Orthopedic Treatment

When TMJs are inflamed, mandibular orthopedics can protect the bruised retrodiskal tissues, eliminate the inflammation and thereby stop the reflex jaw muscle bracing.  Once the TMJs are no longer inflamed and the occlusion is stable, direct treatment of the jaw muscles can eliminate any remaining myogenous symptoms, and the whole masticatory system can be rehabilitated to acquire healthy function.  Healthy function then produces stable adaptation that is resistant to injury.  

Different types of TMJ disorder conditions require different types of mandibular orthopedic appliances and treatment modalities.  Our most commonly used are outlined in the following text and described in detail elsewhere on this website.  These include: 

  • Joint protective stabilization appliances
  • Joint protective telescopic appliances
  • Pivoting for unilateral condylar distraction
  • Orthopedic disk recapturing
  • Maxillary front flat bite plate appliances
  • Thin rubber occlusal cushion appliances
  • Bite restoring appliances
  • Occlusal stabilization
  • Occlusal alteration
  • Functional orthodontics
Our in-house dental laboratory allows Dr. Summer to quickly change the orthopedic features of an appliance whenever it becomes necessary.   For example, patients with an inflamed TMJ need a joint protective stabilization or telescopic appliance initially; but later the same appliance can be changed into a front flat plate appliance to gradually reduce a deep overbite.  
 
Our in-house lab also enables us to quickly repair broken appliances, rebuild a bite surface that has worn down, and make appliances overnight for people who are in severe pain or have traveled long distances for treatment.  Because we can easily repair broken appliances, we don't need to add unnecessary thickness.  Most people would rather have an appliance that is no thicker than needed to provide the desired therapeutic effect, even if accidentally sitting or stepping on it could break it.    Because we use polyvinyl-siloxane (PVS) crown and bridge material for all our impressions and bite registrations, we maintain an accurate mold that we can use for repairing or remaking appliances.
 
Unnecessary thickness creates a distalizing influence on the mandible by distalizing the tongue. Since the tongue has no bone of its own, its base of operation is the mandible; and anything that causes retrusion of the resting posture of the tongue can cause retrusion of the resting posture of the mandible. In studies of growing monkeys, placing a block of acrylic in their palates caused them to grow long narrow faces, because it forced their tongues to acquire a more inferior and retrusive resting posture, which then forced their mandibles to also acquire a more inferior and retrusive resting posture.  To avoid distalizing the tongue and mandible, in addition to eliminating unnecessary thickness, we hollow out an area just underneath the bite plate at the front of the palate to fit the tip of the tongue. 
 
PASSIVE FIT 
Oral appliances made by commercial labs are not only too thick, but also too tight, especially around the anterior teeth. Plastics all shrink when they set, usually about 3%.  The shrinkage of plastic in a horseshoe shaped dental appliance squeezes the teeth inward, especially at the front of the arch.  That pressure on the teeth causes reflex tightening of the jaw muscles, just as TMJ inflammation does.  It also forces the teeth out of their rest positions.
 
Initially the teeth rebound every day, shifting back and forth between daytime and nightime positions, but eventually they shift.  The resulting inadvertant orthodontics makes the appliance more comfortable, but it can also exacerbate the distalization of the mandible and thereby exacerbate the very problem that we are attempting to solve.
 
Some dentists try and avoid the discomfort from appliance tightness by making their appliances fit on the mandibular arch.  The mandibular teeth are less sensitive to pressure, because they are all planted in one dense piece of cortical bone instead of two membrane bones meeting at a long suture.  However, lower appliances worn during sleep can destabilize bites, because they function as partial coverage appliances.  Unless the patient has a class 3 occlusion, bruxing on a lower nightguard confines all axially directed forces to the posterior teeth and removes them from the anterior teeth. As a result, a period of extreme bruxism can cause extrusion of the anterior teeth, intrusion of the posterior teeth, and a sudden increase in overbite. The overbite can increase so much that it produces a posterior open bite.
 
Some dental manufacturers have responded to the complaints of excessive tightness by manufacturing a plastic that can be softened in hot water just before placing it in on the teeth. Such preheating prevents insertion pain, but not the inadvertent orthodontics that results from forcing teeth out of their rest positions every night.
 
Other dental manufacturers have responded to the complaints of tightness by manufacturing a plastic with a soft rubber inner liner.  The rubber feels more comfortable than hard plastic, but it requires additional thickness without adding strength.  In addition, the rubber is prone to delaminate, because it's difficult to bond rubber and plastic.
 
We use a special block-out process during the fabrication of our appliances to create a passive fit.  Leaving the teeth in their rest positions makes the appliances comfortable enough to wear on a long term basis and also prevents iatrogenic tooth movement. 
 
JOINT PROTECTIVE STABILIZATION APPLIANCES 
While common maxillary stabilization appliances are built around a flat posterior occlusal surface bordered by steep anterior and lateral guidance, our joint protective stabilization appliances have a central bracing area bordered by anti-retrusive inclines that create an articular surface against which the jaw muscles can exercise and brace without driving the condyles into the chronically bruised retrodiskal tissues.  Steep anti-retrusive inclines or telescopic appliances are used when more joint protection is needed, and shallow inclines are used when there is less need for joint protection and more need for muscle rehabilitation.   Joint protective stabilization appliances are described in more detail in THE JOINT PROTECTIVE STABILIZATION APPLIANCE and THE JOINT PROTECTIVE TELESCOPIC APPLIANCE under SPECIFIC TREATMENTS.
 
TEMPORARY JOINT PROTECTIVE STABILIZATION APPLIANCES
When we don't know if a patient's symptoms are due to a TMJ disorder, we can make a temporary diagnostic version of a stabilization appliance at chairside using a thermoplastic (rather than boil-and-bite rubber) before we undertake more costly treatment.  For example, severe headaches (including common migraines) are often caused by TMJ disorders, but there's little a patient can describe about his or her headache that will identify its cause.  If wearing the temporary appliance every night for a week relieves the headaches, there’s a good chance that mandibular orthopedics can provide lasting relief.  
 
PIVOTING  can be added to almost any type of appliance or even the natural teeth to provide quick relief for an inflamed TMJ by distracting the affected condyle.  To be effective, the pivot must be unilateral and located distal to the first molar, where the center of force of the mandibular elevator muscles is located.  A correctly placed pivot allows the patient to bite forcefully without experiencing the pain produced by biting forcefully on the natural teeth.  However pivoting can place a lot of pressure on the distal molars, therefore it is only a short term treatment modality for acute arthrogenic TMJ disorders.

TELESCOPIC APPLIANCES  have several advantages for protecting damaged TMJs. The hardware that provides the protection is located between the teeth and the cheeks where it cannot interfere with normal tongue posture. Having all upper and lower teeth embedded in acrylic prevents any unwanted tooth movement.  In addition, telescopic appliances can include a stabilization type of bite that contacts all around the dental arch, a front flat plate type of bite that hits only the mandibular anterior teeth, a unilateral pivot to distract a condyle from an inflamed TMJ, and other therapeutic occlusal surfaces.

Unlike the Herbst (and SUAD) appliance telescopic hardware, which was designed more than a half century ago for orthodontic bite jumping in children with class 2 malocclusions, we use telescopic hardware that was designed for adults.  Its advantages include a lower profile for comfort because the components are flattened to fit the buccal vestibule, freedom of mandibular movement laterally to ensure long term TMJ  health, and micro-adjustability on each side by the patient at home in .014” increments without special tools.    

UPPER FRONT FLAT PLATE APPLIANCES are employed when the TMJs are already in full adaptation and the jaw muscles remain in contracture.  These appliances have a bite plate surface that is roughly parallel with the orientation of the superior lateral pterygoid muscles, the primary positioners of the mandible on a horizontal plane to better enable those muscles to control the position of the mandible.  

Upper front flat plate appliances worn during sleep have short term and long term effects.  From the first night they are worn, they significantly reduce the strength of nocturnal bruxism. Over the course of weeks, they deprogram the jaw muscles in order to reveal an unstrained mandibular closing trajectory that can be used to evaluate the health of the occlusion.  Over the course of years, they redirect the large compressive forces of nocturnal bruxism onto the anterior teeth in order to intrude them and thereby gradually reduce overbite.

When the joints are no longer inflamed, front flat plate appliances often eliminate headache.  We don't understand much about the mechanisms behind headaches, but we do know that the elevator muscles can apply significant pressure to the head during nocturnal bruxism, and front flat bite plate appliances reduce those forces by about half.  Compared to the NTI appliances, which also eliminate posterior occlusal contacts in order to diminish the jaw muscle forces during nocturnal bruxism, the front flat plate appliance is more stable and less likely to cause unwanted tooth movement.

BITE RESTORING APPLIANCES  usually take the form of two unilateral acrylic segments that fit tightly over the posterior teeth and are used to refine and try out a new proposed occlusion.  In most people they are worn for at least a couple of months to be sure the new occlusion is effective and to allow a little wearing in that improves the fit, especially in lateral excursions used for chewing. 

RUBBER OCCLUSAL CUSHION APPLIANCES are used days to relieve jarring occlusal impacts in people who have neuromuscular systems that have been sensitized by chronic pain and to cushion the exercise template in people who clench on unstable occlusions.  These inexpensive appliances do not impair speech.  However, rubber appliances should not be worn during sleep, because they evoke chewing activity, usually coupled with dreams of eating.                  

OCCLUSAL STABILIZATION may be needed for long term TMJ health, because a stable occlusion gives the mandible a consistent home base that enables the TMJs to acquire the same goodness of fit found between the articulating components of all healthy joints.  In TMJ disorder patients, occlusions are frequently destabilized by disk displacement or degenerative remodeling, both of which shorten the affected condyle, or by TMJ swelling which effectively lengthens the affected condyle.  Frequently TMJ disorder patients notice occlusal fluctuations due to periodic shifting between these conditions.  After the inflammation is resolved and the joint surfaces are stable (no longer degenerating), restabilizing the occlusion may involve reducing high spots, building up low spots, moving teeth, or any combination of  these.  The choice depends on face height and the condition of the teeth.  Stabilizing bites is discussed in THE ROLE OF THE BITE under TMJ DISORDERS.  Occlusal stability and other aspects of occlusion are explained in great detail in the OCCLUSION files.

OCCLUSAL ALTERATION by changing the location of the central bracing position of the mandible (ICP or MI), involves dental work that can be expensive, therefore this modality is only used when it is necessary to relieve the symptoms or when the occlusion needs reconstruction anyway.  It can be necessitated by iatrogenic dentistry, loss of tooth structure, or symptomatic bite strain.  

OCCLUSAL REBUILD is frequently needed in patients who have been previously treated with an oral appliance that they were told to wear on a full time basis and which they wore for long enough to cause the opposing dentition to shift until its occlusal contours fit the surface of the appliance rather than the surface of the opposing natural teeth.  When the appliance is removed, there is no longer a stable natural occlusion.  In treating these cases, providing sufficient occlusal support to allow freedom from daytime wear of the oral appliance is the first step toward finishing the TMJ treatment. Occlusal rebuild can also be necessitated by excessive wear, tooth loss, or the mandible outgrowing the occlusion as is occasionally seen after using a jaw protrusion appliance to treat sleep apnea. 

We allow a period of time during which the patient can wear in and test out the new therapeutic occlusion before making it permanent by transferring it to the natural teeth.  First the proposed new occlusion is created on a provisional basis using tight fitting unobtrusive unilateral removable bite restoring appliances that don’t impair speech and can be worn all day including while eating.  After that new occlusion has proven effective at eliminating the symptoms for at least a couple of months, it is usually transferred to the teeth by bonded composite resin onlays for a provisional period.  Finally, after more stabilizing and refinement of the new occlusion, the composite resin is replaced with gold or porcelain, usually performed by the patient’s general dentist with Dr. Summer providing any support required.  

ORTHOPEDIC DISK RECAPTURE  may be needed for patients who find that nothing provides relief as long as a TMJ disk keeps shifting in and out of place.  Finishing a disk recapturing case requires permanently changing the occlusion, so this treatment is only used when simpler treatments have failed and the prognosis for recapture is excellent or when most of the posterior teeth need restoration anyway.  To help identify anatomical features affecting the prognosis for disk recapture, Dr. Summer collaborated with the leading TMJ radiologist to perform and publish a study using before and after MRI on 119 joints undergoing this treatment.  Reprints of this study are available by request.

Many of the early attempts at orthopedic disk recapture in the 1980's and 1990's failed, because the treating dentists did not understand how to reconstruct a new occlusion that maintained the correction.  Frequently the teeth need contours that are at least slightly different from those seen on natural teeth, requiring extensive communication with the dental laboratory.  

FUNCTIONAL ORTHODONTICS 

For treating and for preventing TMJ disorders, functional orthodontics has important advantages over esthetic orthodontics (braces and invisalign). Removeable oral appliances can support the mandible in an orthopedically ideal position while simultaneously moving the teeth into positions which can produce a stable intercuspal position there.  The appliances can also stimulate jaw muscle development by protecting damaged TMJs and providing an ideal template for jaw muscle exercise.  Palatal expansion can be added to enlarge the nasal airway or to increase the space available for crowded or newly erupting teeth. Gradual palatal expansion can be accomplished effectively and retained in adults if the post treatment occlusion is stable and functional.