INTRODUCTION

This article will focus on the ABCs (axis, bite, and chewing) of occlusion and articulation that can be easily implemented to create restorations that require fewer adjustments, saving time and reducing stress. The initial step in reducing positive errors in articulation begins with accurate impressions and bite records, as any error in the technique or material will create a high restoration. All philosophies have the same objective of equal contacts of the occluded teeth with no interferences in all movements. Laboratory technicians can achieve this objective on whatever articulator they may use. Yet most restorations still need adjustments when placed in the patient’s mouth because of inaccurate impressions and/or positive errors in the axis, bite, and chewing of occlusion and articulation.

An articulator is an instrument that represents the temporomandibular joints (axis) or jaws to which study casts may be attached to simulate the static (bite) and dynamic (chewing) relationships between the occlusal surfaces of the teeth during mandibular movements. Positive errors occur when the articulator undercompensates for mandibular movements, resulting in a positive feature on the occlusal surface where that feature should be smaller or nonexistent.¹ Negative errors occur when the articulator overcompensates for mandibular movements, resulting in a negative feature on the occlusal surface, which allows the teeth to disclude more freely.¹ Positive errors can create interferences that may need to be adjusted in the axis (opening and closing movements), the bite, and chewing (envelope of function movements) depending on the discluding factor of the protrusive pathway, influence of the Bennett movement, and steepness of the anterior guidance.

AXIS

It is important to relate the teeth to the patient’s axis to be able to simulate more accurate opening and closing movements in an articulator. The most common error in relating study models is using a simple hinge articulator without the use of a face-bow. The axis in simple hinge articulators (Figure 1, red point B) is always located below the patient’s axis (Figure 1, green point A). Therefore, simple hinge articulators produce more vertical opening and closing axis movements (Figure 1, red pathway b) than the patient’s opening and closing axis movements (Figure 1, green pathway a). This positive error in articulator axis movements can create interferences in the mesial inclines of the upper teeth and/or distal inclines of the lower teeth that will require adjustments.² It is much better to have the articulator axis closer or a little above the patient’s axis to reduce positive errors for fewer adjustments of opening and closing movements of the axis.

Figure 1. Axis of rotation discrepancies.

Research shows that a face-bow has a statistical average to the axis by referencing the patient’s ears, which relates the study models much closer to the patient’s axis to reduce positive errors.³ The Kois Dento-Facial Analyzer (DFA) is a simple instrument that incorporates a 3D guide plane to reference how the occlusal plane relates to the face for aesthetics, as well as having a functional relationship of the teeth to the axis based on an average axis-incisal distance of 100 mm (Figure 2).⁴ This 100-mm-average axis-incisal distance is supported by Monson’s Spherical Theory (4 in = 101.6 mm)⁵ and Bonwill’s Equilateral Triangle,⁶ as well as other research showing the Kois DFA to be as functionally accurate as a face-bow.^7,8 The average 100-mm axis-incisal distance is engineered into the Kois Platform on the articulator, which can mount study models with or without the use of the Kois DFA (Figure 3).⁴ This standard functional mounting without a face-bow seems to place the articulator axis above the patient’s axis to create a negative error in opening and closing movements of the axis.

Figure 2. Measuring axis-incisal distance.

Figure 3. Average axis-incisal distance.

The steps are as follows: 

Step 1. Assemble the Kois DFA and add bite registration material to the Kois Index Tray. Insert the Kois DFA into the patient’s mouth and place the vertical wall on the Kois Index Tray to the facial of the central incisors (Figure 4). This will register and transfer the central incisal edge of the 100-mm axis-incisal distance for function.

Step 2. Align the vertical rod to the patient’s facial midline and level the lateral wings (Figure 5). Keeping the vertical rod and lateral wings aligned, push up lightly until a tooth touches the tray and then hold until the material sets. This will register and transfer any cant of the occlusal plane related to the horizon and facial midline for aesthetics.

Step 3. Index the Kois Index Tray to the Kois Adjustable Platform on the articulator and orient the upper study model into the impression on a horizontal Kois Index Tray. The incisal edge is now 100 mm from the axis of the articulator for function (Figure 6). Mount the study models to the articulator in the usual manner.

Optional. For a standard functional mounting without a face-bow, simply place the upper study model on the Kois Platform with the incisal edge to the 100-mm line on the waxing guide (Figure 7) (PAL 2.0 shown). 

The Panadent PAL 2.0 Articulator System with an integrated Kois Platform has the same anatomical axis as the full-size articulator and is designed for general and digital dentistry (Figure 8).

Figure 4. Kois Dento-Facial Analyzer (DFA) profile.

Figure 5. Kois DFA frontal view.

Figure 6. Kois DFA maxillary mounting.

Figure 7. Standard functional mounting.

Figure 8. Three-dimensionally printed mounted models.

BITE

All dentists use marking ribbons to mark and adjust any high spots to achieve equal contacts of the teeth when the patient bites (maximum intercuspation). It makes anatomical sense to have the jaw in a physiologic position with the condyles against the disc orthopedically aligned and centered in the fossa when all teeth are occluded with normal neuromuscular function (Figure 9).

Figure 9. Equal contacts of teeth.

Since the articulator axis is not the true hinge axis of the patient when using a face-bow or Kois DFA, changing vertical dimension of occlusion (VDO) on the articulator can create positive errors or discrepancies in the bite (Figure 10).³ If changing VDO, it is recommended to take an interocclusal record at the VDO from which the restorations, prostheses, or occlusal splint will be fabricated. This will reduce positive errors for fewer adjustments of the bite.

Figure 10. Face-bow research.

CHEWING

It is important to understand incising and lateral chewing movements (envelope of function) to simulate more accurate chewing movements in an articulator. The protrusive pathway (downward and forward movement of the condyles), together with incisal guidance, can have a discluding influence on the distal inclines of the upper teeth and/or mesial inclines of the lower teeth in incising chewing movements (Figure 11). Research shows that the angle of the protrusive pathway ranges from 20° to 75° to an axis-horizontal plane of reference. The protrusive pathway is the only discluding factor that can be programmed into an articulator that can be communicated with a protrusive interocclusal record to set the articulator. If no protrusive record is taken, it is recommended to set the articulator to a 20° protrusive pathway to reduce positive errors in incising movements of chewing.

Figure 11. Effect of protrusive pathway.

The Bennett movement (inward movement of the condyles), together with canine guidance, can have a discluding influence on the buccal and lingual cusps of the posterior teeth in lateral chewing movements (Figure 12). Research shows that Bennett movement ranges from 0.5 to 2.5 mm with approximately 90% of the population having 1.5 mm of Bennett movement or less.⁹ It is recommended to set the articulator to at least 1.5 mm of Bennett movement to reduce positive errors for fewer adjustments in lateral movements of chewing.

Figure 12. Effect of Bennett movement.

Most semi-adjustable articulators incorporate a straight-line, undercompensated Bennett guide (Figure 13, graph a), meaning the patient can move (curved dotted line) beyond the articulator guide (solid line), which may create positive errors in lateral chewing movements. The “Immediate Side Shift” articulator incorporates an overcompensated Bennett guide (Figure 13, graph b), meaning the articulator can move (solid “S” lines) beyond the patient’s movements (curved dotted line), which may create negative errors, but may also produce flatter anatomy. The Panadent articulator incorporates a curved-path, compensated Bennett guide (Figure 13, graph c), meaning the articulator moves more like the patient’s jaw movements, which may reduce positive errors for fewer adjustments in lateral movements of chewing.^10,11

Figure 13. Types of articulator guides.

IN SUMMARY

Using the Kois DFA or doing a standard functional mounting to relate the teeth to an average anatomical axis may reduce positive errors for fewer adjustments in opening and closing movements of the axis.

Taking an interocclusal record at the VDO desired may reduce positive errors for fewer adjustments of the bite. 

Setting the articulator with a 1.5-mm Bennett movement and a 20° protrusive pathway may reduce positive errors for fewer adjustments of incising and lateral movements of chewing.

REFERENCES

1. The glossary of prosthodontic terms: ninth edition. J Prosthet Dent. 2017;117(5S):e1-e105. doi:10.1016/j.prosdent.2016.12.001 

2. Weinberg L.A. An Evaluation of Basic Articulators and their Concepts Part II. Arbitrary, Positional, Semiadjustable Articulators. In: J Prosthet Dent. 1963;13(4):645-663. doi:10.1016/0022-3913(63)90134-3

3. Teteruck WR, Lundeen HC. The accuracy of an ear face-bow. J Prosthet Dent. 1966;16(6):1039–46. doi:10.1016/0022-3913(66)90169-7 

4. Kois JC, Kois DE, Chaiyabutr Y. Occlusal errors generated at the maxillary incisal edge position related to discrepancies in the arbitrary horizontal axis location and to the thickness of the interocclusal record. J Prosthet Dent. 2013;110(5):414–9. doi:10.1016/j.prosdent.2013.06.005 

5. Monson GS. Applied mechanics to the theory of mandibular movements. Dental Cosmos. 1932;74:1039–53. 

6. Bonwill WG. The scientific articulation of the human teeth as founded on geometrical, mathematical, and mechanical laws. D Item Interest. 1899;21:617–36; 873–80.

7. Lux LH, Thompson GA, Waliszewski KJ, et al. Comparison of the Kois Dento-Facial Analyzer System with an earbow for mounting a maxillary cast. J Prosthet Dent. 2015;114(3):432–9. doi:10.1016/j.prosdent.2015.02.022

8. Thompson GA, Nick C, Francisco P, et al. Comparison of two arbitrary cast transfer systems with a kinematic facebow for mounting a maxillary cast on a semiadjustable articulator. J Prosthet Dent. 2021;S0022-3913(21)00002-0. doi:10.1016/j.prosdent.2020.12.023

9. Lundeen HC, Gibbs CH. Chapter 1: Jaw movements and forces during chewing and swallowing and their clinical significance, In: Advances in Occlusion. John Wright Publishing; 1982:2-32.

10. Lee RL. Jaw movements engraved in solid plastic for articular controls. I. Recording apparatus. J Prosthet Dent. 1969;22(2):209–24. doi:10.1016/0022-3913(69)90248-0 

11. Lee RL. Jaw movements engraved in solid plastic for articulator controls. II. Transfer apparatus. J Prosthet Dent. 1969;22(5):513-27. doi:10.1016/0022-3913(69)90227-3

ABOUT THE AUTHOR

Mr. Lee is president and owner of Panadent Corp. He is the son of Dr. Robert Lee, who published his research in the Journal of Prosthetic Dentistry in 1969, which led to the development of the Panadent Articulator System. He holds several patents for face-bow and articulator designs. Mr. Lee has published several articles and has lectured nationally and internationally with his extensive knowledge in articulator design and its relationship to occlusion and aesthetics. He can be reached at tlee@panadent.com

Disclosure: Mr. Lee is president and owner of Panadent Corp.

“Conservative” and “Necessary”: A “Marriage of Philosophies”

It has been stated by Shavell that “occlusion and morphology are the common denominators of all dentistry.”¹ A single tooth or restoration can have a profound effect on the function and comfort of a patient if it is not properly integrated into the patient’s natural occlusal function.

It is unfortunate that “modern” dentistry has such a “conformative” approach under the guise of being “conservative” or committing “over-treatment.” With the “tooth-at-a-time” or “if it’s not broke, don’t fix it” approach, are we really doing our best to help patients keep their teeth for the rest of their lives?

How many teeth, as Dr. Harold M. Shavell would say, “have been sacrificed on the altar of false conservatism?” These are questions we all wrestle with every day in private practice. One thing that is important to remember is that the muscles always win!

Without proper integration into a non-interfering occlusal scheme, the best restorative effort will ultimately fail, regardless of the material used.

The following is a case report that illustrates these premises while addressing the replacement of a single-tooth restorative failure.^2,3

A CLASS IV COMPOSITE FAILURE: CASE HISTORY AND RESTORATIVE PLAN

The patient in Figure 1 presented with a broken Class IV mesial incisal composite restoration on tooth No. 8. It had been replaced 3 times during the past year and had broken again. Aside from the amount of composite on the facial surface that extended beyond the fractured area, a majority of the lingual (palatal) surface of the tooth was worn through to the dentin due to hyperfunction in protrusive and lateral excursions for many years, creating a functional and an aesthetic dilemma for this patient.

A “conservative” approach may have been to simply bond the tooth again with composite and hope for the best. However, when considering the functional stress in this area, even with the best tooth alignment, this may not have been the best long-term approach. After all, how “conservative” is it to continually “assault” the tooth with rotary instrumentation to keep “fixing” a composite that continues to break? What about the alignment of the opposing teeth?

It can be seen in Figure 2 that excessive incisal wear was present on the incisal edges of teeth Nos. 24 and 25. From the incisal view (Figure 3), extensive wear is seen on all mandibular anterior incisal edges as a result of occlusion (occlusal disease) that is often seen yet left untreated.

Tooth No. 25 was also facially positioned so that, in protrusive excursions, it engaged the palatal surface of tooth No. 8, prematurely placing additional stress on both the palatal surface and incisal edge of tooth No. 8 before coupling with the remainder of the maxillary anterior segment.

So, to address these issues restoratively, it involved more than just fixing a chipped composite restoration. Orthodontics to correct tooth alignment was discussed with the patient, but there was no interest. That being said, a “Plan B” could have been to restore tooth No. 25 in such a way that the position of the tooth facially and the incisal edge would not engage the palatal surface of tooth No. 8 prematurely, followed by restoring the palatal surface and incisal facial fractured area with ceramic to replace the lost enamel and reinforce what remained.

The decision was made to restore tooth No. 8 with a ceramic restoration and tooth No. 25 with a direct composite. Aesthetically, for tooth No. 8, an aesthetic match to tooth No. 9 could have been better achieved with layered ceramic.

Composite resin was chosen as a more conservative and less costly option for tooth No. 25, but the patient was told that it may require a ceramic restoration at a later time.

Operative Procedure No. 1: Tooth No. 25 Direct Composite Veneer

A preoperative shade was chosen and photographed (Figure 4) for the ceramist using a digital camera with a function that isolates the tooth shade from the rest of the oral cavity (EyeSpecial [Shofu Dental]). Next, the facial surface of tooth No. 25 was prepared orthodontically to move the facial surface and incisal edge lingually (Figure 5). It is important to note that the beveled facial surface of tooth No. 25 after preparation had a knife-edge cervical margin that was about 2 mm supragingival.

This “long bevel” allowed for a more aesthetic blend of composite and tooth structure while leaving the emergence profile of the natural tooth untouched. Figure 6 shows the positioning of a Uveneer template system (Ultradent Products), which was used to fabricate the facial and incisal anatomy in composite and “move” the tooth (tip) in the lingual direction. Prior to the placement of composite, the tooth (enamel) surface was etched with phosphoric etch (Ultra-Etch [Ultradent Products]) for 15 seconds, thoroughly rinsed, and then air dried.

A universal bonding resin (Peak Universal Bond [Ultradent Products]) was applied to the tooth surface; air-thinned, evaporating the solvent; and then light cured for 20 seconds (VALO Grand [Ultradent Products]). Figure 7 shows the initial increment of composite used to build up the incisal one third of the tooth to its new “lingualized position.”

The Uveneer template system was then filled with the chosen shade of composite (Mosaic Universal Composite [Ultradent Products]) and placed on the facial surface of the tooth in the proper alignment with the adjacent teeth and light cured. Figure 8 shows tooth No. 25 after removal of the Uveneer template and some minor incisal adjustments and polishing.

Operative Procedure No. 2: Tooth No. 8 All-Ceramic Restoration

Tooth No. 8 was prepared for an all-ceramic crown. It is important to stress that the preparation of the palatal surface is critical. It must be prepared to 1.0 to 1.5 mm of reduction following the curvature of the unprepared palatal surface (maxillary palatal concavity).

This is so the restoration can follow the natural palatal curvature at the appropriate thickness of restorative material for strength. Remember, the maxillary palatal concavity is determined by the angle of the eminence and the envelope of function, both occlusal determinants that must be followed when restoring maxillary anterior teeth (Figures 9 and 10).

Once the preparation is completed (Figure 11), the master impression can be made. 

The “2-Cord” Technique for Indirect Impression Making

A 2-cord impression technique is an extremely predictable way to capture quality master impressions for full coverage (circumcoronal) and partial coverage restorations with either intracrevicular or equicrevicular margins (at the free gingival margin).⁴ First, a #00 retraction cord (Ultrapak [Ultradent Products]) is placed at the base of the gingival sulcus around each preparation, starting from the lingual aspect, around the proximal to the facial aspect, then back through the opposite proximal area to the lingual starting point.

The excess at both lingual ends is trimmed, and the opposing ends of the cord are tucked into the lingual gingival sulcus so that they butt against one another (not overlapping). Once the first retraction cord is properly placed, and prior to placement of the second retraction cord, any minor marginal correction can be done to the preparation using a course or fine diamond instrument of the appropriate diameter. Next, a #1 cord (Ultrapak) is placed on top of the #00 in the same manner as previously described.

If desired, all cords may be soaked in a hemostatic solution (ViscoStat Clear [Ultradent Products]), and then the excess is removed with a 2 × 2 in gauze sponge prior to placement. Next, using a cotton pledget, the preparation is wiped with Consepsis (Ultradent Products) to make sure the surface is clean and free of “prep debris” from the diamond instrument.

When ready (usually after all cords are in place and the fit of the impression tray has been verified), the #1 cord is partially pulled out of the sulcus using an explorer on the facial aspect of each preparation, and the amount of retraction (and lack of moisture or blood contamination) is evaluated. Remember, the master impression must capture not only the entire restorative margin, but also 0.5 mm of the tooth/root surface apical to the margin.

If the marginal gingiva adjacent to any restorative margin rebounds to contact the tooth/margin after the top cord is pulled, a small piece of a larger diameter cord (#2) (Ultrapak) is placed into the affected area for an additional minute and then removed. This added retraction should be sufficient to create a space between the tooth surface and the inner dimension of the gingival sulcus. The goal of retraction is to “create a moat (a space in which to inject light-bodied impression material) around the castle (tooth preparation).”  

A Super Pulsed Diode Laser as an Adjunct to Cord Packing

If any portion of the circumferential gingival tissue is not sufficiently retracted away from the emergence profile of the tooth/preparation after placement of the #1 retraction cord, a diode laser can be used to perform a minor gingivoplasty on the overlapping gingival tissue above the top cord so that it is visible prior to its removal. This is common in interproximal areas where the gingival tissues (papilla) may be slightly enlarged.

It is not recommended to hope that the heavy-bodied tray material will “push” the tissue out of the way to let the light-body material access the gingival crevice. Figures 12 and 13 show the super pulsed diode laser (Gemini [Ultradent Products]) performing a gingivoplasty above the top cord with the retraction cord entirely visible prior to its removal and injection of the light-body impression material. When the cord is removed, an impression of the margin and 0.5 mm of tooth/root surface apical to the margin is virtually assured.

To capture a precise master impression, light-bodied impression material should be injected not only around the prepared teeth but also over all occlusal and incisal surfaces so that the stone models can be accurately articulated. After injection of the light-bodied material, the impression tray with the heavy-bodied impression material is placed in the mouth for the appropriate time, based on the manufacturer’s recommendations. 

Delivery of the All-Ceramic Restoration

Figure 14 shows a retracted smile view of the provisional restoration and gingival tissues around tooth No. 8 prior to delivery of the definitive restoration.

After removal of the provisional restoration and any remaining provisional cement, the restoration was tried in, and the proximal contacts and occlusion were adjusted and then polished as necessary. Next, the preparation was disinfected with Consepsis. Also, the restoration had been etched by the laboratory, so the etched surface was treated with a silane coupler prior to cementation as per the manufacturer’s instructions.

The restoration was then luted using a dual-cured resin cement (PermaFlo DC Translucent [Ultradent Products]).

Figures 15 and 16 show the restoration of tooth No. 8 with an all-ceramic crown after cementation. 

CONCLUSION

It is important to always consider that the restoration of a single tooth can affect the occlusion in a profound way. The reverse is also true: Not considering the occlusion can affect a single restoration both in contour and longevity. It is always recommended to consider these issues prior to any restorative endeavor (Figures 17 and 18).

REFERENCES

1. Shavell HM. Occlusion: lost art, lost discipline: Part 1. Journal of the Pakistan Dental Association. 2013;22:164-177.

2. Parker MW. The significance of occlusion in restorative dentistry. Dent Clin North Am. 1993;37:341-351.

3. Neff P. Trauma from occlusion. Restorative concerns. Dent Clin North Am. 1995;39:335-354. 

4. Cloyd S, Puri S. Using the double-cord packing technique of tissue retraction for making crown impressions. Dent Today. 1999;18:54-59.

ABOUT THE AUTHOR

Dr. Lowe received his DDS degree from the Loyola University School of Dentistry in 1982. He is an assistant professor in the Department of Oral Rehabilitation Division of Restorative Dentistry at the James B. Edwards College of Dental Medicine at the Medical University of South Carolina. He previously taught at the Loyola University School of Dentistry while building a private practice in Chicago. Dr. Lowe currently maintains a practice in Charlotte, NC. He can be reached at boblowedds@aol.com.

Disclosure: Dr. Lowe received an honorarium from Ultradent Products. 

INTRODUCTION
Bruxism is one of the most common dental diseases, with one in every 3 patients coming into the office having some form of bruxism.¹ Even though bruxism is so common, it is still one of the least understood dental problems. Certainly every dentist knows that bruxism is co-morbid with temporomandibular disorders (TMD), orofacial pain in the head and neck, certain headaches, and migraines. To be honest, many dental professionals just take it for granted, to the point where a treatment plan is not very thought through, beyond making the patient a “bruxism” appliance, that is.

What kind of bruxism appliance do you make in your practice? Most dentists have a favorite regardless of the intensity of the patient’s bruxism or the TMD/orofacial pain with which the patient presents. Some of you like an appliance that is an anterior bite plane, others like full-arch coverage, and some only use posterior coverage. An American Academy of Facial Esthetics (AAFE) study in September 2013 of 946 dental professionals found that most only use one type of bruxism appliance 95% of the time, regardless of the patient’s problem. Also, according to the same study, 86% of these same dentists say that the bruxism appliance does not resolve the patient’s conditions satisfactorily. Another reason that bruxism therapy has been so frustrating in the past is that there was no way to objectively measure a patient’s bruxism by monitoring the number of bruxism and clenching episodes per sleep hour.

In listening to feedback from many lecture attendees each year, I’ve found that clinicians routinely report that bruxism appliance therapy is one of the most challenging and frustrating treatments they deliver to patients. The scenario typically is this: patients present with some kind of facial pain; we tell them the pain is coming from bruxism, which happens while they sleep; we deliver an appliance and tell them to wear this for one to 3 months; and then we simply wait and see what happens. Most of the time, the patient gets worse, we adjust the appliance, and then we keep adjusting it until either we give up or the patient gives up and, worse yet, does not come back. How many times has that scenario happened to you? Let’s take a step back and examine this more closely from a few angles.

Obstructive Sleep Apnea and Bruxism: Are These Related?
First, let’s take a look at one of the possible causes of bruxism, and it will surprise many of you reading this article.

Dental sleep medicine is a fast growing area of dentistry. There are approximately 40 million people in the United States with obstructive sleep apnea (OSA), with 90% of those undiagnosed. Simply put, OSA is a medical condition in which there is a physical obstruction (tongue, pharyngeal muscles, epiglottis, vocal cords, as examples) that blocks the airway which then stops the patient from breathing during sleep. An apnea is an event where the patient stops breathing for a minimum of 10 seconds during sleep. A hypopnea is an event where the patient has significantly reduced airflow because of a partially blocked airway for at least 10 seconds while sleeping. Patients with OSA will have multiple apneas/hypopneas every night while they sleep, with the potential to severely impact their health. OSA is co-morbid, dramatically increasing the incidence and severity of diabetes, hypertension, stroke, and heart attacks in patients. (Let’s not forget that dentists are patients too, by the way.)

Okay, so we agree that OSA is a very significant health problem; why should the dental profession care? One reason is that we certainly care about our patients, and we should be screening for OSA with simple self-tests as part of a patient’s medical history. The other reason is that moderate to severe bruxism is co-morbid with OSA. What is the connection? The brain’s mechanism to get the patient to breathe when he or she has a blocked airway causing an apnea is as follows: The brain needs to open the airway and gets the muscles of mastication to start working hard and fast, a process we know as bruxism. The masticatory muscles move the jaw forward, the airway opens, and the patient takes in a deep rescue breath. Then, patient falls back asleep, the airway gets blocked again, and the process repeats itself over and over many times during the night. This is known in evidence-based studies as sleep bruxism.^2,3

This same patient wakes up in the morning, the jaws hurt, the facial muscles hurt, and the patient has headaches. The individual then comes to your office because he or she has TMD, and it is clear from an examination that the patient is bruxing. If you don’t have any knowledge about OSA, or whether the exact origin of the pain is in the TM joint (TMJ) or the head and neck muscles, how would you know what kind of appliance to make? Let’s say your patient has OSA and you choose your favorite bruxism appliance, which may position the mandible posteriorly; you will hopefully realize that this “bruxism” appliance will close the patient’s airway further at night, making the OSA worse and most likely resulting in an increase in bruxism activity. Additionally, if the patient’s orofacial pain is coming from either the TMJ and/or muscle trigger points and you make the wrong kind of appliance, the pain will get worse, not better.

This is why I and the AAFE faculty all teach that there is no such thing as just making a “bruxism” appliance for patients. You need to consider all of these questions before you put an appliance in your patient’s mouth:

• Does the patient have sleep apnea?
• Does the patient have orofacial pain caused by muscles?
• Does the patient have orofacial pain originating in the TMJ?
• Does the patient have prior restorations, such as implants, veneers, crowns, bridges, and/or large restorations? (Note: This will determine appliance design.)
• Does the patient only have bruxism? If only protection of the dentition is needed with no other conditions, use the appliance of your choice.

In the past, many dentists have invested in a sleep monitor that only measures for OSA. Because OSA is a medical condition, which requires a diagnosis by a physician, and the dentist could not directly relay any kind of data regarding bruxism, these cases were handed over to the physician, who might not have been knowledgeable about dental sleep medicine or bruxism. Dentists also did not receive any information about the patient’s bruxism from these monitoring units.

New Technology
There has been an exciting advancement in the areas of bruxism and dental sleep medicine that will now let a dental clinician objectively collect data to measure bruxism and OSA in patients. The STATDDS Bruxism and Sleep Monitor (STATDDS) (Figure 1) is a very cost-effective home test device that the patient wears at night while sleeping. The exclusive software that comes with this monitor, made specifically for dentistry, analyzes the testing data and gives the dentist a simple-to-understand report with the patient’s bruxism episodes index (BEI) and the apnea/hypopnea index (AHI). The BEI measures the number of bruxism episodes per sleep hour and the AHI measures how many apnea/hypopneas per sleep hour. The monitor can be purchased, or it can also be rented by the dental practice. It is affordable, as each home test costs less than $20 to administer. Currently, this is the only monitor of its kind with specialized software that has been specifically configured to analyze both the BEI and AHI, and with the ability to produce patient specific reports for dental offices.

I use the rule of 5 when looking at these numbers: If the BEI is greater than 5, the patient has clinically significant and destructive bruxism that needs to be addressed not only with an appliance, but also in my choice of dental materials if any restorative dentistry is needed (such as crowns, bridges, implants, etc). If the AHI is higher than 5 and less than 30, then a mandibular advancement appliance for obstructive sleep apnea is now considered primary therapy. (Note: Remember that OSA is a medical condition that requires a diagnosis by a physician.) I can now show a physician that the patient has bruxism, for which I am the primary provider as a dentist and, if the sleep apnea is diagnosed as mild to moderate, I can take care of both conditions with the right appliance.

MINI CASE REPORTS
Here are some examples of how objective evidence and criteria now can help with my diagnosis and treatment plan.

Case 1
Figure 2 shows a report generated with the STATDDS monitor. This patient had a BEI of 7.2 per hour and an AHI of 7.4. This patient has severe bruxism and numbers that indicated mild OSA. A treatment plan was created with the patient’s physician. An AAFE Class I transitional appliance, such as a Silent Nite (Glidewell Laboratories) (Figure 3), was made for the patient to see if he could tolerate mandibular advancement to open his airway. This appliance eliminated his snoring, which was a good indication that further appliance therapy would most likely be effective. At this point, an AAFE Class IV mandibular repositioning appliance that has been FDA approved for OSA (such as a Narval CC [Great Lakes Orthodontics]) (Figure 4) was made for the patient. The patient was then retested with the STATDDS home test monitor while wearing the appliance and one can see the improvement in Figure 5; the patient’s BEI was much improved (at 0.4 per hour) and the AHI dropped to 1.1. We now have objective data showing the success of the mandibular repositioning appliance, resulting in the elimination of the patient’s bruxism and OSA. The patient’s physician was pleased, and the patient was very happy. Furthermore, as the treating dentist, I was assured that his dental implant therapy would last a long time because it would not be subjected to severe bruxism forces.

Case 2
Thousands of dental professionals are now using Botox for relief of bruxism and orofacial pain. With the STATDDS monitor, we can now quantify the successful results as well as manage the dosage needed, depending on the test results. This patient is a good example of the demonstrable success that we can now measure with objective evidence.

Figure 6 shows the pre-op photo of a patient who came into the office with a 10-year history of orofacial pain. Her test results (Figure 7) showed a BEI of 5.2 and an AHI of 4.8. After trigger point injections with approximately 60 units of Botox, her postoperative test and the results were impressive (Figure 8). The patient’s BEI fell to 0.6. Interestingly, the patient’s AHI also dropped significantly. (Both the BEI and AHI results in patients are a development currently being studied by the AAFE in a multilocation study.) Figure 9 shows the patient’s aesthetic results after therapeutic injections with Botox as well as the elimination of her orofacial pain for the first time in 10 years. Cases like this clearly demonstrate to both the patient and the clinician how successful Botox therapy can be in the treatment of bruxism and orofacial pain. I use Botox routinely in most of my restorative cases to control the masticatory muscles to achieve long-term success for the dentistry I place in patients’ mouths. With the ability to now obtain objective and reliable data, I can now quantify and titrate my Botox dosages for maximum effectiveness.

Figure 9. Botox injections improved the patient’s aesthetics and also eliminated her orofacial pain.

TRAINING IS REQUIRED
Training is essential in the areas of orofacial pain, dental and facial aesthetics, dental sleep medicine, and oral appliances for bruxism therapy before a dentist ever makes another “bruxism” appliance again. Many bruxism appliances that are currently being made may negatively impact a patient’s health if you do not understand the impact these appliances have on the TMJ, orofacial pain, and OSA. Successful restorative, bruxism, and orofacial pain treatment has now entered a new era with the use of cost effective qualitative testing, Botox, and the relationship of oral appliances and OSA. (When documented and billed properly, dentists can also often be paid by the patient’s medical insurance for many of these services.) It is time for dentistry to catch up with medicine in the ability to objectively measure and use data to help us diagnose and more effectively treatment plan our patients for the best therapeutic pain and restorative outcomes.

References

1. Academy of General Dentistry. AGD: FACTSHEET. What Exactly Is Bruxism? Available at: cfdds.com/images/pdfs/bruxism.pdf. Accessed on July 24, 2014.
2. Lavigne GJ1, Rompré PH, Montplaisir JY. Sleep bruxism: validity of clinical research diagnostic criteria in a controlled polysomnographic study. J Dent Res. 1996;75:546-552.
3. Khoury S, Rouleau GA, Rompré PH, et al. A significant increase in breathing amplitude precedes sleep bruxism. Chest. 2008;134(2):332-337. [Epub May 19, 2008]

Further Reading and Learning Resources
The Web site facialesthetics.org offers information about live-patient frontline TMJ/orofacial pain training, frontline dental sleep medicine, bruxism therapy and medical insurance, and Botox and dermal fillers training. You can also download Dr. Malcmacher’s resource list and sign up for a free monthly e-newsletter at the site.

Dr. Malcmacher is a practicing general dentist and an internationally known lecturer and author. He is president of the American Academy of Facial Esthetics. He also has been awarded his Mastership in the AGD. He can be reached at (800) 952-0521 or via e-mail at the address drlouis@facialesthetics.org.

Disclosure: Dr. Malcmacher is president of the American Academy of Facial Esthetics and is a consultant for STATDDS.

Figure 1. Preoperative view of patient presenting with moderate to severe temporomandibular dysfunction (TMD) pain.

Figure 2. Bleeding the catalyst and base before attaching the mixing tip.

Figure 3. Dispensing the alginate substitute (Silginat [Kettenbach LP]) into the impression tray.

Figure 4. Seating the filled impression tray.

INTRODUCTION
The options for treatment of patients experiencing pain associated with temporomandibular dysfunction (TMD) have dramatically increased over the past decade. Regardless of the treatment philosophy utilized, most begin with a removable mandibular positioning device or orthotic to begin therapy. The rationale behind the use of a removable orthotic is based in the concept of alleviating the patient’s pain, stabilizing painful muscles and joints, and to begin establishing a physiological arc of closure, vertical dimension, and occlusal scheme prior to moving on to more definitive, possibly invasive, treatment.
The role of accurate full-arch impressions and a proper bite registration (at the desired treatment position) is tantamount. Inaccurate preliminary casts created from impressions that exhibit voids, pulls, or drags, or from distorted impressions made from materials that exhibit poor tear strength, elastic deformation, and dimensional instability, must be rejected. So, every inaccuracy allowed to slip by with the preliminary models and bite registration can parlay into errors that will hinder reaching any definitive treatment goals.

Bite Registration Materials
A bite registration material must be able to accurately reproduce the exact intermaxillary relationship. Inaccuracies during bite registration can lead to incorrect contouring of the occlusal surfaces by the dental laboratory team, resulting in many time-consuming adjustments of the restoration by the dentist.
A bite registration material should be able to be easily dispensed onto the occlusal surfaces of the teeth, having enough flow to encompass the occlusal one third of each tooth; however, all bite registration materials must be fluid enough to not deflect or impede the path of closure into the desired occlusal position. Ideal bite registration materials should also have sufficient flexibility to be removed from the mouth without permanent elastic deformation, yet polymerize to a final hardness that permits easy trimming of any excess material. Materials used for bite registrations taken in the patient’s existing centric occlusion (maximum intercuspation) typically require the least amount of working time in that no mandibular manipulation, or other form of jaw positioning, is required prior to material polymerization. When alterations to the patient’s occlusal relationship are being made, the ideal working time is dependent on the time required to reach the precise mandibular position.
There are many bite registration materials available to clinicians today (ie, wax, cold-cure acrylics, bis-acrylics, and addition-curing silicones). The latest bite registration material is the addition-curing silicones (A-silicones). These materials are vinyl polysiloxane (VPS) impression materials that have been chemically altered to make them ideal for use as bite registration materials. All A-silicones are dispensed from a dual-barreled cartridge via a spiral tip, assuring proper mix ratios of catalyst and base. Depending on the brand, A-silicones vary in wetability, flexibility, brittleness (during removal from undercuts as well as during trimming), consistency and handling, and length of working time from mix to set. Some dental manufacturers offer a choice of working times within the same brand so that clinicians can avoid stocking different brands for the variety of clinical situations common to most dental offices.

Preliminary Impression Materials
Historically, there have been many commercially available materials that can be used for preliminary impressions for diagnostic casts and study models (ie, alginate [reversible hydrocolloid], polyether, and VPS).
Ideally, materials designed for taking preliminary impressions must be highly accurate, easy to dispense at precise catalyst/ base ratios, and be sufficiently elastomeric to be removed from the mouth without deformation. They should also have sufficient tear strength to endure being pulled from interproximal embrasures and beneath fixed-bridge pontics. Since is it quite common in TMD therapy for preoperative models to be sent directly to dental laboratories, they must be able to be disinfected and durable enough to be poured multiple times, remaining accurate and available for repouring during the course of treatment. Full-arch impressions need enough working time to fill a full-arch tray and be seated in the mouth, yet not require uncomfortably long set times while in the mouth. Lastly, since impression materials typically used for preliminary models are also used to make impressions for many other clinical procedures, the ideal impression material should be affordable.
Traditionally, many dentists were taught to use alginates for preliminary impressions. Many dentists simply find the “feel” of alginate to be ideal for full-arch preliminary impressions; however, despite these attractive advantages, the physical properties and working characteristics are extremely technique sensitive. Exact powder/water ratios are easily abused and erratic mixing can lead to errors in flow, air entrapment, dimensional stability, and tear strength in the mouth. Because alginate materials are water-based, they are highly subject to evaporation over time and must be poured immediately to be accurate. Further frustration can come from not removing the stone casts from the alginate while they are still hydrated, which may result in model fracture, and repours are not possible.
Some dentists choose to use modern polyether and VPS materials when making preliminary impressions. These materials require no hand mixing, are easily dispensed and are quite capable of creating highly accurate, elastomerically-stable impressions that can be disinfected and sent to the dental laboratory and poured multiple times. They are significantly more expensive to use than alginate, and depending on the physical properties and viscosity of the particular brand used, these may exhibit more flow than desired for the typical full-arch impressions used for preliminary models. Some have a displeasing taste and can take up to 4 minutes to set, which is time consuming and uncomfortable for patients.
Recently, some dental manufacturers have released impressions materials specifically designed to serve as what could be called an “alginate substitute.” The primary purpose of these materials is to render more accurate, elastomerically-stable, tear resistant impressions than traditional alginate, with many of the already mentioned advantages of polyether and VPS materials.

CASE REPORT
A 38-year-old woman presented with the chief complaint of moderate to severe myofacial pain and frequent migraine-type headaches, particularly in the left temporalis area. The patient was actively engaged in clear aligner orthodontic therapy and noted that though she had occasional headaches and joint pain before, her symptoms had become worse as orthodontic therapy progressed (Figure 1). A complete intraoral and head and neck exam was performed and a comprehensive TMD/myofacial pain questionnaire was completed.

Preliminary Impressions
Accurate full-arch impressions suitable for occlusal assessment and ultimately for the fabrication of a neuromuscular orthotic can be difficult to capture. Because of the variables involved in mounting a neuromuscular case, several anatomical landmarks must be captured to the teeth themselves. The full hamular notch beyond the maxillary tuberosity region must be captured in the event that the hamular-incisive papilla plane is needed to orient the maxillary cast. The anatomical details of the palate must be represented in the impression if a cranial base transfer is necessary. Precise replication of the occlusal anatomy, the circumference of every tooth and the soft tissue surrounding the teeth is mandatory to fabricate a neuromuscular orthotic to assure proper fit and exact occlusal position of the oriented casts at the myocentric bite.
A medium viscosity, addition-curing, elastomeric VPS (alginate substitute) material (Silginat [Kettenbach LP]) was chosen because of its accuracy and dimensional stability, even after multiple pours. In addition, it exhibits an ideal consistency, flow, and ability to distend the soft tissue in the buccal and lingual corridors to capture the required soft-tissue landmarks. The material is dispensed from the Plug & Press Dispenser (Kettenbach LP) efficiently into an impression tray at the precise rate and catalyst/base ration (Figures 2 and 3), and it has the consistency and flow of traditional alginate materials, but is far more dimensionally stable with fewer voids. With a total set time of 3 minutes and a thixotropic consistency that flows under pressure (it does not run spontaneously into the pharyngeal cavity), it is an excellent choice for patient comfort when taking full-arch preliminary impressions (Figure 4). In this case, the detailed and anatomically accurate impressions were nearly void-free, and minimal drags and pulls were evident (Figures 5 and 6).

Figure 7. After a thorough exam, a complete computer-assisted neuromuscular scan was performed.	Figure 8. This A-siliconebite registration material (Futar [Kettenbach LP]) with an adequate working time of one minute and 30 seconds (1:30), flowed evenly and smoothly onto the patient’s teeth.

Figure 9. The bite registration, shown after properly trimming with a lab scalpel and confirmation of the neuromuscular position.

Figure 12. The neuromuscular orthotic on the mounted models.	Figure 13. The seated and adjusted orthotic.

Computer-Assisted Neuromuscular Assessment
Next, the patient was scheduled for a comprehensive neuromuscular evaluation using a computer-assisted jaw tracking device (Figure 7). Preoperative electromyography (EMG) tracings revealed hypertonic muscle activity, particularly in the left temporalis region with dominance over the masseter muscles and early muscle fatigue on clenching. Electrosonographic tracings during repetitive opening and closing revealed either adhesions or posterior displaced articular disks bilaterally upon closing, with bone to bone contact on opening. Jaw tracking scans revealed 3 mm of deviation to the left upon opening, limited lateral movement and sagittal tracings revealed dyskinesic (irregular) and bradykinesic (slow or protective) closure patterns congruent with the EMG and electrosonographic data. This data was collected and stored to serve as a baseline to be compared with post-treatment assessment. The patient underwent one hour of closely monitored transcutaneous electrical neural stimulation (TENS) in which cranial nerves V and VII were stimulated as well as the primary elevator muscle groups and the postural muscles of the cranium.

Bite Registration Technique
Regardless of occlusal philosophy or TMD management philosophy, altering a patient’s interocclusal relationship requires a highly accurate bite registration. Depending on the technique used, recording an exact bite relationship requires a material that has the appropriate elastomeric properties and working time to permit the desired position to be recorded. In neuromuscular dentistry, the myocentric bite is based on quantitative analysis of computer-generated scans and the patient receives TENS along a myocentric trajectory from isotonic rest. In this particular case, an A-silicone material (Futar [Kettenbach LP]) was chosen because, in the author’s opinion, it has the ideal working time and physical properties for taking a neuromuscular bite. This material exhibits minimum resistance as the patient bites together, preventing any displacement. Furthermore, it accurately reproduces the details of the occlusal surfaces and its fully polymerized state exhibits a hard but easily trimmed texture. It possesses many of the physical properties of a definitive crown and bridge impression material and has impressive permanent dimensional stability, virtually eliminating the risk of deformation. With a dispensing time of 30 seconds and a set time in the mouth of 90 seconds, this A-silicone material is an excellent choice for bite registrations that require time for mandibular positioning (Figure 8).
Several bites were taken, ultimately trimmed with a lab scalpel, and reseated in the mouth to cross-check the accuracy and reduced muscle activity. A properly trimmed final bite was used in mounting the models on which the mandibular neuromuscular orthotic was fabricated (Figure 9).

Working Models and Orthotic Fabrication and Delivery
The impressions and neuromuscular bite registration were then sent to the dental laboratory team, and they poured and mounted the models (Figures 10 and 11). Figure 12 shows the neuromuscular orthotic on the mounted models. Note the knife edge detail of the teeth, embrasures, and gingival tissues, as well as the fit of the orthotic on the mandibular model and the proper bite alignment created from the A-silicone bite registration.
The patient was scheduled for a one-hour appointment to have the orthotic seated in the mouth. Fit and alignment were assessed and after 45 minutes of TENS therapy, the patient was seated in an upright position and the final adjustments of the bite (orthotic) were checked (Figure 13).

CONCLUSION
The role of accurate full-arch impressions and bite registrations in the treatment of TMD pain is extremely important. While numerous impression and bite registration materials are available, the benefits of VPS alginate substitutes and A-silicone bite registration materials, such as those described herein, have been illustrated.

Dr. Blank graduated from the Medical University of South Carolina, College of Dental Medicine in 1989, and maintains a full-time private practice in Rock Hill, SC, where he emphasizes complex restorative reconstruction and cosmetic enhancement procedures. He holds an adjunct instructor post in the Department of General Dentistry at Medical University of South Carolina, College of Dental Medicine, and has authored dozens of clinical manuscripts on a variety of clinical techniques and materials. He is a Fellow in the Academy of Comprehensive Esthetics, and an active member of the International Association for Dental Research, the Academy of Operative Dentistry, the American Academy of Cosmetic Dentistry, the Pierre Fauchard Academy, the American Dental Association, and the Academy of General Dentistry. Dr. Blank has lectured throughout the United States, Europe, and in 9 countries in Asia, and holds US Patent for a composite finishing instrument and is the creator of the C.E.B.L. Technique for direct veneer layering. He can be reached at jblank@comporium.net or at carolinasmilecenter.com.

Disclosure: Dr. Blank reports no disclosures.

For far too long, the well understood anatomy and physiology of the head and neck has been only loosely associated with the dental treatment of patients. For many reasons, dentists have isolated the teeth and the pathology of dentition from the functional, dysfunctional, and parafunctional physiology that can cause wear, damage, fracture, abfractions, failure of restorations, and pain for their patients. These traumas and degenerations are but the signs and symptoms of an underlying problem. In the attempt to offer patients the opportunity for the best possible outcome, clinicians will be required to get to the foundational cause of these manifestations of disease, dysfunction, and, too often, despair.
It is the premise of this article that we can simply redirect the focus of the examination processes and the initial care sequences to address the underlying functional physiology. Patients then can be offered the opportunity to deal with their symptoms and problems in a way that will assure them of a pathway to long-term predictable health and dental stability. In addition, by addressing the problems at the level of the causation, we will be able to expand our care to include excellent results for many of our patients with intractable, late or end stage disorders that include severe dental disease as well as head and neck pain, range of motion disabilities, and accelerated aging related to dysfunction and poorly healed injuries.

CATEGORIZING DENTAL DISEASE
The nexus of tooth related problems with musculoskeletal and neurological physiology is at the point where the effects of muscle-related forces are applied to the teeth or to a bolus of food in a way that develops and determines the patterns of muscle activity through the sensorimotor neurology via the brainstem. When the neurology is abnormal (as in chronic pain) or when the muscle patterns are driven by central nervous system requirements (as in parafunction during sleep disturbances) or when the proprioception of the teeth is altered (as in sensitization or dental changes), then the forces are altered between the teeth via the musculature. How these forces are managed, sensed, and adapted to is the essence of force-related dental disease and dentomandibular sensorimotor dysfunction.
The vast majority of dental-related disease can be categorized into 3 primary issues:

1. Bacterial/host response disease (especially periodontitis)
2. Acid breakdown of tooth enamel
   a. Caries
   b. Acidic biofilm
   c. Gastric acid (reflux)
   d. Dietary acid
3. Force overload
   a. Frictional
   b. Compressive
   c. Shear
   d. Bending (abfraction).

Most restorative treatment currently done in dentistry on adults is a direct result of force-related problems. And, of course, aside from external trauma, these abnormal forces are applied to the teeth by the patient’s muscles. The forces that cause the breakdown of the teeth also cause the acceleration of periodontal breakdown and the early breakdown of previous restorative attempts.
Whether we observe open margins, fractures, wedge defects (abfractions), wear, sensitivity, mobility, or failed restorations, there is reliably an underlying force problem at play. We call this “stress in the system.”
Truly, we can redefine the term “malocclusion” to mean “abnormal forces between some or all of the teeth that results in damage to the integrity of the tooth anatomy or the periodontal interface, or resulting in pain to the patient.”
Malocclusion related pain can manifest as hypersensitivity, deep tooth pain, jaw pain, or pain in the head and neck region served via the trigeminal cervical nucleus. This definition of malocclusion does not necessarily exclude other definitions that refer to the interdigitation of the teeth, or the location of centric stops on the teeth. Rather, this definition allows a perspective on occlusion that addresses the direct relationship of functional physiology to the disease and degeneration that we observe and treat.

Force-Balanced Occlusion
There must then be a force-related definition of a normal or healthy occlusion. I would suggest the following definition: “A system of interdental forces that are well distributed around the arch with an unhindered path to closure and to mastication via effective proprioceptive and somatosensory guidance. The interdental forces should be distributed down the long axis of the posterior teeth with the total forces balanced 50/50 right to left during a full closure to interdigitation.”
Additionally, the ability to masticate without working or nonworking interferences within a normal envelope of function distributes muscle activity with both symmetry and synergy. There should be musculoskeletal stability and symmetry of the temporomandibular joints (TMJ) with the discs normally interposed at full closure. The patient is comfortable in rest and in full closure, and the mandibular range of motion is within normal limits.
Many other conditions may also be present to demonstrate normal health, including but not limited to:
• Patient comfort at rest, and in function
• No acute or chronic pain
• Normal cervical range of motion
• Normal posture
• Normal work abilities
• Normal tooth anatomy and mobility
• No exposed dentin
• No dietary restrictions due to dental function.

As we explore further into the realm of “force-balanced occlusion,” we will encounter many other issues that can disrupt the normal function of the musculature. We will see that as patients develop pathology or have dentistry done, there will be changes to the balance and function of the mandible. Whether this is as simple as a sore or sensitive tooth after restoration, or as complex as the creation of an adapted interdigitation to avoid extreme forces, the patient’s proprioceptive system will constantly adapt to changes. This can result in malpositioned or dislocated condyles during mastication or swallowing, clenching, early disc movement that can precede disc displacement, or patterns of self-equilibration to “grind in” the original force balance through self-mutilation.
Occasionally, these adaptive changes will result in the conversion of acute pain to chronic pain. This then will cause the patient to undergo many neurochemical adaptations as well as compensatory muscle activity that can limit range of motion (mandibular or cervical) and/or result in trigger point muscle spasms.
The signs and symptoms of a “malocclusion” can be manifest in the teeth, muscles, or joints. This triad of anatomy we will refer to as the “dental foundation.”
The dental foundation is considered to be out of balance when any of the following conditions exist:
• Accelerated aging or degeneration of the TMJ condyles
• TMJ vibrations indicative of disc movement, disc derangement, or inflammation
• Tooth damage or degeneration related to abnormal forces
• Limited range of motion of the mandible or the cervical spine
• Presence of sore or painful muscles of the head and neck, especially the presence of “trigger points”
• Symptoms of pain that emanate from the structures connected via and controlled by the trigeminal cervical nucleus, especially headache
• Any lifestyle disability related to the teeth, muscles, or joints of the head and neck
• Abnormal forces are detected in the dentition by examination
• Injuries have occurred that affect any of the above structures or activities.
Generally speaking, any time we need to address a patient’s symptoms that are connected to the dental foundation, it would always be in the patient’s best interest to have the foundation stabilized and balanced prior to or as a part of any treatment for the problem. In other words, if any treatment is needed for the patient, the best possible outcome will reside in the approach that builds a balanced foundation as the first step to care.
The objective examination of the patient for the location, timing, and extent of force imbalance must be accomplished whenever the patient exhibits positive findings for force-related problems on the history or physical examination. In the past, this required multiple visits and expense to develop a set of deprogrammed mounted study casts. This mounted study-cast procedure was cumbersome in that it required additional appointments with the patient to pinpoint the force-related problems.

USING T-SCAN TECHNOLOGY IN THE EXAMINATION PROCESS
The T-Scan system (Tekscan) can provide the dentist a timely (nearly instant) examination of the interdental forces in the patient that manifest force-related problems. The T-Scan also reflects the abnormal dysfunction of the musculature directly with electromyography synchronization or indirectly via the center of force patterns and the disclusion timing. The T-Scan then becomes the definitive diagnostic imaging of the force balance and function of the masticatory muscles. The information provided on a 2-minute T-Scan movie includes much useful diagnostic information (Table).
`Certainly many dentists use the T-Scan for efficient and effective occlusal adjustment procedures. However, the optimal and best use of the T-Scan system is in the diagnostic documentation of force-related problems at the time of examination. Patients can best understand their force-related dental disease and any sensorimotor-related pain and headaches when they can view the computerized force analysis of their own mouth. Every T-Scan movie tells a story about the dental foundation, and each story reveals the underlying cause for whatever may be the pathology that is present.

CLINICAL CASE EXAMPLE
The patient, whose photos are represented in Figures 1 to 3, presented for examination as a new patient. Her chief complaints were as follows: the bridge on the right side had never felt correct to her, her front teeth were chipping and looked unattractive, and she had a history of chronic daily headaches.
Examination revealed worn and fractured enamel on the incisal edges of the incisors, a bridge that needed replacement (a pontic for tooth No. 30), and multiple areas of attachment loss and abfractions lesions.

Figure 1. Preoperative retracted smile: This reveals evidence of force-related dental disease: anterior wear, chipping, and misalignment of the teeth. Additionally, there are abfractions lesions and attachment loss on teeth Nos. 6, 11, and 24.	Figure 2. Preoperative maxillary occlusal view: This shows additional evidence of force related problems: multiple teeth with crowns, broken incisal edges on the anterior teeth, and narrow misalignment of the upper arch.

Figure 3. Preoperative mandibular occlusal view: This shows force related problems in fractures around the margins of restorations on teeth Nos. 18 and 19, misalignment and wear on the lower incisors, missing tooth area No. 30, and poor anatomical contours of the restorations on the lower arch.

Since all of these problems were likely to be “force” related, we wanted explore the possibilities and to maximize our ability to communicate with her by utilizing the T-Scan dental force analysis.
In Figure 4, we can demonstrate to the patient easily that there is a front-to-back force pattern. That was indicative of a tight envelope of function. It was explained to the patient that her muscles were working extremely hard to squeeze her lower teeth together with her upper teeth. Additionally, she was carrying 58% of the force on the right side of her mouth. This tight pattern and imbalance in the bite were perpetuating her headaches and causing her to feel like her teeth did not fit together correctly.
In looking at Figure 5, we showed the patient that 25% of all the force in her mouth was being borne by teeth Nos. 1 and 2 against Nos. 31 and 32. In Figure 6, we easily showed the patient that there were towers of excessive force on her right side in the anterior and back on her bridge.
Armed with this diagnostic information, the patient then easily accepted that a plan could be designed to balance her foundation, starting with the excess muscle activity. Her treatment program included several weeks of muscle rehabilitation, followed by a balancing of the dental forces. After her symptoms were resolved, then her restorative dentistry was accomplished in a predictable and comfortable program.

DISCUSSION
Creating a balanced foundation involves more than just balancing forces. It means that we need to proceed down a path that will allow for the most symmetry of the muscles and joints as the initial focal point for care. This is what we call the “pathway to care.” This pathway to care refers to the development of an appropriate sequence to rehabilitate the musculature and the joints as we treat the patient’s symptoms. Much like an orthopedist must balance the rehabilitation of a patient’s muscles, ligaments, and joints with the development of a planned prosthesis, we must approach the most adaptable tissues first which are the muscles, then the joint rehabilitation, and finally we can complete any needed treatment of the teeth.

This rehabilitative approach gives the appropriate time process to each patient depending on the extent of the injury and degree to which the condition has become chronic. Certainly, the patient who has an acute problem can go through a quick rehab assessment and move quickly to the dental restorative process. However, the patient who has a limited range of motion in the mandible or cervical spine will need more time to rehabilitate the musculature, thus minimizing pain and disability prior to dental restoration. In either case, rehabilitation is the mindset of dealing with dental foundation problems through the development of an appropriate pathway to care.

Figure 4. Ts1 Scan: This shows the long center of force tail demonstrating the severe anterior to posterior dimension of closure forces and a very limited envelope of function.	Figure 5. Ts2 Scan: This demonstrates the severe right-sided force imbalance during closure with 25% of the force being borne by teeth Nos. 1 and 2 versus Nos. 31 and 32 during the closure cycle.

Figure 6. Ts3 Scan: This reveals the “towers of force” that are evident in the unbalanced bite with excessive forces being recorded on the anteriors Nos. 8 and 9, and teeth Nos. 1 and 2.

As a patient approaches the rehabilitation, we will often discuss the balancing of the foundation and the balancing of the bite. The balancing of the bite is the one piece of the rehabilitation process that can only be done by a dentist. This means that any patient who has a problem that resides in the teeth, muscles, joints, or in the trigeminal cervical nucleus must be cared for by a knowledgeable dentist to have the best opportunity for success.
Other medical professionals who treat some of these “foundation” problems can only achieve short-term success; this is because they cannot control the afferent signals from the teeth to the trigeminal cervical nucleus. This brainstem pathway (or column) carries all the information regarding headache, head and face pain, and neck pain to the patient’s thalamus and on to the cortex. Approximately 40% of the afferent control into this column comes from the area around the teeth and jaws. In other words, this is the domain of the dentist, and it is the dentist who has the systems to ultimately stabilize the rehabilitations that are necessary for this part of the body.
The essence of all force-related and pain-related pathology in the dental foundation is a dentomandibular sensorimotor dysfunction. All conditions that are mediated by, or dependent on, this major neurological system of the brainstem are interconnected via dendritic synapses that have developed within this trigeminal system of nuclei. As a result, all dysfunction of the mandible, upper 3 cervical vertebrae, and associated musculature, are associated with the somatosensory and sensorimotor neurology of the oral and dentomandibular regions. This, then, is the domain of the dentist.
Although many dentomandibular conditions have a “chicken or the egg” etiology, all therapy for dental foundation imbalance or bite imbalance must be approached comprehensively, dealing with all foundational elements to achieve success. The precise etiology of headache, migraine, head/face pain, or tooth wear is not as important to determine as is the understanding that the “stress in the system” must be managed through comprehensive rehabilitation of the muscles, joints, and teeth.
As dentists begin to “balance the bite,” they will proceed with balancing the forces around the arch through both additive and subtractive procedures. The process of balancing the bite is not a therapeutic end unto itself, but must be developed along with the symmetry and normalization of the condyles and the muscles. This will create and develop a balanced foundation through the rehabilitation process.

CONCLUSION
When all the elements of teeth, muscles, joints, neurology, pain, and force balance are addressed, the patient will have the best chance for an excellent outcome. This rehabilitative approach is the crux of a medical/dental synergy that is grounded in the neurology and neuroplasticity of the human brain, brainstem, and cranial nerves. The elements of the applied neurology of the afferent and efferent pathways that are involved with sensation, proprioception, pain, reflex motor control, and compensatory adaptations can be addressed with a pathway to care that includes a “force balanced occlusion.”
Dentomandibular sensorimotor dysfunction can be effectively managed with this straightforward, systematic approach.

Dr. Montgomery graduated from Oregon Health Sciences University in 1980. He is a member of the ADA, Oregon Dental Association, AGD, International Association of Orthodontics, and Academy of Comprehensive Esthetics. He was a founding faculty and director of education with PAC~live and the Hornbrook Group. He currently partners with Aesthetic Masters and University of Nevada Las Vegas School of Dental Medicine in live-patient hands-on curricula for postgraduate clinical studies. He also is a consultant with Pride Institute. He is on the faculty of Aligntech Institute, training dentists in the Invisalign system. He also is the founder of Cascade Aesthetic Masters Study Club in Oregon. He presents continuing education courses affiliated with the Aesthetic Masters Group in the areas of occlusion and full-mouth reconstruction. He can be reached at mark.montgomery@dentalresourcesystems.com.

Disclosure: Dr. Montgomery reports no disclosures.

Dr. Shuman is president of Pride Institute and is well known in the dental community for his leadership and expertise in the areas of strategic relations, emerging technologies, Internet strategy, practice management, and marketing. The Pride Institute’s goal is to utilize its reputation of integrity and fairness as a foundation in educating the community within the field of emerging technologies. He previously served as vice president of clinical education and then vice president of strategic relations for Align Technology for 7 years. He is a member of Dentistry Today‘s Dental Advisory Board and has been listed in Dentistry Today‘s Leaders in Continuing Education from 2004 to 2008, and he is currently listed as a Leader in dental consulting. He can be reached via e-mail at lshumani@msn.com. Follow Dr. Lou Shuman on Google+, on Twitter (@LouShuman) or subscribe to Lou Shuman’s posts on Facebook.

Disclosure: Dr. Shuman reports no disclosures.

Ms. Morgan serves as the CEO of Pride Institute. She is a dental consultant and international lecturer. Over the years, Ms. Morgan has facilitated the successful revitalization of thousands of dental practices using Pride Management Systems. She can be reached at amym@prideinstitute.com.

Disclosure: Ms. Morgan reports no disclosures.

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Figure 1. Observe the severe anterior wear. This was caused by a forward positioning of the mandible due to an interference on the first premolar (see Figure 2). Figure 2. Observe how one (or 2) restorations in hyperocclusion (left “high”) will deflect the mandible forward when fully closing (see Figure 1). Figure 3. When posterior teeth grind against each other in lateral movements as in group function, excessive wear will occur. Figure 4. When a patient has an anterior open bite, the posterior teeth will grind against each other in lateral movements, generating signs and symptoms of occlusal disease. Figure 5. The appropriate amount of overjet will allow the mandible to have the natural forward swing (envelope of function), without interference. Figure 6. Typical appearance of “thinning” of teeth due to a violation of the envelope of function.

It is a great service for our patients, and a great asset to clinical dentists, to understand how to provide a physiological and mechanically sound occlusion. Fortunately, giving our patients a sound occlusion is not as complicated as it may appear.
Dentists treat patients with a variety of occlusal approaches, from the incredibly meticulous and complicated gnathological approach with a fully adjustable articulator and cusp tripodation to a myofunctional approach all the way to the overly simplified and imprecise natural bite approach. Each modality has a number of followers who believe and feel deeply that the way they do dentistry is the correct way and may even view the other “occlusal camps” as inferior and/or inappropriate.
This intolerance and narrow-mindedness creates an environment that is conducive to neither dialogue nor consensus. The interesting point is, at all spectrums of the scale, clinicians report success and patients do well. Of course, each approach also has its downsides and failures. The differences from camp to camp are many. They start from such things as beliefs surrounding the position of the condyle to issues concerning when the bite needs to be changed. All of the buzzing coming out of the different camps makes many dentists want to just stay away from occlusal treatment altogether; unfortunately, that is impossible, since many things that a dentist does can affects the occlusion of a patient. Fortunately, there are some basic physiological and mechanical rules (or principles) that will apply to any camp, and they are equal to all: the “3 Golden Rules of Occlusion.”^2,3
This article will discuss these relatively simple and scientific-based goals of occlusal therapy. The 3 Golden Rules of Occlusion make the goals of occlusal therapy very clear and simple to comprehend and to define. In addition, when we understand these rules and apply them, it becomes evident that occlusion is very mechanical and not as complicated as some wish to make it, and this should make occlusion less intimidating.⁴ Fulfilling these 3 rules will give our patients a physiologically and mechanically sound bite and the treating dentist clear goals to attain.

The 3 GOLDEN RULES OF OCCLUSION
The 3 Golden Rules of Occlusion can apply to any occlusal philosophy because they are sound physiological and mechanical principles that have been proven by both scientific research and common sense. Nevertheless, when the patient requires occlusal therapy, or when there is a need to reconstruct a bite, the most practical, anatomical, and physiological sound place to position the condyle is into the centric relation position.
The first Golden Rule is to have bilateral and even occlusal contact. The masticatory muscles can generate huge forces, often several hundred pounds of force per square inch.⁵ For this reason, bilaterally even contacts throughout the dentition are mechanically sound, allowing for proper load distribution and a stable occlusion. When a tooth interferes with full closure, it will trigger deflective interferences^6-8 and cause any of the 7 signs and symptoms of occlusal disease such as hypersensitivity, abfractions, mobility, excessive wear or fractures, and muscle or temporomandibular (TM) pain. Posterior teeth deflections may create an occlusal avoidance pattern leading to excessive anterior tooth wear (Figures 1 and 2). Also, in order for muscles to function in coordination, teeth need to contact evenly. It is possible to induce muscle incoordination by introducing an occlusal interferences as shown by Sheikholeslam and Riise.⁹ Additionally, although controversial in the scientific literature, clinical experience shows that occlusal interferences in centric can trigger muscle or TM discomfort, and that removing them will bring about improvement of the symptoms.¹⁰
The second Golden Rule is posterior teeth disclusion, or anterior and canine guidance. Anterior and canine guidance allows for the immediate disclusion of molars and premolars when making lateral or protrusive movements, such as in chewing. This immediate posterior disclusion provides some important mechanical benefits, in that masticatory muscles significantly decrease activity and the amount of force applied to the anterior guiding teeth is greatly decreased.^11,12 Williamson and Lundquist¹³ found that when posterior teeth touch, the muscles can function with full force. On the other hand, when only anterior teeth touch, the forces decrease significantly. An additional mechanical benefit is that since the mandible works as a Class III lever, the further a tooth is from the fulcrum (joint), the less force is applied to it. When a patient lacks this mechanical benefit, during lateral movements, the posterior teeth grind over each other with full muscular force, and it is typical to see these patients with severe signs and symptoms of occlusal disease (Figures 3 and 4).
Finally, the third Golden Rule of Occlusion is an unobstructed envelope of function.¹⁴ During the chewing motion, the mandible does not only swing laterally, it swings forward (protrusively) during the closure movement, returning back into the centric stop. This is called the envelope of function. It varies from patient to patient, but Lundeen and Gibbs15 found that the average was 0.37 mm. The correct amount of overjet allows the space for this protrusive movement to occur without interference (Figure 5). When the overjet is insufficient, or the lingual morphology of the anterior teeth is not concave enough, interference to the anterior path of closure will occur. The consequences of violating this principle while restoring anterior teeth are that patients may complain that their bite feels high or locked in. This often triggers parafunction activity. Also, this interference in the path of closure may cause a scraping of the anterior teeth, resulting in the typical wear pattern, severe “thinning” of incisal edges, or wear of the lingual surface of the maxillary anterior teeth with wear of the facial of mandibular anterior teeth (Figure 6). It can also cause other problems, including mobility, chipping, and fracture of the teeth.

CONCLUSION
Having a clear vision for what a healthy occlusal outcome should be for restorative dentistry is priceless, and the same is true for occlusal therapy. This clear vision, along with defined goals, will allow the clinician to make clear decisions during diagnosis. It will also allow the professional to measure results at the end of treatment, as well as address the severe and rampant problem of occlusal disease.
The 3 Golden Rules of Occlusion are clear, simple, scientifically sound principles. They are physiological and mechanical sound principles that allow the dentist to increase the quality and predictability of any dental procedure.

References

1. Ruiz JL. Achieving longevity in esthetic dentistry by proper diagnosis and management of occlusal disease. Contemporary Esthetics and Restorative Practice. 2007;11:24-27.
2. Ruiz JL, Paul R. Practical occlusion for everyday dentistry. Dentaltown. 2009;10:48-56.
3. Christensen GJ, Ruiz JL. Restorative dentistry: current developments and a look to the future. Dent Today. 2008;27:98-102.
4. Christensen GJ. Abnormal occlusal conditions: a forgotten part of dentistry. J Am Dent Assoc. 1995;126:1667-1668.
5. Gibb CH, Mahan PE, Mauderli A, et al. Limits of human bite strength. J Prosthet Dent. 1986;56:226.
6. The concept of complete dentistry. In: Dawson PE. Functional Occlusion: From TMJ to Smile Design. St. Louis, MO: Mosby; 2007:6.
7. Piehslinger E, Celar RM, Horejs T, et al. Recording orthopedic jaw movements. Part IV: The rotational component during mastication. Cranio. 1994;12:156-160.
8. Gibbs CH, Lundeen HC, Mahan PE, et al. Chewing movements in relation to border movements at the first molar. J Prosthet Dent. 1981;46:308-322.
9. Sheikholeslam A, Riise C. Influence of experimental interfering occlusal contacts on the activity of the anterior temporal and masseter muscles during submaximal and maximal bite in the intercuspal position. J Oral Rehabil. 1983;10:207-214 .
10. Barker DK. Occlusal interferences and temporomandibular dysfunction. Gen Dent. 2004;52:56-61.
11. Manns A, Miralles R, Valdivia J, et al. Influence of variation in anteroposterior occlusal contacts on electromyographic activity. J Prosthet Dent. 1989;61:617-623.
12. Manns A, Chan C, Miralles R. Influence of group function and canine guidance on electromyographic activity of elevator muscles. J Prosthet Dent. 1987;57:494-501.
13. Williamson EH, Lundquist DO. Anterior guidance: its effect on electromyographic activity of the temporal and masseter muscles. J Prosthet Dent. 1983;49:816-823.
14. Dawson PE. Evaluation, Diagnosis, and Treatment of Occlusal Problems. 2nd ed. St Louis, MO: Mosby; 1989:28-55, 434-441.
15. Lundeen HC, Gibbs CH. The Function of Teeth: The Physiology of Mandibular Function Related to Occlusal Form and Esthetics. Gainesville, FL: L and G Publishers; 2005:30.

Dr. Ruiz is the founder and director of the Los Angeles Institute of Aesthetic Dentistry, where he teaches workshops on adhesive and aesthetic dentistry, and occlusion. He is past director of the University of Southern California’s Aesthetic Dentistry Continuum (from 2004 to 2009), associate instructor at Dr. Gordon Christensen’s PCC in Utah. He has had a full-time private practice in the Studio District of Los Angeles for more than 18 years. Dr. Ruiz has published several research studies in the area of adhesive dentistry, many clinical articles, and lectures internationally. He graduated from Universidad National Autonoma de Mexico in 1997. He has made numerous television appearances highlighting his aesthetic dental makeovers, including NBC’s Channel 4 News, ABC’s Vista LA, and Univision and Telemundo. He can be reached at drruizonline.com or via e-mail at ruiz@drruiz.com.

Disclosure: Dr. Ruiz reports no conflicts of interest.

PHYSIOLOGIC ACTION: JOINTS
One of the primary issues with patients in pain is the source. Most experts suggest the muscles are the cause of pain in more than 90% of the cases we see as dentists.⁹ Aside from a recent traumatic injury, that has been our experience as well. By using an E-appliance with its anterior bearing point, we can determine the source of pain and use it as a diagnostic tool.¹⁰ If true unstable internal derangement exists, there will be an increase in pain from using this type of appliance, thus diagnostic for TMJ damage.¹¹
If there is no joint pain, we can move on to joint position.^12,13 This has been another source of controversy with splint use. Capturing the best joint position has been described with several techniques. What’s great about this splint is the practitioner does not need special manipulation skills. By virtue of the splint design, all back teeth contact is removed. With the anterior bearing point and decreased muscle hyperactivity, the joint goes to its most physiologic position without dentist influence.¹⁴
If joint health is a question before treatment, this appliance works well to allow stability, disc variation due to remodeling, and determination of a repeatable position before the restorative phase.

PHYSIOLOGIC ACTION: MUSCLES
Muscles are hyper-activated by working and balancing interferences.¹⁵ This increases forces on the teeth and perpetuates teeth wear, lateral forces on posterior teeth, and pain in muscles due to lactic acid buildup.¹⁶ Single-arch splints designed to help this require precise adjustments so that no posterior tooth contact occurs, other than in an axial direction. Specific jaw manipulation techniques are needed to properly make adjustments so torsionally loading posterior teeth can be avoided.¹⁷ The extra manipulation and adjustment skill required results in many splints functioning poorly by leaving both working and balancing interferences “built” into them. Many good dentists, with all the best intentions for their patients, still struggle with appliance problems, and therefore bite stability.
The E-appliance is designed to eliminate posterior contact and let all inter-arch contact be contained on the flat plane area on the upper-arch splint. The full-arch splints essentially “blind” proprioception. When the lower bearing stylus contacts the flat plane, forces are generated in only the anterior portion of the splint; therefore less muscle pressure results.¹⁸ Without posterior interferences, the jaw positioning muscle (such as the lateral ptyergoid) decreases activity, letting the jaw seat in a natural position for that joint.¹⁹ This allows a release of muscle spasm and results in muscle pain reduction.^20,21 The upper plane is designed to be very flat so that even the most muscular bruxer has little resistance when exerting right and left jaw movements. Both the lower stylus and the upper plane are polished acrylic, so the jaw literally slides right out when resistance is applied.

PHYSIOLOGIC ACTION: TEETH
Another advantage of the E-appliance is that it doesn’t have to be extra tight. Any action on the splint only serves to seat the appliance. No crossover can occur, so there is no need for tight splints to resist that type of jaw movement. When the splint is not as tight as previous single arch appliances, we see better patient compliance. Since the splint covers the entire arch, no one area of the teeth receives excessive pressure from bruxing like some anterior limited-coverage systems. By covering all the upper and lower teeth, mobility and teeth movement are eliminated, and so is orthodontic relapse.²² This will also limit furcation bone loss, diagnosed by periodontists as a condition of periodontal disease often complicated by secondary occlusal trauma.
Dentists have been told if the bite balancing is done right, the teeth will stay in position. Yet that has not been the experience of even the most skilled practitioners. Some patients do not stay balanced; with an E-appliance, the teeth will stay where you have adjusted them over time.
Because the appliance covers all the teeth, wear from clenching is controlled, and complex restorative work is protected.²³ Aesthetic reconstruction can be done on some of the most abusive bruxers if they are wearing this appliance; a small price to pay for controlling the breakdown caused by such damaging jaw movements.²⁴

CASE 1
E-appliance for Holdover Therapy and Pain Management

Figure 1. Preoperative full-face.	Figure 2. Pre-op. Anterior teeth look age-worn.
Figure 3. Pre-op. Worn anteriors flat posteriors.	Figure 4. Pre-op. Occlusal view of fractured premolar.

This 35-year-old female was unhappy with her smile. She had suffered jaw muscle pain for several years and believed that she was grinding her teeth at night. The initial exam revealed worn anterior and posterior teeth; tooth No. 4 had the lingual cusp fractured and required endodontic therapy. The masseter temporalis and lateral ptyerigoid jaw muscles were sore and tender, although no pain was evident in the jaw joints on loading (Figures 1 to 4).
During the initial interview, she reported being previously advised to have a full-mouth reconstruction done, and she was simply not ready to invest that much money. She was looking for an alternative to help her jaw problems, and to also look more attractive.
fter a complete work-up, we agreed to a plan of transitional therapy using composite resin to re-establish harmonious bite function while creating a more attractive smile. Tooth No. 4 needed endodontic treatment and a post-and-core restoration. Splint therapy, using the E-appliance during sleep, was agreed to in this case.
The patient wore an anterior deprogrammer the night before her bite balancing. She then reported for an all-day appointment, consisting of bite balancing, composite additions to teeth Nos. 6 to 11 (covering the middle and incisal two thirds of these anteriors), and rebuilding of tooth No. 4. Hybrid composite was used in all areas since strength was an emphasis during this transitional treatment. Upon completion, full-arch impressions were done for the E-appliance using crown and bridge impression materials. When balancing the bite, we eliminated working and balancing interferences, and therefore reduced forces during the day. The new anterior teeth not only looked better, but also helped establish the anterior guidance lost as a result of tooth wear. The E-appliance was used to keep the teeth from moving in both the upper and lower arches. With the splint’s anterior bearing point, we could reduce nighttime forces, protect all the teeth, and distribute clenching pressure all at the same time, with little adjustment. Her muscle tension and pain decreased during the day, and the E-appliance kept her jaw comfortable and without pain upon waking each morning.

Figure 5. Postoperative at 2 years.	Figure 6. Post-op, 2 years. Stable and attractive with composite resin.
Figure 7. Post-op, 2 years. No breakdown occurring.	Figure 8. Post-op with E-appliance in place.

These 2-year post-op photos show the improved appearance and the stability the E-appliance can help patients achieve (Figures 5 to 8). The additional height of the bearing point is required to account for her increased curve of Spee. This enables her to freely move her jaw at night and avoid any posterior contact.
At a recent hygiene appointment, she reported being ready to begin reconstruction with porcelain; she’s hoping to do this in phases. With this system and the E-appliance stability, we can easily meet her requests.

CASE 2
E-appliance for Stabilizing Full-Mouth Rehabilitations/Occlusions Over Time
Any full-mouth reconstruction comes with a set of complications unique to each case. This 41-year-old male complained about his age-worn smile, jaw pain, and some fractured fillings. Repeated repairs had this patient wondering if there was another and better way. He felt his smile looked bad and that it detracted from his overall appearance; a better-looking smile was a primary concern (Figures 9 to 13).

Figure 9. Preoperative full-face.	Figure 10. Pre-op. Worn and discolored.
Figure 11. Pre-op. Uneven anterior wear patterns.	Figure 12. Pre-op. Cracked and worn posteriors.

Figure 13. Pre-op. Wear rates increase with dentin exposure.

His initial exam revealed many old fillings in various stages of disrepair. Tooth wear, cracks, and temporary patching were also evident in his posterior teeth. He acknowledged that he may clench his teeth, and that he had awakened on some mornings with jaw soreness.
After a comprehensive bite and aesthetic workup, we agreed to restore all the upper and lower teeth. During the work-up process, we found his periodontal health to be quite good. The breakdown was occurring with his occlusion and the restorations designed to protect and restore the teeth.
Laboratory construction of the restorations on precise articulators using specific guidelines requires close communication and common principles understood by both the clinician and the dental laboratory technician. The guidelines for full-mouth rehabilitation cases involve certain preparation, prototypes, and bonding techniques. Each stage was aimed at resolving the aesthetic and occlusal problems. Building the anteriors to look good and also protect the posterior teeth in eccentric movements was the goal of this segment of treatment. Posteriors that contact evenly and at the same time were also important criteria. No contacts should be on slopes so we could avoid hyperactivating jaw muscles. All centric stops were to be in harmony with the patient’s natural jaw joint position. All these goals are common with many cases; yet, on delivery and subsequent follow-up, it is difficult to keep the occlusions stable and functioning exactly where we intend. That is where the E-appliance plays a major role.

Figure 14. Post-op at 7 years. Maintained posterior stops over time.	Figure 15. Post-op, 7 years. The E-appliance eliminates posterior interferences.
Figure 16. Post-op at 7 years.	Figure 17. Post-op, 7 years. Attractive and stable rehab.

Figure 18. E-appliance, showing posterior separation.

Once the case was completed and the bite appropriately balanced, the E-appliance was delivered as usual. Wearing this device will turn off muscle activity and allow the joint to fully seat each night. Avoiding muscle hyperactivity means pain-free jaws in the morning. The splint also keeps the teeth from shifting; therefore occlusal contacts not appropriate for an individual tooth can be easily detected and removed. As a result, daytime occlusal management can be done more simply. At times in the past, we chased around occlusal stops, adjusting and hoping some stable place would finally be achieved. If patients felt good and nothing was breaking, we called this an occlusal “success.” Now, we can apply exacting accuracy by checking for stable tooth contacts, and working and balancing interferences, at hygiene intervals. By using the E-appliance, we have found our patients’ occlusions to be very stable.
The 7-year post-op photos shown in Figures 14 and 15 indicate the absence of eccentric contacts in the posterior, yet solid centric stops remain. This patient has been very comfortable and stable with his occlusion. Unlike before, the treatment that we provided, which included use of the E-appliance, resulted in occlusal stability, thus obviating the need for continual and repeated repairs/patching (Figures 16 to 18). There really was another outcome possibility that proved both predictable and stable!

DISCUSSION
Patient Advantages
Any device that relieves pain is always popular with patients. With the E-appliance, pain reduction is a strong benefit. In our experience, we have also noted that compliance is much better than found with many single-arch (“thick”) systems. Tooth pain and temperature sensitivity resulting from excessive forces is also improved or eliminated. Adults completing orthodontics or complex restorative (as in Case 2) will not experience relapse by using an E-appliance.
The E-appliance system is also helpful when used with restorative treatment. By stabilizing the damaging occlusal conditions, it allows patients to spread out their treatment in phases (as in Case 1). When faced with complex treatment, some patients cannot afford to proceed at all. The E-appliance can prevent further damage from bruxism until they are ready. When combined with preventive hygiene and caries removal, this works well as a “holdover option” for those who desire it.

Doctor Advantages and Protocol
The E-appliances are easy for offices to deliver, since all the design and fabrication of the patented splint is done by Esthetics Unlimited Laboratory. Bite recordings are simple to do; no special manipulation is needed to properly fabricate the double-arch appliance. Curve of Spee is accounted for by the vertical dimension of the splint so that all jaw movements result in posterior separation. In the 2 cases presented here, the stylus and height were adjusted for us by the dental laboratory technician for exactly that reason.
Many doctors have delegated the records and delivery to auxiliary team members. Patients should bring their appliances to hygiene appointments for cleaning and evaluation.
Since the E-appliance is self-adjusting, the follow-up is very easy. Without the stress of precise manipulation, doctors are able to know the best muscle/joint position for the patient with much less effort. Because the design of the E-appliance separates joint pain from muscle pain, it is a very useful tool for dentists to help determine if they should treat the patient or refer to the TMJ specialist.

CLOSING COMMENTS
We have been using the E-appliance in our office for more than 8 years. Since its introduction, it has been retooled and improved over time. In the author’s opinion, appliance therapy for most patients has never been easier.

References

1. Dyer EH. Importance of a stable maxillomandibular relation. J Prosthet Dent. 1973;30:241-251.
2. Beard CC, Clayton JA. Effects of occlusal splint therapy in TMJ dysfunction. J Prosthet Dent. 1980;44:324-335.
3. Burns R, McKinney J, Chase D, Anderson D: Occlusal splint therapy for treatment of internal derangements: retrospective study. J Dent Res. 1983; 62: Abstract No. 1215.
4. Magnusson T, Carlsson GE. Recurrent headaches in relation to temporomandibular joint pain-dysfunction. Acta Odontol Scand. 1978;36:333-338.
5. Quayle AA, Gray RJ, Metcalfe RJ, et al. Soft occlusal splint therapy in the treatment of migraine and other headaches. J Dent. 1990;18:123-129.
6. Kampe T, Tagdae T, Bader G, et al. Reported symptoms and clinical findings in a group of subjects with longstanding bruxing behaviour. J Oral Rehabil. 1997;24:581-587.
7. Eubank JB. Phased treatment for complete dentistry. Dent Today. 2008;27:68-73.
8. Wichelhaus A, Hüffmeier S, Sander FG. Dynamic functional force measurements on an anterior bite plane during the night. J Orofac Orthop. 2003;64:417-425.
9. Mongini F. Assessment of craniofacial pain and dysfunction: a multidisciplinary approach. Cranio. 1990;8:183-200.
10. Bell WE. Temporomandibular Disorders: Classification, Diagnosis, Management. Chicago, IL: Year Book Medical Publishers; 1986.
11. Wabeke KB, Hansson TL, Hoogstraten J, et al. Temporomandibular joint clicking: a literature overview. J Craniomandib Disord. 1989;3:163-173.
12. Ito T, Gibbs CH, Marguelles-Bonnet R, et al. Loading on the temporomandibular joints with five occlusal conditions. J Prosthet Dent. 1986;56:478-484.
13. May BM, Garabadian C. Reducing condylar compression in clenching patients. Crit Rev Biomed Eng. 2000;28:389-394.
14. Manns A, Miralles R, Valdivia J, et al. Influence of variation in anteroposterior occlusal contacts on electromyographic activity. J Prosthet Dent. 1989;61:617-623.
15. Mahan PE, Wilkinson TM, Gibbs CH, et al. Superior and inferior bellies of the lateral pterygoid muscle EMG activity at basic jaw positions. J Prosthet Dent. 1983;50:710-718.
16. Steele JG, Lamey PJ, Sharkey SW, et al. Occlusal abnormalities, pericranial muscle and joint tenderness and tooth wear in a group of migraine patients. J Oral Rehabil. 1991;18:453-458.
17. McKee JR. Comparing condylar positions achieved through bimanual manipulation to condylar positions achieved through masticatory muscle contraction against an anterior deprogrammer: a pilot study. J Prosthet Dent. 2005;94:389-393.
18. Manns A, Rocabado M, Cadenasso P, et al. The immediate effect of the variation of anteroposterior laterotrusive contacts on the elevator EMG activity. J Cranio. 1993;11:184-191.
19. Belser UC, Hannam AG. The influence of altered working-side occlusal guidance on masticatory muscles and related jaw movement. J Prosthet Dent. 1985;53:406-413.
20. Shupe RJ, Mohamed SE, Christensen LV, et al. Effects of occlusal guidance on jaw muscle activity. J Prosthet Dent. 1984;51:811-818.
21. Kerstein RB, Wright NR. Electromyographic and computer analyses of patients suffering from chronic myofascial pain-dysfunction syndrome: before and after treatment with immediate complete anterior guidance development. J Prosthet Dent. 1991;66:677-686.
22. Parfitt GS. Measurement of the physiologic mobility of individual teeth in an axial direction. J Dent Res. 39:68,1960.
23. Kydd WL, Daly C. Duration of nocturnal tooth contacts during bruxing. J Prosthet Dent. 1985;53:717-721.
24. Grippo JO. Abfractions: a new classification of hard tissue lesions of teeth. J Esthet Dent. 1991;3:14-19.

Dr. Orser graduated Loyola University with a BS in psychology, Loyola Dental School with a DDS, and completed a general practice residency from Rush Medical Center. He is a member of the American Equilibration Society and the ADA, and he is an accredited member of the American Academy of Cosmetic Dentistry. He teaches at the Eubank Teaching Institute and is founder and senior partner of Arlington Adult Dentistry in Arlington Heights, Ill. He is a past reviewer of cosmetic articles for the ADA Journal and has previously published in the Journal of Cosmetic Dentistry and Dental Economics. He can be reached at drsorser@arlingtondentists.com.

Disclosure: Dr. Orser has no financial interests in, or benefits from the owners and developers of the E-appliance.

If you are interested in utilizing the E-appliance as a part of your patients’ treatment, contact Esthetics Unlimited Laboratory at (972) 596-1811 or send e-mail to dr.eubank@therightfitdentist.com.

CASE HISTORY

Figure 1. Patient had a deep overbite and no canine-to-canine contact, therefore no anterior guidance. The orthodontist provided us with the preoperative unmounted models, so the true arch-to-arch relationship can only be guessed.	Figure 2. Everything seems fine immediately postoperative (ortho-surgery). But note that models are unmounted. This is therefore not the true arch-to-arch relationship.

Two years prior to her appointment with us, she had been to her dentist and complained of frequent headaches. She was an Angle Class II with severe anterior overbite (Figure 1). Her dentist discussed the fact that her occlusion might be the cause of her headaches and referred her to an orthodontist. The orthodontist explained that it was possible the occlusion could be the causative factor, and in turn explained that not only orthodontics was needed but also maxillo-facial surgery. The oral surgeon confirmed that occlusion might be the problem, but insisted that no promise could be made as to end results.
The patient accepted the treatment plan because nothing else she had tried had helped. A complete orthodontic treatment was done combined with impaction of the maxilla and saggital split advancement of the mandible. Upon removing interarch fixation, the patient had a Class I occlusion and was relatively symptom-free (Figure 2).
However, within a few weeks the anterior bite started to open, and it took only a few more weeks for the mandible to regress to the point where only teeth Nos. 2 and 31 were left in contact, with the bite progressively opening all the way to the other side. Even though the original type of headache was gone, the patient suffered from TMJ pain on the right side, muscle pains, a new type of headache, muscle spasms, opening limited to 25 mm, inability to chew, and, of course, she was quite discouraged. The oral surgeon offered that her mandible “was probably not made to be in the advanced position,” and the orthodontist said just to wait, that things would get back to normal and the teeth would touch again.
The patient’s dentist, upon supplication to do something, fabricated an occlusal splint that relaxed the muscles and gave some relief to the patient. However, the result was temporary, and within 3 months all the pain was back. The patient was then referred to a prosthodontist, who prescribed an MRI of the TM joints. At this time the patient, to whom the suggestion had already been made to visit our office, decided to consult with us.

EXAMINATION

Figure 3. The only teeth touching postsurgically were the last 2 molars (Nos. 2 and 31).	Figure 4. Note separation of patient’s left side in maximum intercuspation (centric occlusion).
Figure 5. Patient’s right side; only the last teeth are in contact. This is maximum intercuspation.	Figure 6. Patient had an otherwise healthy mouth.

Upon examination the patient presented with a severe malocclusion (Figures 3 to 5) with contact on 2 teeth only in the right posterior region, and a 3-mm slide from centric relation to centric occlusion (all on one tooth). She also had an open bite on all other teeth with impossibility to create contact on any other tooth even by mandibular movement. Upon palpation the right TMJ was very tender, as were the lateral pterygoid, medial pterygoid, and attachment of the temporalis at the coronoid process.
Doppler auscultation revealed significantly augmented blood flow on the right side compared to the left side, with no significant noise upon straight opening; but left excursion revealed a click in the right TMJ. The patient also reported light crepitus in the morning. Opening was limited to 25 mm, and lateral excursions were minimal because of pain. The periodontium was healthy, and the 28 teeth present needed no restoration due to decay or fracture (Figure 6). Soft tissues were normal, as were the glands and saliva. At this time the patient had not yet undergone MRI, but had an appointment for MRI.

DIAGNOSIS

The following diagnosis was made: severe malocclusion iatrogenically induced; disc displacement in the right TMJ with recapture upon opening (Piper III A, Dawson Type II A); capsulitis of the right TMJ; muscle inflammation; headache; limited movements; and inadequate masticatory function.

TREATMENT PLAN

Phase I

The first step was to obtain MRI results to eliminate possible clinical misdiagnosis about the state of the TMJs. We feared, even though no clinical signs pointed there, that the cause of mandibular regression and rapid opening of the bite postsurgically might have been severe damage to the condyles, avascular necrosis, or another significant form of rapid bone degeneration.
The next step was to fabricate, as quickly as possible, an occlusal splint equilibrated to centric relation with absolute anterior guidance.
We then wanted to re-evaluate the patient as soon as the MRI was done. Prognosis after Phase I was reserved.

Phase II

Upon receiving the results of the MRI we could confirm that our clinical observations were correct, and the patient had no condylar degeneration. We proceeded to adjust the splint as we had prescribed. The patient was instructed to wear the splint 24 hours a day for a period of 3 weeks and to come back for re-evaluation.

Discussion of Why the Mandible Regressed Postsurgically

In this case, the conclusion that the joints were healthy led us to question why the mandible had so violently regressed. Relapse, the usual explanation, was simply not valid. We suspect that when the divided parts of the mandible were fixated together, the anterior segment was correctly advanced into proper occlusion, but the posterior segments, instead of having the condyles seated in centric relation, were also advanced. If the surgeon, during fixation, does not positively maintain the con-dyles in centric relation, then there will always be regression postsurgically.

Prognosis After Phase II

At this point, because the condyles were confirmed healthy, and the joints therefore were manageable, the prognosis of relieving the patient’s pain was good, considering that prior to surgery the patient had no TMJ pains.

Results of Phase II

Immediately after insertion of the equilibrated splint the patient felt total relief. As long as the splint was worn, there was no pain. This therapy was continued for 3 months to confirm stability.

Discussion of Phase II Results

Technically, phase II was a complete success, as the patient was comfortable and without pain as long as she wore the appliance. However, it was awkward for the patient to wear a splint at all times. She is an accountant in a large company, and meetings occur daily. Also, she found little pleasure in eating with the splint in place. We had to find a better solution. Because it was demonstrated that a proper occlusion was the solution for this patient (as is very often the case), we offered her 3 options.

PHASE III

The first option was an overdenture that could be made to fit the lower teeth. Such an overdenture should be stable and equilibrated to perfection.
Another option was  reconstruction with crowns of the upper, lower, or both arches after studying the possibilities and conveniences with well-made waxups.
The third option was to return to orthodontics and oral surgery to correct the mishap of the first attempt.
After discussion of all possibilities, the patient absolutely refuted the idea of returning to ortho-sugery,  even though this solution offered to maintain her dentition in a natural state. She was unable financially at the time to have crowns made, so she opted temporarily for the over-denture on the lower arch.
As we had suspected, however, even though occlusal comfort was attained with the overdenture, the patient was not totally satisfied with the aesthetics, as the lower anteriors were quite long, and just having “something” in the mouth was an annoyance. The patient began to wear the appliance less regularly, and sure enough the pains came back. Within a few months she returned, seeking crowns.
After wax-ups were made (one waxing on the lower only, the other waxing on the upper only), it was determined that an upper rehabilitation was the more aesthetically pleasing option. To make perfectly sure, however, we took an impression of the upper wax-up, poured Protemp 3 Garant (3M ESPE) into it, and reset the impression in the mouth. We left the temporary uncemented, as it was an aesthetic “tryout” to last only a few days.

Figure 7. Teeth prepared for zirconia-based crowns (Lava [3M  ESPE]). Preps are wide chamfer.	Figure 8. Zirconia-based crowns by technicians Marc Nantais and Michel Bourque of Laboratoire De Porcelaine Dentaire Longueuil.

Figure 9. Note proper alignment of teeth, sufficient depth of bite to create anterior guidance, and proper cusp tip-to-fossa posterior relationship.

During these days the patient was comfortable in all aspects. Her occlusion was perfected and comfortable. She had no pains, had no removable appliance to annoy her, and aesthetics were more than pleasing. An appointment was made, and the 14 upper teeth were carefully prepared (Figure 7) to receive zirconia-based crowns. As all details concerning final occlusion had been tested and retested, predictability was very high and prognosis was excellent. Crowns were cemented using RelyX luting cement  (Figure 8).
At one year postoperatively, even though the patient has been through episodes of daily stress with her job, and even through very high levels of stress as she and her husband were in the process of adopting a foreign child, she has had no pain and has taken no medication for pain. Control ap-pointments at 3 months, 6 months, and one year postoperatively confirmed occlusal stability and total patient comfort. No adjustment has been needed (Figure 9).

CONCLUSION

Figure 10. Cuspid rise right side; no other tooth is in contact. Masseters and temporalis are relaxed.	Figure 11. Cuspid rise left side; the rise starts immediately from maximum intercuspation. Patient cannot perceive any lateral or protrusive contact on posteriors.

This case was special. It illustrates most dentists’ misconceptions about what is a good or bad occlusion and the true influence it has. The orthodontist and the surgeon who treated the patient had no real clue as to whether their treatment would bring relief. If they had taken the opportunity to make the patient an equilibrated occlusal splint, they would have found that a proper occlusion was indeed the proper solution. Their prognosis would have been good instead of uncertain.
If the technical aspect of their work had succeeded, the patient might have been relieved of her pains. But no one would have known the true reason. The orthodontist and the surgeon worked on the assumption that an Angle Class I occlusion is a good occlusion. You can’t get any farther from the truth. Angle’s classification is descriptive, not qualitative. What defines a proper occlusion is not how it looks, but how it functions. In a good occlusion when the patient clenches in maximum intercuspation, the condyles are fully seated in the fossae and properly placed in the non-innervated center of the disc. There is no deviation, no slide. Condyles are in centric relation, teeth are in maximum intercuspation. Centric relation = centric occlusion.
From this centric position, all movements should be guided by anterior teeth. No posterior teeth should touch in any excursive movement, lateral or protrusive. These are the 2 first and basic principles of good occlusion (Figures 10 and 11).
Therefore, in the great majority of cases, this is how a rehabilitated occlusion should be; whether the occlusion is corrected by orthodontics, surgery, equilibration, or prosthetics (removable splints, crowns, bridges, implants), the end result should be the same. The case described in this article could and should have been pretested with an equilibrated splint. Care should have been taken by the referring dentist, the orthodontist, and the surgeon to produce the same occlusion with the treatment.
When the patient came to us, that is what we did. We used an equilibrated splint to test and make sure a corrected occlusion was the solution for the patient. We rapidly concluded it was, and then proceeded to correct the dentition to make it correspond to the same principles we planned in the splint.  There was no guessing. It was highly predictable that the rehabilitation with crowns would produce the same comfort, and actually even more than the splint.
In this specific case we concluded that a proper occlusion was the solution for the patient. Looking at the models taken before ortho-surgery (Figure 1), we know there was no canine contact and no anterior guidance, and we can suspect that there was also a CR-CO slide. This patient should have had a choice. Ortho-surgery was one of the possible answers to the problem. The patient could have had a simple occlusal equilibration with either composite or porcelain added to the lingual of her upper canines to produce the anterior guidance. Another choice could have been to equilibrate the posteriors and crown from one upper canine to the other to correct both guidance and aesthetics. This patient did not necessarily need to undergo orthodontic therapy and surgery. It was an option. Our personal opinion is that in these cases ortho-surgery is the better technical solution. But the ortho-surgery must be correctly done, and the result has to be excellent. The occlusion produced by the treatment has to be close enough to the goal so that either the orthodontist or the referring general practitioner can equilibrate the dentition to perfection once the ortho-surgery phase is completed and stable.
Most general practitioners don’t have discussions with their orthodontist and/or surgeon concerning the end occlusal pattern. Most of us rely on the ortho-surgery team to “decide.” This should not by any means be the case. Be proactive and learn about occlusion; talk about it with your specialists. We have been doing it for years and have progressively gotten our local orthodontists, surgeons, lab technicians, etc to better understand why patients are not comfortable and how to get them comfortable.
Success in occlusal-related problems resides in pretesting and respecting the principles. Our patient now thinks the world of us. We know we just understand occlusion. So can you.

Dr. Aubé graduated from the University of Montreal dental faculty in 1984. He continued at McGill University in a residence program with emphasis on full-mouth crown and bridge rehabilitation. Anterior guidance was already his way of choice. He completed the full program at Dawson Center and studied TMJ anatomy, physiology, and pathology with Dr. Mark Piper. He also completed a research project with the Montreal Migraine Clinic on the effect of occlusal equilibration on tension-type headaches and migraines. He was invited to present the results at a meeting of the American Academy of Restorative Dentistry, and maintains a private practice in Montreal. He can be reached at centredentaireaube@videotron.ca or (514) 526-3294.