Managing the Arthritic TMJ PDF Print E-mail
Written by Dr. John Summer, TMJ Expert, Portland, Oregon   

If a TMJ disk dislocation has advanced beyond the stage where the dislocated disk can be recaptured (restored to its proper location), that TMJ is very likely to show X-ray changes (such as bone spurs, erosions, lipping, or flattening) which makes it fit the definition of an arthritic joint. That label makes the condition sound serious, but the prognosis may still be excellent.  These joints eventually heal by a natural adaptation process in which the chronically bruised retrodiskal (behind the disk) tissues transform into a pad of disk-like tissue which can functon much like a true disk and can last your whole life.  This disk like tissue is so much like a true disk that it is called a “pseudodisk”.  The adaptation which leads to pseudodisk formation can be achieved by ignoring the symptoms until they go away, managing the symptoms until they go away (using supportive treatments such as drugs, physical therapy, relaxation, nutrition, massage, targeted exercises, acupuncture, aerobic exercise, etc.), or using orthopedic mechanics to protect the injured TMJ to facilitate the natural healing process and eliminate the symptoms more rapidly.

 NATURAL ADAPTATION
TMJ disorders can certainly cause severe and longlasting symptoms, but the good news is that they are self-limiting.  The natural course of a disk dislocation consists of gradual arthritic changes accompanied by fluctuating symptoms that eventually disappear with age.  The primary reason for this “burning out” of symptoms with age is fibrosis of the retrodiskal tissues.  This fibrosis process is illustrated below.    
alt

The retrodiskal tissues adapt by undergoing an anatomical transformation.  Originally the retrodiskal tissues contian extensive blood and nerve supply.  After dislocation of the disk traps them between the lower jawbone ends (the condyles) and the skull, these retrodiskal tissues change to adapt to their new functional environment.  Initially, during the symptomatic phase,  they develop all the characteristics of a chronic bruise - swelling, heat, pain, and blood leaking out of the vessels and into the tissues.  However eventually the retrodiskal tissues adapt to the repetitive bruising by transforming into a  fibrous pad of scar tissue that functions as a pseudodisk.

SURGERY
The only TMJs which don’t eventually adapt successfully are surgical failures.  TMJ surgery is frequently successful, but failures can be disasterous, because the build-up of scar tissue prevents natural adaptation.  Further surgeries are necessary to clean out the scar tissue, but the chance of eliminating the pain decreases with each successive surgery.  For that reason, according to insurance company statistics, the primary indication for TMJ surgery is previous surgery, and even the oral surgery journals warn that open TMJ surgery should be considered a last resort and attempted only after all other treatments have failed.  
 
Arthroscopy and arthrocentesis are new types of surgeries that don’t involve the same risk of failure.  Instead of cutting the joint open, the surgeon inserts two little tubes and uses them to flush out the inflammatory byproducts.  Such flushing can provide quick temporary relief of symptoms by interrupting a self-perpetuating cycle of tissue damage and jaw muscle tightness.  However, arthroscopy and arthrocentesis do not create structual changes.  If they are not combined with some orthopedic or behavioral changes which address the cause of the problem, the symptoms are likely to recur in time.
 
MEDICAL MANAGEMENT
One common way to treat TMJ disorders is to allow the arthritic process to run its natural course while “managing” the occasional periods of severe symptoms by means of short term and supportive therapies. There are a large number of these short term and supportive therapies, ranging from medication to meditation and from sophisticated electronic devices to simple home care.  Some management techniques, such as nutritional supplements and stress relief, work by enhancing the body’s natural adaptive capacity.  Other management techniques simply relax the muscles.  Even arthroscopy and arthrocentesis may be used as management tools to get through bouts of particularly severe symptoms.
 
MUSCLE TREATMENTS
Until the mid 1980s, most TMJ disorders were “managed” by treatment of the jaw muscles using physical therapy, relaxation, medications, and flattening teeth to eliminate high spots.  Such treatments sometimes provided good short term relief, but they rarely eliminated the problem.   TMJ dentists were warned not to tell patients that the problem could be eliminated by treatment.
 
When MRI became widely available, we realized why these simple muscle treatments had frequently failed to provide longlasting relief.  Most of our patients had at least one damaged TMJ which caused the jaw muscle tightness to keep returning because of neuromuscular reflexes.  Every joint is wired to the muscles which cross that joint by a reflex which automatically responds to cellular damage in the joint by increasing tension in the muscles which cross that joint.  During our evolution, this so-called “arthrokinetic reflex” served to stabilize injured joints by limiting their range of motion and thereby give them a chance to heal.  Such arthrokinetic bracing can be seen in the way your leg muscles automatically start limping when you try to walk on an injured ankle. The muscles which cross the TMJs are the jaw muscles, so the tension in the jaw muscles is profoundly influenced by the conditions in the TMJs. 
 
While the arthrokinetic reflex was designed to protect acutely injured joints, a TMJ with a dislocated disk is a chronically injured joint, and the chronically triggered arthrokinetic reflex can cause more problems than it solves.  Tightening of the jaw muscles increases the pressure between the uncushioned bones which causes increased TMJ tissue damage, and that damage in turn triggers further tightening of the jaw muscles, so a vicious cycle ensues.  
 
ORTHOPEDIC TREATMENT
In order to stop the ongoing tissue damage, orthopedic mouth appliances treat the TMJ according to orthopedic principles that also apply to joints in other parts of the body.  The ongoing bruising in the TMJ is prevented by precisely controlling the position of the lower jawbone using various removeable mouth appliances and occasionally also changes in the natural bite.  The aim of orthopedic treatment of the TMJ is to facilitate the natural adaptation process so that it requires only weeks or months rather than years or decades.
 
TMJ  PROTECTIVE NIGHT APPLIANCES
One of the central principles of orthopedic treatment of the TMJs involves the use of a night appliance which  protects the vulnerable retrodiskal TMJ tissues from damage during nocturnal clenching or grinding by preventing the back ends of the lower jawbone (the condyles) from repeatedly bruising the retrodiskal area.  Since joints depend on movement for their circulation, the night appliances are designed to allow the lower jawbone a good range of motion in all directions other than retrusively (backward), and range of movement retrusively is restricted only in the direction and to the degree necessary for healing.   For one examply, if only one TMJ is vulnerable, only the condyle of that side of the lower jawbone may need to be prevented from excessive retrusion.  For another example, if the disk is dislocated to one side, the lower jawbone may need to be protected from movement to that side.
 
The amount of joint protection provided by a night appliance  varies from very little protection provided by a traditional nightguard to a very high level of protection provided by a telescopic appliance.  Other appliances fall in between.  The level of TMJ protection provided by a stabilization appliance depends on the length, location, and steepness of the ramps.
 
alt
 
Telescopic appliances also protect the teeth better than other appliances.  All the upper and lower teeth are completely embedded in the plastic, so all the force applied by the jaw mjuscles is spread out evenly among all the teeth.   This feature not only prevents impact trauma, it also prevents directional tooth pressures which frequently cause adverse tooth movement in unstable appliances or bite destabilization in lower appliances worn at night.
 
The final advantage of telescopic appliances is that they don’t impede on tongue posture the way other appliances do, because the telescoping mechanisms rest between the teeth and the cheeks where they are completely out of the way of the tongue.  Studies have shown that anything which affects tongue posture similarly affects jaw posture.  When a block of acrylic was cemented in the palates of growing monkeys, they developed long narrow retrusive faces, because the tongue pulled back to avoid the acrylic and thereby pulled the lower jawbone back too.  In the same way, simple appliances which employ a palate full of acrylic or a thick ramp behind the upper front teeth also cause some lower jawbone retrusion by producing a retrusive influence on the tongue.  
 
BITE STABILITY
Another important aspect of orthopedic treatment of the TMJs involves ensuring adequate long term stability of the natural bite.  Stable bites are a fundamental requirement for long term TMJ health.  All the body’s joints maintain a perfect fit between the opposing bones, because functional forces trigger cellular activity which continuously remodels bone contours until pressure is perfectly distributed between them at rest and during function.  For the lower jawbone, functional movements and even the resting position are controlled by the natural bite.  Therefore, for the TMJs to acquire a perfect fit between the opposing bones, the natural bite must provide a consistent and centrally located bracing position for the lower jawbone as well as smooth consistent chewing pathways for the lower jawbone  in and out of that bracing position.   If the bite keeps shifting even slightly, the bony contours of the TMJs must be constantly altering their shapes by remodeling to fit a moving target.   
 
In many people with TMJ disorders, the bite has been destabilized by either the dislocation of the disk or the ongoing degeneration in a TMJ producing a loss of height in one or both of the condyles at the back ends of the lower jawbone.  This loss of condyle height causes a small change in the angle or cant of the lower jawbone.  As a result of even a minute change in the angle of the long lower jawbone, the teeth no longer fit together correctly.
The unstable bite then tends to maintain itself.  Without a clear central place for the lower jawbone to call “home”, the lower jawbone squeezes closed in a variety of positions, so the teeth are prevented from developing one clear central bracing location.  The frequent shifting of the bracing positions for the lower jawbone then makes it difficult for the TMJ to heal properly, which perpetuates the bite instability.
 
PIVOTING
When only one of the TMJs has an arthritic condition, rapid short-term relief can be produced by adding a pivot at the rearmost section of the affected side of an oral appliance, a denture, or the natural teeth.  The pivot is a high spot which hits slightly before the other teeth.  The leverage produces a slight prying down of the back end of the lower jawbone (the condyle) in the TMJ on the side of the pivot.  Such direct mechanical distraction relieves compressive forces and allows increased circulation into the injured TMJ.  Pain relief should be almost immediate, especially during biting. 
 
Pivoting is a temporary measure, because pivots eventually wear down or cause intrusion of the two affected teeth..    Thus pivoting must be considered a short term solution for an acute problem rather than a long term strategy.
 
SUPPORTIVE TREATMENTS
After the damaged TMJ has adapted fully and the inflammation is gone, some of the symptoms may persist due to "muscle memory" or other neuro-anatomical changes caused by long term dysfunction.  In such cases, there are a large number of supportive treatments that can help eliminate the symptoms   These treatments include exercises, stretches, postural work, jaw muscle retraining, a variety of drugs, psychological counseling, biofeedback, and various relaxation strategies.
 
Strengthening exercises are especially important in people with relatively weak jaw muscles. Facial growth continues at a slow rate throughout adulthood.  During this continual facial growth, the jaw muscles are responsible for maintaining harmony among the diverse growth systems which control the many different bones in the face. Thus the jaw muscles and the neck muscles need sufficient strength to properly regulate facial growth.
 
If muscles are to stay healthy while they become strong, strengthening must be balanced with stretching.  Stretching of the jaw muscles can be accomplished by using a tall and stable bite surface to grind or clench against during sleep.  Such a bite surface can be provided by a simple stabilization appliance or a telescopic appliance.  The amount of stretching can be varied by changing the height of the appliance.  Many people cannot start with much height, but can tolerate increased height and thereby gain better stretching as treatment proceeds and the pain disappears.
 
Stretching of the jaw and neck muscles can also be accomplished by using ice in conjunction with mechanical stretching.  While an ice pack (or a bag of frozen peas or corn) is held against the side of the face, the jaw muscles are mechanically stretched by holding a wine cork,a piece of wood, or a rolled up cloth between the front teeth so the mouth is propped fairly wide open.  This combination of cold and stretch is held for about 5 to 10 minutes.  Then the block and the cold are removed, the jaw is allowed to close, and heat (a hot wet towel) is applied where the ice was.  The heat should feel good after the ice, and it brings in new blood to replenish what was flushed out by the ice and stretch technique.  The neck muscles can be mechanically stretched by holding the head tipped or twisted to one side while ice is applied on the opposite side.
 
The resting posture of the jaw and neck muscles is also affected by attitude.  Just as people jut the lower jawbone when they feel angry or determined, they retrude the lower jawbone when they feel defeated or sad.  The frequently use of a retrusive jaw position can aggravate the tissue damage which is usually located at the back of the TMJ.  The ongoing TMJ tissue damage and the resulting chronic pain cause feelings of sadness or defeat (depression), which then produce more jaw retrusion, so another vicious cycle ensues.  Because of this mutually supporting relationship between TMJ problems and depression, coupling some psychological counseling with TMJ treatment is a good way to make them both more effective.  We work with a professional counselor to reinforce the improvement of jaw posture with changes in attitude that are associated with an improvement of jaw posture.