruct the lingual axial wall.

Figure 11. Lingual shelves complete. Interproximal clearance was ensured at every step.

Figure 12. Composite layering to re-create internal dental opacity, incisal translucency, incisal halo, and maverick effects (white).

Figure 13. Establishment of primary anatomy.

Figure 14. Secondary anatomy was established, and the vertical axial enamel fold was created and polished to a high shine.

Figure 15. Immediate postoperative result, showing increased opacity relative to the adjacent teeth.

Figure 16. Immediate post-op result showing increased opacity relative to the adjacent teeth and limitations in creating simultaneous depth of translucency and value/brightness change with a limited layering depth.

DISCUSSION

The goal of biomimetic dentistry is the re-creation of missing tooth structure in its attendant proportions and composition. This case featured central incisors with a severe paucity in structure, particularly on the palatal aspect, which is the area most responsible for the flexural resistance of an intact tooth. Elements that are critical for reconstruction of this area are a dentin-like and an enamel-like restorative material. Ideally, the elastic modulus of dentin, depending on if it’s peri-pulpal, peritubular, or intertubular, ranges from 5 to 30 GPa.⁸ It is best matched to composite resins, the bulk moduli of which range from 12.79 to 22.43 GPa, with a positive correlation noted between flexural modulus and filler volume fraction.⁹ From a biomimetic standpoint, the modulus of elasticity of proposed direct restoratives can thus even be matched with lower flexural modulus subtypes for deep dentin and higher modulus variants for superficial dentin. The advent of fiber-reinforced composite resin materials in the last decade now allows modern composite resins to have elevated fracture toughness that approximates or exceeds that of native dentin relative to regular composite. This is beneficial in minimizing the risk of crack propagation in structurally compromised teeth. Glass fiber-reinforced composites need to be contained internally via a closed sandwich technique as ambient moisture may be wicked internally into the restoration, accelerating hydrolytic degradation. Although not utilized in this specific case, the use of glass fiber-reinforced composites would have allowed a bolstering of residual tooth structure and, by increasing the fracture toughness, would have potentially biased a coronal fracture in a more favorable, reparable manner. 

Idealizing the value and chroma of the teeth prior to composite layering is the Achilles heel of this case. Had the value been corrected fully via internal bleaching, the need to use overly white and opaque restorative materials would have been avoided, along with the minimization of the need to reduce facially. This would have translated into restorations that exhibited a greater depth of translucency—indeed, invisible restorations. This case demonstrates what is possible adherent with what limitations exist using modern direct restoratives in the reconstruction and aesthetic enhancement of severely structurally compromised teeth.

It is needless to say that a bonded indirect solution may have added greater flexural support to the residual tooth structure, but given the patient’s age and financial priorities, a direct option was the most feasible at the time. The direct restorative material chosen, GrandioSO, ranks amongst the highest in flexural strength and elastic modulus in composite materials today. Indeed, the flexural strength of 187 MPa exceeds that of native dentin (165.6 MPa), and the elastic modulus is rated at 16.65 GPa (average dentin ranges from 16.55 to 18.62 GPa). Such super composites allow greater confidence in large-volume direct reconstructions, especially in cases where minimal invasion is sought. It is critical to reconstruct both facial and palatal anatomy with materials that best match the corresponding missing layers of tooth structure for maximal prognosis and predictable performance.

REFERENCES

1. Magne P, Tan DT. Incisor compliance following operative procedures: a rapid 3-D finite element analysis using micro-CT data. J Adhes Dent. 2008;10(1):49-56.  

2. Magne P, Versluis A, Douglas WH. Rationalization of incisor shape: experimental-numerical analysis. J Prosthet Dent. 1999;81(3):345–55. doi:10.1016/s0022-3913(99)70279-9 

3. Magne P, Douglas WH. Design optimization and evolution of bonded ceramics for the anterior dentition: a finite-element analysis. Quintessence Int. 1999;30(10):661–72.   

4. Milot P, Stein RS. Root fracture in endodontically treated teeth related to post selection and crown design. J Prosthet Dent. 1992;68(3):428–35. doi:10.1016/0022-3913(92)90405-y 

5. Zhang YY, Peng MD, Wang YN, et al. The effects of ferrule configuration on the anti-fracture ability of fiber post-restored teeth. J Dent. 2015;43(1):117–25. doi:10.1016/j.jdent.2014.10.003 

6. Sorensen JA, Engelman MJ. Ferrule design and fracture resistance of endodontically treated teeth. J Prosthet Dent. 1990;63(5):529–36. doi:10.1016/0022-3913(90)90070-s 

7. Magne P, Douglas WH. Interdental design of porcelain veneers in the presence of composite fillings: finite element analysis of composite shrinkage and thermal stresses. Int J Prosthodont. 2000;13(2):117–24.  

8. Kinney JH, Balooch M, Marshall SJ, et al. Hardness and Young’s modulus of human peritubular and intertubular dentine. Arch Oral Biol. 1996;41(1):9-13. doi:10.1016/0003-9969(95)00109-3

9. Masouras K, Silikas N, Watts DC. Correlation of filler content and elastic properties of resin-composites. Dent Mater. 2008;24(7):932–9. doi:10.1016/j.dental.2007.11.007

ABOUT THE AUTHOR

Dr. Tam received her DDS degree and completed her general practice residency in pediatric dentistry at the University of Western Ontario and the University of Toronto, respectively. Her practice has a focus on restorative and cosmetic dentistry. She is well-published in both the local and international dental press, writing articles, reviewing submissions, and developing prototype products and techniques in clinical dentistry. She frequently and continually lectures internationally. Dr. Tam is the immediate past chairperson and director of the New Zealand Academy of Cosmetic Dentistry. She is one of 2 dentists in Australasia who are board-certified, accredited members of the American Academy of Cosmetic Dentistry. Moreover, she maintains Fellowship status with the International Academy for Dental and Facial Esthetics. She sits on the board of Smiles for the Pacific, an educational trust and charity that aims to expand professional dentistry services across the South Pacific region. She can be reached at clarence.tam@gmail.com.

Disclosure: Dr. Tam receives financial compensation from VOCO America. 

Amelogenesis imperfecta is a collection of genetic conditions that most often presents intraorally with generalized hypomineralization. Treatment requires a multidisciplinary approach and close professional collaboration. Although treatment methods vary, most patients initially require anterior composite restorations and posterior stainless steel crowns on high-risk teeth to allow for healthy psychosocial development and posterior function. Following growth and development, patients often require full-arch restorations in conjunction with crown lengthening surgery since hypomineralization and wear minimize available tooth structure. This case report documents the multidisciplinary treatment of a patient suffering from amelogenesis imperfecta and highlights the significance of interdisciplinary collaboration.

Amelogenesis imperfecta is an uncommon genetic condition affecting the enamel. More specifically, it causes hypomineralization or hypoplasia.¹ Epidemiologically, the disease prevalence ranges from 1:700 to 1:14,000.^2,3 The different classifications of the disease are organized either by clinical presentation or genetic mutation. Alterations to the secretory stage of tooth development can cause amelogenesis imperfecta via mutations in AMELX (X-linked) or ENAM (autosomal dominant) genes. Likewise, mutations in MMP20 and LKL4 genes (autosomal recessive) result in softer enamel.⁴ Amelogenesis imperfecta affects enamel of all teeth, and hypoplasia is often associated with discoloration and hypersensitivity.¹ Treatment of these patients is very challenging since restorations are required on every tooth. Moreover, the quality of the existing tooth structure can complicate the quality of final restorations as inadequate etching can result in less retention and more leakage. Coronal restorations in patients with amelogenesis imperfecta had a survival rate of 50% compared to a survival rate of 80% in patients with normal enamel.⁵ A conservative treatment option may include direct resin restorations, but this choice may only be a transitional treatment until patients finish growth.⁶ More often, full-coverage restorations are necessary for proper restoration and can be metal, stainless steel, ceramic, or porcelain-fused-to-metal.⁷ Full-coverage restorations in patients with amelogenesis imperfecta are predictable and comparable to full-coverage restorations placed in healthy patients.⁵ Because of the wear, most full-mouth cases require crown lengthening surgery in order to provide adequate tooth structure.⁸ Restoring and treating patients with amelogenesis imperfecta is a complicated task that requires an interdisciplinary approach and a comprehensive plan.

CASE REPORT

A 16-year-old healthy male presented to the Rutgers School of Dental Medicine with the following chief complaint: “I have a lot of sensitivity, and I want to fix my smile.” The patient was diagnosed with amelogenesis imperfecta during childhood and received composite restorations in the anterior teeth and stainless steel crowns on the permanent first molar teeth as a provisional means to restore the dentition prior to completion of growth.⁶ The patient had a history of irregular care over the last several years. His mother stated that her 16-year-old son was reluctant to smile, particularly around his peers in school. The clinical examination revealed defective enamel with dentin exposure, yellow discoloration, tooth sensitivity, and dental caries (Figures 1 to 3). The premolar teeth had short clinical crowns and radiographically revealed large pulp horns. The maxillary and mandibular second molars were covered partially with keratinized mucosa, indicating that passive eruption may not yet have been completed. The maxillary right second molar was completely covered by soft tissue and was radiographically shown to have coronal tooth resorption, called intracoronal resorption. The maxillary arch was oval in shape and exhibited slight constrictions, particularly in the premolar regions. Occlusal examination showed that there was a slight discrepancy between centric relation and maximum intercuspal position with posterior teeth interferences in all excursive movements. Due to the extent of the enamel defects, there was occlusal attrition of the premolars. This led to supra-eruption of the premolar teeth and maxillary canines, causing a reverse smile-line and large gingival display in the maxillary premolar region on the full smile. Although he presented with generalized occlusal attrition, there was no loss of vertical dimension due to the compensatory dentoalveolar movement of the premolar teeth and the presence of stainless steel crowns on the first molar teeth. Radiographically, the coronal portions of the teeth appeared to have a thin layer of enamel, a typical phenomenon of hypoplastic amelogenesis imperfecta. Bite-wing and periapical radiographic films indicated that the pulp horns of the mandibular premolars were close to the external occlusal surfaces of the teeth (Figure 4). Based on the clinical and radiographic findings, a diagnosis of amelogenesis imperfecta was made. This is associated with a thin or no enamel layer (hypoplastic teeth), dental caries, defective composite restorations, occlusal plane discrepancy, occlusal interferences, and unerupted third molar teeth. The patient was treatment planned for a full-mouth rehabilitation with full-coverage restorations. The goals of treatment were to protect the teeth, reduce teeth sensitivity, and restore normal tooth form, function, and aesthetics. The prognosis for the teeth was favorable except for the maxillary right second molar, which was planned for extraction. No implant was planned at this stage since there were occlusal contacts between teeth Nos. 3 and 31, which will maintain the tooth spatial position of tooth No. 31. However, the patient was informed to replace the missing tooth in the future if needed. Because involving third molars in the treatment would complicate the case, the decision was made to extract them at the early stage of the treatment even though they were not yet erupted.

Figure 1. Preoperative frontal view. The patient presented with anterior composite restorations, generalized hypoplasticity, and posterior stainless steel crowns.

Figure 2. Pre-op occlusal view of the maxillary arch.

Figure 3. Pre-op occlusal view of the mandibular arch.

Figure 4. Full-mouth series illustrating extensive mineralization defects.

Figure 5. Mounting and wax-up at increased vertical dimension, which was necessary due to extensive wear.

Figure 6. Frontal view of provisional restorations at increased vertical dimension with polymethylmethacrylate.

Figure 7. Occlusal view of the full-arch mandibular temporary prosthesis with composite on second molars to hold the vertical position of the teeth.

Figure 8. Crown lengthening was performed for maxillary and mandibular posterior teeth. Pre-op photograph of the right posterior sextant.

In order to ensure proper delivery of care, an interdisciplinary approach, including prosthetic and periodontal collaboration, was required. Prior to treatment planning, irreversible hydrocolloid impressions (Jeltrate [Dentsply Sirona]) of the maxillary and mandibular arches were made to generate diagnostic stone casts. These casts were mounted in centric relation with a face-bow transfer on a semi-adjustable articulator (Hanau Wide Vue [Whip Mix]). A diagnostic wax-up was then constructed. Since the teeth exhibited large pulp horns, a conservative approach was made to open the vertical dimension by 2 mm in the premolar area and select a restorative material that would accept a minimum occlusal thickness yet restore aesthetics and function. In this case, all-ceramic lithium disilicate material was selected for the anterior and posterior teeth. Full-metal gold restorations were planned for restoration of the second molar teeth to the required restorative space. The first phase of the treatment involved caries control and the extraction of the third molars and the maxillary right second molar. This improved accessibility to the distal surfaces of the second molars. Initially, all teeth were prepared except for the second molars. The patient was provisionalized in the new vertical dimension of occlusion with full-arch splinted fixed temporaries made of milled PMMA resin material relined with chairside auto-polymerized resin material (ALIKE Temporary Crown and Bridge Resin [GC America]) (Figures 5 and 6). Flowable composite (Filtek Supreme Flowable Restorative [3M]) was added to the occlusal pit and fissure of the mandibular second molars to maintain the vertical position of these teeth until the crown lengthening was done, and these teeth were prepared to receive provisional crowns (Figure 7). The provisional restorations and increased vertical dimension were tested for 4 weeks. During this time, there were no TMD symptoms or difficulty in speech or swallowing reported by the patient. After confirming the patient’s comfort, he was seen in the postgraduate periodontics department for crown lengthening of the maxillary arch and mandibular posterior teeth. Prior to crown lengthening, surgical guides were fabricated on models depicting the desired level for the soft tissue. With the aid of the surgical guide, crown lengthening was completed to ensure proper space for biologic width and adequate retention and resistance form (Figure 8). The crown lengthening procedure entailed a full-thickness flap elevated to the mucogingival junction and a split-thickness flap apical to the mucogingival junction (Figure 9). This allowed precise apical repositioning of the flap at the crest following ostectomy and osteoplasty via 4-0 chromic gut sutures (FS2 Ethicon). Also, the amount of keratinized gingiva was maintained (Figure 10). Immediately after crown lengthening and before the flap was sutured, the second molar teeth were prepared, and the temporary crowns were fabricated to ensure the desired preparation design was achieved. After appropriate healing (Figure 11), the finish line margins of the teeth preparations were refined, and the patient received a second set of provisionals to ensure proper aesthetics and function (Figure 12). Prior to final impressions, the patient requested the treatment of pigmented gingiva, which was accomplished by using the Nd:YAG laser (PerioLase MVP-7 [Millennium Dental Technologies]). Maxillary and mandibular frenectomies were performed at the same time (Figure 13). The Nd:YAG laser has a 1,064-nm wavelength, which highly absorbs melanin and pigment, optimizing the depigmentation process.

Figure 9. Intraoperative photograph illustrating full-/split-flap elevation and osseous recontouring with a surgical guide to allow for biologic width.

Figure 10. Immediate postoperative photograph of an apically positioned flap following the crown lengthening procedure.

Figure 11. Post-op photograph of one sextant of the crown lengthening procedure.

Figure 12. Post-op photograph after relining provisional restorations.

Figure 13. Intraoperative photograph illustrating the use of an Nd:YAG laser for maxillary and mandibular depigmentation and frenectomies.

RESULTS

Figure 14. Post-op photograph illustrating the result of the depigmentation and frenectomy procedure.

Following healing, the patient was pleased with the aesthetic result (Figure 14). Four months after crown-lengthening surgery and laser therapy, intrasulcular preparations were impressed for delivery of the final prosthetics (Figures 15 to 19). The patient reported the disappearance of teeth sensitivity at the end of the treatment and during followup visits. Moreover, the patient received an aesthetic and functional result (Figures 20 to 22) that restored his functionality and psychosocial health as compared to his initial presentation. Regular maintenance is very crucial for long-term successful treatment. Therefore, he is being placed on a meticulous maintenance schedule of every 3 to 4 months. Oral hygiene has been continually reinforced, and the patient has been placed on PreviDent 5000 (Colgate) and Booster Toothpaste (Colgate).

Figure 15. Frontal view following final delivery of the all-ceramic lithium disilicate restorations.

Figure 16. Right lateral view following final delivery of the all-ceramic lithium disilicate restorations.

Figure 17. Left lateral view following final delivery of the all-ceramic lithium disilicate restorations.

Figure 18. Maxillary occlusal view following final delivery of the all-ceramic lithium disilicate restorations and full-coverage gold restoration of the second molar.

Figure 19. Mandibular occlusal view following final delivery of the all-ceramic lithium disilicate restorations and full-coverage gold restoration of the second molars.

Figure 20. Frontal extraoral photograph of smile following interdisciplinary therapy and full-mouth rehabilitation.

Figure 21. Lateral extraoral photograph at rest following interdisciplinary therapy and full-mouth rehabilitation.

Figure 22. Lateral extraoral photograph of smile following interdisciplinary therapy and full-mouth rehabilitation.

DISCUSSION

Management of these patients is accomplished in 3 phases: temporary, transitional, and permanent.⁹ The temporary phase of care addresses the primary and mixed dentition, which requires a combination of composite restorations for aesthetic concerns and stainless steel posterior restorations. The transitional phase entails monitoring the patient’s growth and restorative status until the permanent dentition has completed eruption and the patient has ceased active growth. At this time, the patient enters the permanent phase, where a multidisciplinary team provides full-mouth rehabilitation. This case report illustrates the prosthetic and periodontal treatment of a patient entering the permanent phase of care. As Chen et al⁹ discuss, the patient was properly diagnosed at an early age when he received stainless steel posterior crowns to prevent caries progression and composite anterior restorations. Note that the direct anterior restorations were delivered primarily to improve psychosocial status. Studies regarding amelogenesis imperfecta patients indicate that without aesthetic restorations, their self-esteem decreases, and social dysfunction increases.¹⁰ Both indirect and direct restorations have been reported to restore teeth in patients with amelogenesis imperfecta. While guidelines to treat such patients are not yet available, indirect restorations have shown more predictable results when compared to direct restorations.¹¹ Previous research showed that the enamel and dentin in patients with amelogenesis imperfecta are associated with changed properties, which explains why direct restorations have a higher failure rate than indirect restorations. All-ceramic lithium disilicate material was chosen to restore the majority of the teeth in this case. Not only does lithium disilicate material provide excellent optical properties, but it also allows for minimal tooth preparation and possesses acceptable strength and longevity when bonded to tooth structure. Previous reports showed that all-metal, full-gold material would be the material of choice when restoring second molar teeth because of the minimal thickness needed and high fracture strength. 

To ensure high longevity of the restorations, retentive grooves were added to the teeth preparations to improve the retention and resistance form. Although the patient presented with limited interocclusal space distance (2 mm), the vertical dimension of occlusion was opened by 1.5 mm, and another 0.5 mm was achieved by guiding the patient to CR position. Such an increase has been reported to be safely introduced when certain considerations are taken.^12,13 In addition, the temporary crowns were tested in the patient’s mouth for several months without any signs and symptoms reported by the patient. 

One of the main advantages of opening the VDO in such cases is to provide a space for restorative material so that minimum occlusal reduction is needed. This is important since the pulp horns of the mandibular premolars appeared close to the occlusal surfaces due to the patient’s age and the thin enamel layer. Other advantages include maintaining tooth vitality, preserving tooth structure, reducing the amount of adjunctive surgery, and correcting minor irregularities in the occlusal plane.¹² Special attention was paid to the thickness of the existing enamel on the tooth surfaces during the examination process. Since there was limited thickness evident clinically, the wax-up was done using an additive approach. Consequently, minimal reduction of the axial walls was needed during tooth preparation.

Growth of the jawbone vertically and horizontally may initiate some spaces between the teeth. However, migration of the teeth should maintain biological and functional contacts. Moreover, with proper margin placement and good restorative material selection, future apical migration of the gingiva in the aesthetic zone should present as a minimal aesthetic concern. Finally, the patient avoided endodontic therapy even though the prevalence of endodontic complications reported ranges between 1% to 3% in patients with amelogenesis imperfecta.^14,15 Orthodontic intervention is common due to malocclusion, open bites, delayed tooth eruption, missing teeth, and pathological crown and root formation.^9,16 Orthodontic treatment was presented to the patient, and he declined due to the time and cost of the treatment. Since he presented with mild orthodontic issues, the case was successfully managed with proper planning and meticulous periodontal and restorative treatment.

CONCLUSION

This case report discusses one example of amelogenesis imperfecta management. Proper care for patients with this condition is often accomplished in 3 phases, with the final phase requiring full-mouth rehabilitation. This publication highlights the need for interprofessional collaboration and illustrates various challenges that may occur during treatment. It further illustrates the positive impact proper treatment can have on a patient’s social, functional, and aesthetic well-being.

ACKNOWLEDGMENTS

A special thank you to Dr. Neal Lehrman for his guidance with the laser depigmentation therapy. The case was delivered through the Rutgers School of Dentistry Postgraduate Program and made possible with the associated faculty and staff. 

REFERENCES

1. Crawford PJ, Aldred M, Bloch-Zupan A. Amelogenesis imperfecta. Orphanet J Rare Dis. 2007;2:17. doi:10.1186/1750-1172-2-17

2. Bäckman B, Holm AK. Amelogenesis imperfecta: prevalence and incidence in a northern Swedish county. Community Dent Oral Epidemiol. 1986;14(1):43-7. doi:10.1111/j.1600-0528.1986.tb01493.x

3. Witkop CJ, Sauk JJ. Heritable defects of enamel. In: Stewart RE, Prescott GH (Eds.), Oral facial genetics. Mosby;1976:151-226.

4. Hu JC, Chun YH, Al Hazzazzi T, et al. Enamel formation and amelogenesis imperfecta. Cells Tissues Organs. 2007;186(1):78-85. doi:10.1159/000102683

5. Pousette Lundgren G, Dahllöf G. Outcome of restorative treatment in young patients with amelogenesis imperfecta. A cross-sectional, retrospective study. J Dent. 2014;42(11):1382–9. doi:10.1016/j.jdent.2014.07.017. Erratum in: J Dent. 2015;43(2):295. 

6. Sabatini C, Guzmán-Armstrong S. A conservative treatment for amelogenesis imperfecta with direct resin composite restorations: a case report. J Esthet Restor Dent. 2009;21(3):161–9; discussion 170. doi:10.1111/j.1708-8240.2009.00258.x

7. Sabandal MM, Schäfer E. Amelogenesis imperfecta: review of diagnostic findings and treatment concepts. Odontology. 2016;104(3):245–56. doi:10.1007/s10266-016-0266-1

8. Akin H, Tasveren S, Yeler DY. Interdisciplinary approach to treating a patient with amelogenesis imperfecta: a clinical report. J Esthet Restor Dent. 2007;19(3):131–5; discussion 136. doi:10.1111/j.1708-8240.2007.00083.x 

9. Chen CF, Hu JC, Bresciani E, et al. Treatment considerations for patient with Amelogenesis Imperfecta: a review. Braz Dent Sci. 2013;16(4):7-18. doi:10.14295/bds.2013.v16i4.904

10. Coffield KD, Phillips C, Brady M, et al. The psychosocial impact of developmental dental defects in people with hereditary amelogenesis imperfecta. J Am Dent Assoc. 2005;136(5):620–30. doi:10.14219/jada.archive.2005.0233

11. Strauch S, Hahnel S. Restorative treatment in patients with amelogenesis imperfecta: a review. J Prosthodont. 2018;27(7):618–23. doi:10.1111/jopr.12736

12. Abduo J. Safety of increasing vertical dimension of occlusion: a systematic review. Quintessence Int. 2012;43(5):369–80. 

13. Fabbri G, Sorrentino R, Cannistraro G, et al. Increasing the vertical dimension of occlusion: a multicenter retrospective clinical comparative study on 100 patients with fixed tooth-supported, mixed, and implant-supported full-arch rehabilitations. Int J Periodontics Restorative Dent. 2018;38(3):323–35. doi:10.11607/prd.3295

14. Lindunger A, Smedberg JI. A retrospective study of the prosthodontic management of patients with amelogenesis imperfecta. Int J Prosthodont. 2005;18(3):189–94. 

15. Pousette Lundgren G, Morling Vestlund GI, Trulsson M, et al. A randomized controlled trial of crown therapy in young individuals with amelogenesis imperfecta. J Dent Res. 2015;94(8):1041–7. doi:10.1177/0022034515584385

16. Arkutu N, Gadhia K, McDonald S, et al. Amelogenesis imperfecta: the orthodontic perspective. Br Dent J. 2012;212(10):485–9. doi:10.1038/sj.bdj.2012.415 

ABOUT THE AUTHORS

Dr. Murayshed received his BDS degree from the King Saud University College of Dentistry, Riyadh, Saudi Arabia, in 2012. In 2021, he received his postgraduate specialty certificate in prosthodontics and earned a Master of Dental Sciences degree from the Rutgers School of Dental Medicine (RSDM). Currently, Dr. Murayshed is working as faculty in prosthetic dental sciences at Prince Sattam bin Abdulaziz University in Saudi Arabia. He can be reached at drmohammad1@hotmail.com.

Dr. Goldberg is a periodontist working in private practice in New Jersey. He received his DDS degree from Columbia University in 2018 and completed his periodontal residency at Rutgers University in 2021. During his postgraduate tenure, Dr. Goldberg presented at and moderated the Northeastern Implant Symposium, served as chief resident, received a degree from the Institute of Advanced Laser Dentistry, and was awarded the Michael J. Deasy Endowed Scholarship. He currently practices with his father, who is also an established periodontist. He can be reached at adamgoldberg2207@gmail.com. 

Dr. Howard Drew is a professor, a director of implantology, and the vice chairman of the Department of Periodontics at RSDM. He received his doctorate and degree in periodontics from RSDM. He has been awarded the RSDM Excellence in Teaching Award, Stuart D. Cook Master Educators Guild Award, and the prestigious AAP Educator Award. Dr. Drew was inducted into the American College of Dentists, and he was awarded the RSDM Alumni Association Decade (1980s) Award. He has more than 25 publications to his name and has lectured throughout the country. He was in full-time clinical practice for more than 25 years. He can be reached at drhjdrew@aol.com.

Dr. Alexander Drew is a maxillofacial prosthodontist with a private practice in Summit, NJ, limited to prosthodontics and restorative dentistry. He received his DMD degree from the University of Pennsylvania. After completing dental school, he earned a specialty certificate in prosthodontics and an MS degree from the Columbia University College of Dental Medicine, where he was the chief resident. He then completed a subspecialty fellowship in maxillofacial prosthetics and was awarded a certificate from Memorial Sloan Kettering Cancer Center. Dr. Drew is a member of the American College of Prosthodontics and the ADA. He is an Associate Fellow of the American Academy of Maxillofacial Prosthetics and an author to research publications in high-impact scientific journals. He can be reached at asdrew1@gmail.com.

Disclosure: The authors report no disclosures.

Milled/sintered materials like zirconia and IPS e.max (Ivoclar Vivadent) are the industry standard for crowns. But these materials have demonstrated accelerated wear on opposing dentition over time due to their greater hardness and abrasive nature compared to enamel. Alternative milled materials, such as IPS Empress (Ivoclar Vivadent), are often preferred due to their wear characteristics being more comparable to enamel, dentin, and composite. 

Three-dimensionally printed materials have seen increased usage in recent years in various prosthetic and restorative treatment areas, either fabricated at the lab or in-office. Novel 3D printed materials offer comparable mechanical performance to natural dentin and demonstrate comparable wear as natural tooth to natural tooth. A study was performed to evaluate SprintRay Ceramic Crown resin intraorally (in vivo) on 25 single posterior and anterior crowns over a period of 9 months. No failures, material fractures, or excessive wear were noted in the study crowns.  

When comparing various materials that may be utilized for a crown, flexural strength and flexural modulus need to be compared to dentin as the bulk of the tooth is dentin (Table 1). Following preparation, there could be minimal or no remaining enamel on the tooth. Additionally, the restoration is cemented or bonded to the dentin, replacing the enamel removed during preparation. Dentin has been reported to have a flexural strength of 150 to 250 MPa and a flexural modulus of 12 to 21 GPa.^1,2  

Table 1. Flexural strength and modulus of the SprintRay Ceramic Crown and various ceramic restorative materials compared to dentin.

Zirconia is a very strong material with a reported flexural strength of approximately 1,000 MPa when veneered with another ceramic³ and approximately 1,200 MPa when monolithic.⁴ A flexural modulus of 210 GPa has been reported for this material. Unfortunately, it has also been reported to increase wear on opposing teeth, which is dependent on the polish of the restoration and the patient’s bruxism habits.^5,6 If any adjustments are needed to adjust the occlusion, it is recommended that proper polishing is performed so that a rough area that may accelerate wear is not present.  

IPS e.max, a lithium disilicate glass ceramic, has become a common milled or sintered ceramic for crowns and other single-unit restorations. A flexural strength of 250 MPa and a flexural modulus of 80 GPa has been reported.⁷ Restorations made from this material may demonstrate wear on opposing dentition but less than zirconia. As the material is stiffer than dentin, a fracture may occur under heavy functional loading or in patients who brux. Pressed IPS e.max has been reported to have more issues than milled restorations of this material.⁸ The fracture resistance of fully crystallized lithium disilicate ceramic block materials is lower than their pre-crystallized counterparts. So the handling of the milled restorations during fabrication affects their fracture resistance and long-term survival.⁹ When the material has been subjected to aging, increased surface roughness and microstructure alterations have been observed. This may increase wear of the opposing dentition and also lead to fracturing of the crown material, especially when it is thin.¹⁰ 

IPS Empress, a leucite glass ceramic, has been in use prior to IPS e.max for single-unit restorations. A flexural strength of 150 MPa and a flexural modulus of 32 GPa has been reported.¹¹ As its mechanical properties are lower than IPS e.max, this material has been utilized to preserve surrounding dentition and minimize antagonist wear.  

Printed restorations have increasingly been replacing CAD-milled restorations over the past few years due to their easier fabrication process, with an annual growth of 20%.¹² Ceramic resins have been introduced to be used with printers as a more durable material for restorations than previously used print resins.

VarseoSmile Crown plus (BEGO), a ceramic-filled resin that is printed for permanent crowns, has a reported flexural strength of 116 MPa and a flexural modulus of 4.1 GPa, which is significantly lower than dentin.¹³ This mismatch of mechanical properties with dentin poses a significant risk of fracture in the long term, especially in those patients who brux. 

SprintRay Ceramic Crown is an FDA-cleared Class II resin for printing definitive crown restorations. The material has received FDA 510(k) approval for definitive and fixed full single anterior and posterior crowns, definitive partial crowns (onlays and crownlays), and single veneers. It may also be used to produce artificial teeth for dentures and monolithic full and partial dentures. This new, ceramic-filled 3D-print resin with improved strength values has a flexural strength of 136 MPa and a flexural modulus of 7.5 GPa due to its ceramic filler content (>51% by mass). The material is radiopaque for clear radiographic visibility. It possesses a high composite bond strength (the bond between the prosthetic and natural tooth surface), reducing the likelihood of secondary caries and failures. Low water absorption and water solubility provide a restorative material with a low tendency to discolor due to the liquids and foods the patient may eat. The resin is available in A1, A2, A3, B1, B3, C2, D3, and bleach shades to fit the patient shade values needed. 

CASE STUDIES

Case 1

A 25-year-old male patient presented with discomfort on tooth No. 2 (maxillary right second molar). A radiograph was taken, and decay was noted on the mesial with pulpal involvement (Figure 1). Endodontics was recommended, followed by a full-coverage crown. Following endodontic treatment, a resin-bonded core buildup was placed, and the tooth was prepared for a full-coverage crown. The preparation was scanned using Primescan (Dentsply Sirona) (Figure 2). The restoration was temporized, and the patient was appointed the next day to insert the final restoration. The scan data was imported into inLab CAD design software (Dentsply Sirona), and a full-coverage crown was designed for tooth No. 2 (Figure 3). The definitive crown was printed using SprintRay Ceramic Crown resin on the SprintRay 55 printer, then finished and polished, and then it was ready for insertion. The process was completed in less than 30 minutes, with the crown taking less than 10 minutes.

Figure 1. Pretreatment radiograph demonstrating caries on tooth No. 2 on the mesial with pulpal involvement.

Figure 2. Intraoral scan following crown preparation after endodontic treatment and core buildup on tooth No. 2.

Figure 3. Virtual crown to be printed on the SprintRay 55 printer and designed in inLab software (Dentsply Sirona).

As a comparison for the fit of the printed SprintRay Ceramic Crown, an IPS e.max crown was milled as well. Following the milling of both crowns, upon comparison, the exteriors looked similar, presenting as a polished restoration with matching anatomical detail (Figure 4). Yet, the intaglio surface of the printed SprintRay Ceramic Crown had a rougher surface than the IPS e.max crown, which would improve restoration retention to the preparation (Figure 5).

Figure 4. Views of the IPS e.max (Ivoclar Vivadent) milled crown (left) and printed SprintRay Ceramic Crown restoration (right).

Figure 5. View of the tooth side of the IPS e.max milled crown (left) and printed SprintRay Ceramic Crown (right). The printed ceramic resin restoration demonstrated a rougher surface on the printed crown, which improved cementation adherence to the crown material compared to the milled surface.

The patient returned the next day, the provisional crown was removed, and any residual temporary cement was cleaned up in preparation for the final restoration placement. Both crowns, the IPS e.max crown and the SprintRay Ceramic Crown, were tried in to check fit and marginal integrity. Marginal adaption and integrity was found to be identical between the 2 crowns. But the SprintRay Ceramic Crown restoration appeared to have better retention to the preparation when lateral light force was placed on the uncemented crowns. A periapical radiograph was taken of the SprintRay Ceramic Crown restoration on the preparation to check the fit, and good marginal adaption was noted (Figure 6, left). Multilink Primers A and B (Ivoclar Vivadent) were dispensed into a dish and mixed, then applied to the preparation. Monobond Etch & Prime (Ivoclar Vivadent) was applied to the intaglio surface of the SprintRay Ceramic Crown restoration, and the crown was filled with Multilink Dual-Cure Resin Cement (Ivoclar Vivadent) and then seated intraorally on the preparation. Excess resin cement was removed with a brush wetted with Monobond, and the restoration was light cured and then allowed to self-cure. Following curing, the margins were checked for residual cement, and the occlusion was checked. A periapical radiograph was taken to confirm restoration fit and adaption to the preparation (Figure 6, right). A post-insertion scan was taken with Primescan for study purposes (Figure 7).

Figure 6. Radiographs at the try-in of the printed SprintRay Ceramic Crown restoration (left) and following cementation (right).

Figure 7. Post-insertion intraoral scan of the SprintRay Ceramic Crown restoration on tooth No. 2.

Case 2 

A 66-year-old female patient presented for recall prophylaxis and had radiographs taken, which noted recurrent marginal decay on the PFM crown on tooth No. 29 (Figure 8). The patient was informed that the crown would require replacement due to the recurrent decay. The crown was removed following administration of local anesthetic, and the preparation was refined to remove the decay noted. The preparation was scanned using Primescan (Figure 9). The scan data was imported into the inLab CAD software, and the virtual crown was designed for printing (Figure 10). The definitive crown was printed using SprintRay Ceramic Crown resin on the SprintRay 55 printer, then it was finished and polished and ready for insertion (Figure 11).

Figure 8. Radiograph demonstrating marginal caries at the PFM crown on No. 29.

Figure 9. Following removal of the failing crown, the preparation was refined to remove caries and scanned for crown fabrication.

Figure 10. The virtual crown to be printed on the SprintRay 55 printer and designed in inLab CAD software.

Figure 11. The printed crown made using SprintRay Ceramic Crown resin, following finishing and polishing and ready for intraoral insertion.

The printed crown was tried in for marginal adaption, and integrity was checked with an explorer. A periapical radiograph was taken of the SprintRay Ceramic Crown restoration on the preparation to check the fit, and good marginal adaption was noted (Figure 12, left). The same cementation process was utilized as was performed in case 1. Multi-link Primer A+B was applied to the preparation, with Monobond Etch & Prime applied to the intaglio surface of the SprintRay Ceramic Crown restoration. Multilink dual-cure resin cement was then utilized to lute the crown to the preparation. A periapical radiograph was taken to confirm restoration fit and adaption to the preparation (Figure 12, right). Clinically, the printed crown had good anatomical features and adaptation to the tooth at the margins (Figures 13 and 14). 

Figure 12. Radiograph at try-in of the SprintRay Ceramic Crown printed restoration on No. 29 (left) and following cementation (right).

Figure 13. Final 3D-printed crown using SprintRay Ceramic Crown resin, following cementation, as shown from the occlusal view.

Figure 14. Final 3D-printed crown using SprintRay Ceramic Crown resin, following cementation, as shown from the buccal view.

CONCLUSION

These 2 case examples illustrate crowns printed with SprintRay Ceramic Crown and had a good final polish with marginal adaption similar to ceramic milled/sintered materials. These 2 cases, as well as the other cases in the study, were followed for 6 months or longer, and no noticeable wear was noted on the crown resin or opposing dentition. No fractures were noted in the material in any of the cases, demonstrating that SprintRay Ceramic Crown is a viable material for single crowns and should be considered when planning these types of restorations.

ACKNOWLEDGMENT

The authors wish to thank Henna Lee for the in-office lab work for the 2 cases presented. 

REFERENCES

1. Plotino G, Grande NM, Bedini R, et al. Flexural properties of endodontic posts and human root dentin. Dent Mater. 2007;23(9):1129–35. doi:10.1016/j.dental.2006.06.047 

2. Marending M, Paqué F, Fischer J, et al. Impact of irrigant sequence on mechanical properties of human root dentin. J Endod. 2007;33(11):1325–8. doi:10.1016/j.joen.2007.08.005 

3. Tangsatchatham S, Juntavee N. Flexural strength of various types of computerized machinable ceramic veneered to yttria stabilized tetragonal zirconia polycrystalline ceramic upon different hybridized techniques. Clin Cosmet Investig Dent. 2019;11:61-71. doi:10.2147/CCIDE.S196297 

4. Kontonasaki E, Giasimakopoulos P, Rigos AE. Strength and aging resistance of monolithic zirconia: an update to current knowledge. Jpn Dent Sci Rev. 2020;56(1):1-23. doi:10.1016/j.jdsr.2019.09.002 

5. Aljomard YRM, Altunok EÇ, Kara HB. Enamel wear against monolithic zirconia restorations: A meta-analysis and systematic review of in vitro studies. J Esthet Restor Dent. 2022;34(3):473–89. doi:10.1111/jerd.12823 

6. Gou M, Chen H, Kang J, et al. Antagonist enamel wear of tooth-supported monolithic zirconia posterior crowns in vivo: A systematic review. J Prosthet Dent. 2019;121(4):598-603. doi:10.1016/j.prosdent.2018.06.005

7. Al-Thobity AM, Alsalman A. Flexural properties of three lithium disilicate materials: An in vitro evaluation. Saudi Dent J. 2021;33(7):620–7. doi:10.1016/j.sdentj.2020.07.004 

8. AbuHaimed TS, Alzahrani SJ, Farsi SA, et al. The effect of repeated pressing on the flexural strength, color stability, vickers hardness, and surface topography of heat-pressed lithium disilicate. Materials (Basel). 2022;15(19):6787. doi:10.3390/ma15196787 

9. Jurado CA, Lee D, Cortes D, et al. Fracture resistance of chairside CAD/CAM molar crowns fabricated with different lithium disilicate ceramic materials. Int J Prosthodont. 2022. doi:10.11607/ijp.7802 

10. Kim SH, Choi YS, Kang KH, et al. Effects of thermal and mechanical cycling on the mechanical strength and surface properties of dental CAD-CAM restorative materials. J Prosthet Dent. 2022;128(1):79-88. doi:10.1016/j.prosdent.2020.11.014 

11. Awada A, Nathanson D. Mechanical properties of resin-ceramic CAD/CAM restorative materials. J Prosthet Dent. 2015;114(4):587–93. doi:10.1016/j.prosdent.2015.04.016

12. Barbella M. Dental 3D printing market is expanding 20% annually. Orthopedic Design and Technology. August 12, 2022. 

13. Grzebieluch W, Kowalewski P, Grygier D, et al. Printable and machinable dental restorative composites for CAD/CAM application-comparison of mechanical properties, fractographic, texture and fractal dimension analysis. Materials (Basel). 2021;14(17):4919. doi:10.3390/ma14174919

ABOUT THE AUTHORS

Dr. Jockin practices oral implantology in Tampa, Fla, and serves as adjunct clinical faculty in the department of prosthodontics at the University of Florida College of Dentistry in Gainesville. She is founder of fullarchsuccess.com, director of wellness at Heartland Dental, and lectures nationwide on diverse topics ranging from full-mouth rehabilitation to wellness for the dental team. She can be reached at sjockin@gmail.com.

Disclosure: Dr. Jockin reports no disclosures. 

Dr. Kristallis holds an academic adjunct faculty position in the department of head and neck surgery and plastic surgery at the University of California, San Diego (UC San Diego). He is the founder of San Diego Dental Health Center, LLC, a private practice with the UC San Diego Medical Center that specializes in oral and maxillofacial reconstruction, and a former faculty member at the University of California, Los Angeles School of Dentistry in the department of advanced prosthodontics and maxillofacial prosthodontics. He also maintained a private multispecialty group dental practice in Beverly Hills, Calif. His current focus is on developing integrated clinical digital dentistry protocols as they relate to implant, restorative, and reconstructive dentistry, and he is a Fellow of the Royal College of Dentists of Canada in prosthodontics. Dr. Kristallis is a consultant to numerous dental manufacturing companies regarding biomaterials, dental implants, and CAD/CAM technology. He can be reached at tkristalis@aol.com. 

Disclosure: Dr. Kristallis is a paid consultant for SprintRay. 

Dr. Kurtzman is in private general dental practice in Silver Spring, Md. He is a former assistant clinical professor at the University of Maryland in the department of restorative dentistry and endodontics and a former American Academy of Implant Dentistry Implant MaxiCourse assistant program director at the Howard University College of Dentistry. He has lectured internationally on the topics of restorative dentistry, endodontics, implant surgery, prosthetics, removable and fixed prosthetics, and periodontics and has published more than 800 articles globally as well as several ebooks and textbook chapters. Dr. Kurtzman has been honored to be included in Dentistry Today’s Leaders in CE listings annually since 2006. He can be reached at dr_kurtzman@maryland-implants.com.  

Disclosure: Dr. Kurtzman reports no disclosures. 

Over the past 30 years, the approach to replacing a missing tooth or a couple of missing teeth has changed dramatically. Implant dentistry has almost become the standard of care for single- or multiple-tooth replacement due to the assumption that it is a less invasive and more durable approach than a fixed prosthesis. Traditional crown-supported fixed prostheses require aggressive tooth removal because they need taper and parallelism between both abutments. For many tooth-conserving clinicians and patients, the idea of cutting adjacent teeth for a fixed bridge is unimaginable considering the collateral damage and possible side effects. Most patients deem a fixed implant to be more desirable than a removable partial denture.

After 30 years of dental implants, astute dental professionals have learned that, in many cases, dental implants are neither more minimally invasive nor problem-free. In a large study of the Swedish population, it was found that at 9 years, 45% of all patients presented with peri-implantitis, bleeding on probing/suppuration, and bone loss greater than 0.5 mm, as well as a 7.6% implant loss during the same period.^1,2 

In some cases, the patient has to undergo invasive bone augmentation graft surgeries to place a dental implant. The procedure is far from minimally invasive or problem-free, especially when considering that 11.3% of implants placed on grafted sites fail during the first 5 years of function.³ Also worthy of note is that placing dental implants in young patients may result in long-term “aesthetic failure,” meaning successful integration but unaesthetic positioning due to the development of the alveolar process. When considering the many possible complications of implant tooth replacement and the advances in adhesion and dental materials, it may be time for astute professionals to consider minimally invasive bonded bridges as a first-choice option in certain clinical circumstances. 

THE EVOLUTION OF MINIMALLY INVASIVE ANTERIOR BONDED BRIDGES

When thinking about bonded bridges, many clinicians think of the Maryland bridge,⁴ which is broadly viewed as unsuccessful. A common and very problematic complication with the metal 2-retainer design is the debonding of one retainer, often resulting in secondary caries. This complication can be caused by the lack of sufficient adhesion to the metal pad and the flexibility of thin metal abutment wings, which causes a peeling effect. Also, occlusal forces have consequences on anterior teeth, creating an uneven tooth deflection. All of the above problems combined lead to increased failure rates. Subsequently, Yamashita and Yamami⁵ introduced a new design in Japan, adding mechanical retentive features to the “adhesion bridge” and utilizing a metal adhesive. Figures 1 to 4 show a bonded bridge treated by Dr. Bertolotti, successfully using this concept on a cantilever bridge made more than 30 years ago and still in service. 

Figure 1. Preoperative view of a very young patient with a congenitally missing lateral.

Figure 2. Occlusal view of the retainer wind design, showing the channel preparation on the mesial of the canine.

Figure 3. The cast with the nickel-chromium-based alloy, Rexillium III, for rigidity and a PFM pontic.

Figure 4. The bridge was bonded with Opaque shade PANAVIA 21 (Kuraray Noritake Dental).

THE CANTILEVER BONDED ZIRCONIA BRIDGE

In 1990, all-ceramic adhesion bridges began to be used. Realizing the disadvantages of the 2-retainer design for anterior teeth, Kern⁶ introduced the single-retainer (cantilever) design using all-ceramic materials with excellent success. Alumina bridges had high adhesive success but with higher fracture rates than desirable. Kern subsequently began using zirconia to replace the alumina and established successful methods for bonding to zirconia, a non-etchable ceramic. The survival rates reported were remarkably high: 99.2% at 10 years. Fracture of the zirconia was rare, but “debonds” did occur. Generally, the debonded bridges were successfully rebonded. The rare, fractured zirconia bridges were traced to poor design in the stressed connector areas, and subsequently, minimum design requirements were established for clinical success: a minimum connector height of 3 mm and connector thicknesses of 2 mm, minimum lingual pad thicknesses of 0.7 mm, and a minimum bonding area of 30 mm² on the retainer. Figure 5 depicts an ideal preparation following the above guidelines.⁶ Using the single-retainer zirconia concept, a patient with a missing left lateral incisor received a zirconia bonded bridge with a single canine retainer (Figures 6 to 8). 

Figure 5. Kern-style lingual retained wing preparation. (Image courtesy of Dr. Mathias Kern and Quintessence Publishing.)

Figure 6. Patient with missing lateral. (Image courtesy of Dr. Charles Ruefenacht.)

Figure 7. Lingual view of a zirconia cantilever bridge. (Image courtesy of Dr. Ruefenacht.)

Figure 8. Facial view of the previous case. (Image courtesy of Dr. Ruefenacht.)

ALTERNATIVE DESIGNS FOR ANTERIOR BONDED BRIDGES

Understanding principles learned through the evolution of bonded bridges allows us to be more creative with different designs based on the variety of clinical circumstances our patients present. The 6 primary considerations for success are materials selection, sufficient dimension of connectors, sufficient stiffness on the bonded retainer pad, sufficient size of the bondable surface, proper bonding protocol, and proper management of occlusal forces. An example of a variation required by clinical circumstances would be when a patient is treatment-planned for porcelain veneers for aesthetic reasons and there is a missing tooth. An important variation on the retainer design frequently used by Dr. Ruiz is the porcelain veneer-supported bonded bridge with 2 retainer wings. When the bonded bridge is being placed where severe occlusal forces are expected, a 2-retainer option should be considered. Tagami et al⁷ showed that a 2-retainer option withstands higher debonding forces than a single retainer on posterior bonded zirconia bridges, with narrow- and wide-rest designs showing no statistical difference in retention. Other clinical circumstances possibly requiring 2 retainers could include canine and first premolar replacements, where anterior and posterior teeth are connected, especially on heavy grinders. Figures 9 to 11 depict a case using an anterior veneer to posterior onlay-proximal rest-retainer design.

Figure 9. Canine replacement using an anterior veneer to posterior proximal-facial rest-retainer design.

Figure 10. Wax design of a bonded bridge.

Figure 11. Immediately after bonded cementation.

POSTERIOR MINIMALLY INVASIVE BONDED BRIDGES

While the adhesive forces can retain properly designed cantilevered posterior bridges, Passia et al⁸ have shown short-term clinical durability with cantilever posterior bonded bridges. Long-term experience has shown that posterior teeth with cantilevers often cannot withstand occlusal forces successfully, especially in bruxers; those teeth frequently show signs of occlusal trauma and even fractures (Figures 12 and 13). A posterior 2-retainer design could be considered a safer option because the occlusal forces will be better supported, and with a preparation mostly on enamel, it can still be considered extremely minimally invasive. Design can vary dramatically depending on the condition of existing retainer teeth. One common scenario is the 2-inlay/onlay retainer design, especially when retainer teeth already have existing restorations. Figure 14 shows a molar rest-retainer extending facially for aesthetic purposes. The features in this preparation are sufficient bonding surface to exceed 30 mm² minimum, a 1-mm proximal-occlusal reduction, and needing to maintain parallelism to the second retainer tooth. This preparation is primarily on enamel and margins and always supragingival. The posterior connector size should be 3 mm in height and 4 to 5 mm in width. Figures 15 and 16 show a posterior 2-retainer bonded bridge using the above design. While the profession has limited experience with minimally invasive posterior bonded bridges, they are a very desirable option because of their minimally invasive nature. The authors’ extensive experience in adhesive dentistry gives them the confidence to know that a properly designed and bonded adhesive bridge retainer will have equal or fewer chances of coming loose than a crown-retained counterpart with traditional crown and bridge cement. Attention to lateral forces and understanding the Three Golden Rules of Occlusion⁹ will yield more manageable forces to the fixed prosthesis. 

Figure 12. Before and after photos of a posterior cantilever bridge that caused the full fracture of a retainer tooth.

Figure 13. A second case with a similar clinical circumstance as the previous one.

Figure 14. A molar rest-retainer design.

Figure 15. Zirconia restoration in the cast.

Figure 16. Clinical view immediately after cementation.

ZIRCONIA AND BONDING TO ZIRCONIA

The assumption that all zirconia restorative materials are the same will lead to frustration and failure. Attention should be placed on choosing a properly manufactured, high-strength Y3 (3 mol% yttria) zirconia, like KATANA Zirconia LT, HT, or HTML Plus (Kuraray Noritake Dental). More translucent Y4 (4 mol% yttria) or higher zirconia formulations are weaker and are more likely to lead to fractures of the connector. The elastic modulus of zirconia is superior to precious metal, thus making it a better choice for stiff-bonded retainer pads. Kern et al¹⁰ have shown that 0.7 mm is the sufficient thickness for anterior retainer pads. Posterior rest/pads should be 1 mm. Bonding to zirconia has been tested by long-term studies, allowing clinicians to understand that zirconia adhesion can be very strong and durable.¹⁰ There are multiple ways to successfully bond to zirconia. Blatz et al¹¹ have suggested the APC Concept: A stands for air abrading with aluminum oxide particles; P stands for priming with MDP-based primer (CLEARFIL CERAMIC PRIMER [Kuraray Noritake Dental]); and C stands for cement, using a self-cure or dual-cure resin cement, like Panavia V5. Alternately, Dr. Bertolotti has advocated for more than a decade for a simple and proven method to bond to zirconia: alumina sand blast and air remove the powder, (do not rinse with water, as it slightly decreases adhesion), followed immediately by the application of Panavia F 2.0 or 21 (Kuraray Noritake Dental) (both MDP-containing resin cements do not require primer) and seating on phosphoric-etched enamel.

CONCLUSION 

After almost 40 years of experience with osseointegrated implants for tooth replacement, it is evident that they are not trouble-free nor minimally invasive in many cases. After more than 30 years of trial and experience, adhesion bridges have evolved. They are highly successful treatment options for anterior teeth and, in many cases, should be considered a first-choice treatment over more invasive implant procedures. Their use for posterior missing teeth is now being established with some very promising early results. As always, the clinician is responsible for making a proper case selection, discussing the pros and cons of each procedure, and allowing the patient to make an appropriate, informed decision. Most bridges are currently being made of Y3 zirconia and minimally invasive tooth preparations in enamel.  

REFERENCES

1. Derks J, Schaller D, Håkansson J, et al. Effectiveness of implant therapy analyzed in a Swedish population: prevalence of peri-implantitis. J Dent Res. 2016;95(1):43–9. doi:10.1177/0022034515608832

2. Derks J, Håkansson J, Wennström JL, et al. Effectiveness of implant therapy analyzed in a Swedish population: early and late implant loss. J Dent Res. 2015;94(3 Suppl):44S-51S. doi:10.1177/0022034514563077

3. Eckert SE, Salinas TJ, Akça K. Chapter 6: Implant fractures: etiology, prevention, and treatment. In: Froum SJ, ed. Dental Implant Complications: Etiology, Prevention, and Treatment. 2nd ed. Wiley-Blackwell; 2015: 132–44.  

4. Thompson VP, Del Castillo E, Livaditis GJ. Resin-bonded retainers. Part I: Resin bond to electrolytically etched nonprecious alloys. J Prosthet Dent. 1983;50(6):771–9. doi:10.1016/0022-3913(83)90088-4 

5. Yamashita A, Yamami T. Design and clinical procedures of adhesion bridge (adhesion splint). J Jap Pros Soc. 1982; 26:592–8.

6. Kern M. Resin-Bonded Fixed Dental Prostheses: Minimally invasive – esthetic – reliable. 1st ed. Quintessence Publishing; 2018. 

7. Tagami A, Chaar MS, Zhang W, et al. Retention durability of one-retainer versus two-retainer posterior RBFDPs after chewing simulation. J Mech Behav Biomed Mater. 2022;133:105353. doi:10.1016/j.jmbbm.2022.105353 

8. Passia N, Chaar MS, Kern M. Clinical outcome of posterior cantilever resin-bonded fixed dental prostheses using two different luting agents. J Prosthodont Res. 2022. doi:10.2186/jpr.JPR_D_22_00033 

9. Ruiz JL. The three golden rules of occlusion. Dent Today. 2010;29(10):92–3. 

10. Kern M, Passia N, Sasse M, et al. Ten-year outcome of zirconia ceramic cantilever resin-bonded fixed dental prostheses and the influence of the reasons for missing incisors. J Dent. 2017;65:51–5. doi:10.1016/j.jdent.2017.07.003

11. Blatz MB, Alvarez M, Sawyer K, et al. How to bond zirconia: The APC concept. Compend Contin Educ Dent. 2016;37(9):611–7. 

ABOUT THE AUTHORS

Dr. Ruiz is founder of the Los Angeles Institute of Clinical Dentistry, former course director of the University of Southern California’s Esthetic Dentistry Continuum, associate instructor at Gordon J. Christensen Practical Clinical Courses in Utah, and an independent evaluator for Clinicians Report. He is the author of Supra-Gingival Minimally Invasive Dentistry with Dr. Ray Bertolotti and of many research and clinical articles. He has been named as one of Dentistry Today’s Leaders in CE since 2006. He is also in private practice in the Studio District of Los Angeles. He can be reached at drruiz@drruiz.com.

Disclosure: Dr. Ruiz reports no disclosures.

Dr. Bertolotti received his DDS degree from the University of California, San Francisco, after working as a PhD metallurgical and ceramic engineer at Sandia National Laboratories. He is perhaps best known for introducing “total etch” to North America in 1984. He also introduced Panavia in 1985, tin plating in 1989, self-etching primers in 1992, and HealOzone in 2004. He is the founder of Danville Materials (now part of Zest Dental Solutions) and was director of research at the company. The sectional Contact Matrix System, MicroPrime B, MicroEtcher sandblasting, and intraoral tin plating are also his developments. He is a well-known international lecturer, having presented at invited lectures in more than 30 countries. He can be reached via email at rbertolott@aol.com.

Disclosure: Dr. Bertolotti reports no disclosures.