The Joint Protective Stabilization Appliance

 
SUMMARY
The Portland TMJ Clinic's joint protective stabilization appliance is the simple way to provide symptom relief when there is inflammation present in one or both TMJs.  This oral appliance 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 by preventing the condyles from access to the chronically bruised retrodiskal tissues.  In this manner the joint protective stabilization appliance protects injured TMJs much like a brace protects an injured ankle or knee.  If you keep walking on an inured ankle or knee, it can't heal.  When you lie down, you get off your injured ankle or knee 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.  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.  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 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 rehabilitate 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
The stabilization appliances that are commonly 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 still do little to protect the TMJs.    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, (usually due to 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 
Our joint protective stabilization appliances protect 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.  Joint protective stabilization appliances protect these vulnerable retrodiskal areas by preventing the condyles from being able to access them.  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.  If the appliance is properly designed, you should be able to clench and grind forcefully against it without experiencing the pain that you experience when clenching or grinding forcefully against your natural teeth.

 

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.

 
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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 joint protective stabilization 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 
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 heightened platform elongates them anatomically.  The goal is to restore these muscles to their normal resting lengths.   The process can be assistsed 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 if the appliance is made correctly in the first place.  Any problems with the fit will be fixed without charge.  However, any changes to the orthopedic design that may be needed due to changing circumstances will usually require a laboratory charge.  For example, if your joint protective stabilization appliance does not provide significant relief within days, it may need a change in the heights or angles of the joint protective ramps or a conversion into a different type of appliance.  
 
CONVERSIONS
Many people with an inflamed TMJ initially require a joint protective stabilization appliance to relieve their acute symptoms; but later, after the inflammation is resolved, they can benefit most from a front flat bite plate appliance to reduce the overbite and optimize 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.