The Joint Protective Stabilization Appliance

 
SUMMARY

The Portland TMJ Clinic's joint protective stabilization appliance is a simple and effective way to provide rapid 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 prevent the condyle from access to the inflamed portion of the TMJ during the large biting forces that affect everyone in nocturnal bruxism (clenching and grinding during sleep).  In this manner, the joint protective stabilization appliance acts like a brace for an injured TMJ during its workout, much like you might wear a brace to protect an injured knee during sports.  The first couple of nights of wear should eliminate all the pain and inflammation, but two months of nightly wear is usually needed to ensure that the damaged TMJ has completely healed by pseudodisk formation (anatomical adaptation) and functions like a normal TMJ.  After that healing process is complete, the treated TMJ will no longer need protection, and the joint protective stabilization appliance can be converted into a long-term growth appliance to prevent the problem from returning.  To make the appliance comfortable enough for long term wear, we build in a perfectly passive fit; and to promote healthy tongue posture, we hollow out an area in the front of the palate to fit the tip of the tongue. The cost of the appliance is $1500.

NIGHTGUARDS, made by almost all general dentists, protect the teeth from wear 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.  However, excessive wear of teeth is rarely the cause of a TMJ disorder, because teeth are made for wear.  In fact, teeth with wear are healthier than teeth without wear. Nightguards are designed to prevent wear, - not to protect the TMJs or treat the jaw muscles, so their effect on a TMJ disorder is random. They could make it better, they could make it worse, or they could have no effect on it.  

COMMON STABILIZATION APPLIANCES, made by most TMJ dentists, contact the teeth more evenly than simple nightguards, which helps relax the jaw muscles, but they are still not designed to protect the TMJs. Instead, their contours reproduce those of a natural bite at an increased height, with canine guidance in front and relatively flat contacts in back.  The increased stability can reduce muscle tonus, and the height can stretch the jaw closing muscles, but their main orthopedic effect is propping the jaw open.  If the symptoms are due to overclosure of the jaw, (usually from old dentures or severely worn down teeth), this orthopedic "lift" can provide significant relief.  However the vast majority of TMJ disorders are not due to overclosure.  

OUR JOINT PROTECTIVE STABILIZATION APPLIANCES protect damaged TMJs by means of anti‐retrusive ramps, which prevent the back ends of the mandible (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 first dragged into the joint space by dislocation of the disk, they acquire all the characteristics of a chronic bruise - with blood leaking out of vessels, swelling, heat, and pain.  A joint protective appliance protects that area by preventing the condyles from accessing it through the use of anti-retrusive ramps.  

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As seen below, anti‐retrusive 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 photo below shows an anti-retrusive ramp just beginning to engage the front teeth as the patient closes into the appliance.  Further closing will slide the mandible forward away from the inflamed TMJ.

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The angle of the anti‐retrusive 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 freedom of movement.  Steep ramps are used when more TMJ protection is needed, such as when a TMJ is acutely inflamed.   Correctly designed anti-retrusive ramps should enable you to clench forcefully in any jaw position without experiencing the pain that you experience when you clench forcefully against your natural teeth, because your condyle is prevented from even accessing the bruised area. If the damaged TMJ requires more joint protection than the anti-retrusive ramps can provide, you'll need a telescopic (Herbst) appliance.

PIVOTING 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 pivoting is only a short-term measure, because the pivot will wear down quickly or traumatize the supporting teeth.  After a week, if the pivot is still high, it should be removed.

CONVERTING TO A LONG-TERM USE APPLIANCE – After the damaged TMJ has not been inflamed for at least two months, it should be fully healed and no longer needing mechanical protection.  At that point, your joint protective appliance can be converted into an appliance that treats your jaw muscles while optimizing your facial growth to prevent the symptoms from returning.  Flat plate appliances give the mandible a full range of motion, which promotes muscle health.  Front flat plate appliances gradually and steadily reduce restrictive overbites.  Full arch flat plate appliances are preferred in the few people who have little or no overbite.  The conversion to a flat plate appliance can be made at one appointment using our in-house lab for $350.  Also, at that stage, various orthopedic features can be added to promote horizontal facial growth, prevent the mandible from continuing to rotate down and back into the space needed for the pharyngeal airway, or eliminate other growth restrictions.  In people with narrow palates, the joint protective stabilization appliance can be converted into a palate expansion appliance.  In people who also need some teeth straightened, wires and springs can be added.  Later any of these appliances can be easily adjusted to fit around new dental work or implants if necessary.