The Joint Protective Stabilization Appliance

 
SUMMARY

The Portland TMJ Clinic's joint protective stabilization appliance is the most effective and inexpensive way to provide symptom relief when there is inflammation present in one or both TMJs.  It fits over all the upper teeth and contacts all the lower teeth on a bite surface that has been orthopedically sculpted to protect the TMJs during sleep, much like a brace protects an injured ankle or knee during sports. Usually wearing it nightly for a week is all that an injured TMJ needs to heal, but continuing to wear it protects the TMJs as well as the teeth and the jaw muscles.  Thus, to make it comfortable enough for long term wear, we build in a perfectly passive fit and we hollow out an area up front for the tip of the tongue to allow normal tongue posture.  The cost of the appliance is $1100.

NIGHTGUARDS are simple oral appliances made by general dentists to protect the teeth from wear during sleep by interposing a layer of plastic between them.  When a relatively soft material (plastic) is placed between two harder materials (teeth), all wear occurs on the softer material, so the wear occurs on the plastic rather than the teeth.  However, nightguards are not designed to protect the TMJs or treat the jaw muscles, so their effect on TMJ disorders is random. They could make the problem better, they could make it worse, or they could have no effect on it.  

COMMON STABILIZATION APPLIANCES that are usually made by dentists to treat TMJ disorders have some advantages over simple nightguards. Stabilization appliances stabilize the teeth by covering all the uppers and hitting all the lowers, and they can stretch tight jaw muscles by their height, but they are not designed to protect the TMJs. Instead, their contours simply mimic those of a natural bite, with an overbite in front and relatively flat contacts in back.  Thus their only orthopedic effect is propping the jaw slightly open.  If the symptoms are due to overclosure of the jaw, (primarily from old dentures or severely worn down teeth), this slight orthopedic "lift" can provide significant relief.  However the vast majority of TMJ disorders are not a result of overclosure.  

JOINT PROTECTIVE STABILIZATION APPLIANCES also work by protecting injured TMJs from the effects of nocturnal bruxism (clenching or grinding) much like a brace protects an injured ankle. If you keep walking on an inured ankle, it can't heal.  When you lie down, you get off your injured ankle for 8 hours, and in some cases you may need to stay off it for a couple of days.  However, lying down does not get you off your TMJs. The jaw system undergoes its biggest workout during sleep.  A joint protective stabilization appliance gets you off a damaged TMJ during this workout.

The appliance gets you off the damaged TMJs by incorporating anti‐retrusion ramps that prevent the back ends of the lower jawbone (the condyles) from striking the chronically bruised retrodiskal (behind the disk) tissues located between the condyle and the front of the ear.  These retrodiskal tissues are very vascular, because they were designed to supply circulation to the metabolically active TMJs. When dragged into the joint space by dislocation of the disk, these tissues acquire all the characteristics of a chronic bruise - with blood leaking out of vessels, swelling, heat, and pain.  Properly made joint protective stabilization appliances enable you to clench and grind forcefully without experiencing the pain that you experience when clenching or grinding forcefully against your natural teeth.

In most cases, the appliances do not hold your lower jawbone any further forward than your natural bite. They simply prevent it from dropping back too far during sleep when gravity tends to pull it back toward the inflamed retrodiskal area.  Thus they are intended to stabilize rather than to change your bite.

As seen below, anti‐retrusion ramps are often located just behind the front teeth. They are also occasionally located behind the molars or around missing teeth if there is space available.  The optimal location of the ramps for each patient  depends on the direction of the TMJ dislocation, the disk shape, and the condition of the teeth. 

The angle of the anti‐retrusion ramps determines the degree of TMJ protection they provide. Shallow ramps are used when inflammation is minor and the symptoms are more muscular, because muscles benefit from a wide range of movement.  Steep ramps are used when more TMJ protection is needed, such as when a TMJ is acutely inflamed.   Still greater TMJ protection requires a telescopic appliance as described in a separate file.

PIVOTING

When there is a lot of inflammation in a TMJ, a pivot can be added to the appliance over the last molar on the side of the inflamed TMJ to provide quick temporary relief.  The pivot is a little high spot that should hit slightly before all the other teeth and thereby distract the inflamed joint.  The relief of pain from biting on the pivot should be immediate, but the pivot is only a short term measure, because it will soon wear down.  

STRETCHING THE JAW MUSCLES 

Like common stabilization appliances, joint protective stabilization appliances stretch out tight jaw muscles by creating a tall and stable bite surface to brux against during sleep. The forceful contractions of the jaw closing muscles against a tall platform serves to stretch them while you sleep.  The process can be assisted by ice-and-stretch, myofascial release, and other physical therapy procedures used to treat tight muscles in other parts of the body.

ADJUSTMENTS

Adjustments should not be necessary.  Any problems with the fit will be fixed without charge.  However, changes to the orthopedic design, such as altering ramps or changing the bite surface, may require a laboratory charge for the office visit.    

CONVERSIONS 

Many people with an inflamed TMJ initially require a joint protective stabilization appliance to relieve the acute symptoms; but later, after the inflammation is resolved, they can benefit most from a front flat bite plate appliance that reduces the overbite and optimizes facial growth.  In such cases, the stabilization appliance can be converted into a front flat bite plate appliance at one appointment using our in-house lab for $250.  The stabilization appliance can also be converted into a functional orthodontic appliance in order to maintain the TMJ protection while moving the teeth into positions that will eventually serve to provide natural TMJ protection.