When bite strain is suspected as the ultimate cause of the TMJ disorder, identifying and subsequently eliminating bite strain can bring about a permanent relief of symptoms.  Eliminating bite strain requires locating the ideal unstrained bracing position for the lower jawbone to compare with your current natural bracing position for the lower jawbone (the position of full dental interdigitation).  Locating the ideal unstrained bracing position for the lower jawbone requires deprogramming the jaw muscles with a flat bite plate appliance so the  jaw muscles can demonstrate their preferred closing trajectory, bracing position, and exercise range of motion.   

 

The front flat bite plate appliance deprograms the jaw muscles by providing a bite surface which is so flat and smooth that the lower jawbone can freely glide around in all directions. No matter what trajectory the lower jawbone uses during closing, it strikes an even flat stable bite surface all night long.  As a result, the jaw muscles stop getting signals to bring the lower jawbone to the precise location where the teeth fit.  The jaw muscles can exercise the lower jawbone in any position that feels natural and comfortable for them.  In the morning, after the jaw muscles have been deprogrammed in this fashion, we can see the lower jawbone position which is most comfortable for the jaw muscles.

 

The length of time needed to deprogram the jaw muscles depends on the health of those muscles.  Children and young people with healthy jaw muscles often deprogram overnight.  They may even have trouble finding the old strained bite in the morning after removing the flat plate appliance, because the deprogrammed jaw muscles have become used to operating in the new more comfortable jaw position, and they can hold that position for some time in spite of the teeth not fitting there.  The average adult TMJ disorder patient requires days or weeks to deprogram.  Some patients with longstanding TMJ disorders characterized by weakened unhealthy jaw muscles may also require exercises, stretches, and massage to help rehabilitate the jaw muscles before they can fully deprogram and demonstrate the optimal lower jawbone position for exercising and bracing. 

 

EVALUATING YOUR BITE

When you wake up with your jaw muscles deprogrammed and you remove the appliance so your lower jawbone can swing closed naturally, at the top of that swing should be the full interdigitation of all of your back teeth.  If you notice one tooth striking before other teeth every morning after you remove the appliance, that tooth may constitute what is known as a bite interference.  The bite interference may be located on a front tooth, a canine, or a back tooth.   If you squeeze your lower jawbone closed against a bite interference, it will be driven back or to one side until it returns all the way to your current strained bite position.

 

IMPROVING YOUR  BITE

There are a number of ways to eliminate bite interferences and restore a healthy bite.   High spots can be drilled down, or low spots can be built up. Frequently the two techniques are combined.  When crowns or onlays are needed anyway for structural support of weakened teeth, those crowns or onlays are an excellent means for improving a bite.

 

Drilling down high spots involves locating bite interferences and then reducing them with a high speed drill in a process known as equilibration.  The process doesn’t harm teeth or make them more susceptible to developing cavities, because cavities only form where food gets trapped.  Until MRI became popular and made us realize that the vast majority of TMJ disorder patients have a dislocated TMJ disk, equilibration was the primary means used by dentists to treat TMJ problems, and the largest TMJ professional organization in the world is still the American Equilibration Society.  Equilibration is especially useful in people with excessive face height or steeply interdigitating tooth inclines which restrict the range of motion of the lower jawbone.

 

Building up low spots is preferred when face height is already very short or when there is evidence that any further shortening of the face is likely to cause symptoms.  Building up teeth is especially advantageous when the teeth already have fillings, because it can significantly reinforce those weakened teeth.

 

The simplest and most inexpensive way to add structure to the tops of teeth is with tooth colored composite resin filling material.  This material bonds to enamel with incredible strength, it can be carefully matched to the color of the tooth, and it can be easily ground down or added to itself in later adjustments. The primary disadvantage of using composite resin for building up teeth is that the material tends to wear down.  Teeth were designed to wear down slowly and steadily, so in most people the wear of composite resin is not a problem.  However, in people who have strong jaws and vigorous tooth grinding habits, wear of the composite resin may occur rapidly enough to destabilize the bite, so more longlasting materials like gold or porcelain onlays or crowns may be required – especially on the molars which receive most of the bite force.  

 

Teeth that are structurally compromised, (like those with old silver/mercury/tin amalgam fillings),  will require gold or porcelain onlays or crowns eventually anyway, so they can be restored as part of the process which recreates a healthy bite.   The silver/mercury/tin amalgam filling material fills the hole in the middle of the tooth so food won’t collect there, and its corrosion products inhibit bacterial growth, but the amalgam filling does nothing to reinforce the tooth structurally.  The amalgam doesn’t bond to the tooth at all, so structurally the tooth becomes a shell with a plug in its center.  In addition, because the amalgam plug is made of metal, it expands and contracts with temperature changes more than tooth structure does, so it starts leaking on day one.  Eventually, as the tooth becomes more brittle with age, the tooth usually chips or cracks from around the filling. Amalgam fillings last an average of 17 years and often last for 30 years, but they rarely last a lifetime.  At some point they will need to be replaced by a solid piece of gold or porcelain such as a crown or onlay which covers the entire top of the tooth so that no part of the tooth structure below can fracture. An onlay is a tooth top which is bonded to the tooth structure below.  Onlays require much less drilling and thereby diminish the chances of a tooth requiring a root canal later.  If several teeth need to be restored, the bite can be improved in the process.  In contrast, when a person gets one crown or onlay at a time, it is almost always made to fit whatever bite you have at that time, whether it is strained or not.  

 

Gold is the ideal material for reconstructing bite surfaces.  It is extremely accurate and biocompatible.  It has a hardness very similar to natural tooth structure – which minimizes wear.   In addition gold is strong even when thin, and it can be bonded to enamel with impressive strength.   

 

Porcelain has excellent esthetics, however it also has disadvantages.  Porcelain needs bulk for strength, so the preparation process requires significant tooth reduction.  It’s also difficult to create an accurate bite with porcelain, because porcelain cannot be simply cast to fit the bite but must be initially built too high and then ground down until it is no longer too high.  Finally, porcelain is so much harder than natural teeth that it can wear away the opposing natural teeth and make them sensitive.

 

The front flat plate appliance can also use your nocturnal clenching and grinding forces to gradually reduce the overbite of the front teeth.  The vertical overlap of the front teeth, known as overbite, is a major cause of inhibited forward growth of the lower jawbone and dislocation of the TMJ disk during adulthood.  The overbite creates a wall of tooth structure in front of the lower jawbone.  That wall can be a barrier to normal facial growth which continues to bring the lower jawbone forward relative to the upper jawbone throughout life.  This normal growth causes a slight flattening of the profile with age.  However, a retained steep overbite can redirect that growth vertically.  Reducing that steep overbite gradually over time can restore a healthier facial growth pattern and thereby greatly reduce the chances of developing TMJ disorders later in life.

 

The front flat plate appliance reduces overbite by using the forces of nocturnal bruxism (clenching and grinding) to push upward on the upper front teeth and downward on the lower front teeth.  In this way the upper and lower front teeth are pushed vertically away from each other while the back teeth are relieved from all bite forces and allowed to get taller by erupting further.    As a result, the vertical overlap (overbite) of the front teeth is reduced.  If the front flat appliance is worn nearly full time, overbite will be reduced relatively quickly, at a rate of about 2-3 mm per year.  If the front flat plate appliance is worn only at night, overbite will be reduced much more slowly, at the rate of about ½ mm per year.   The overbite will keep reducing only until the back teeth start to make contact in the appliance.  Thus the target bite platesreduction in overbite can be controlled by adjusting the height of the back portion of the appliance.

 

Another very specific effect of wearing a front flat bite appliance is reducing, by at least half, the amount of force used in nocturnal grinding and clenching.  Everyone clenches or grinds the teeth during sleep, and everyone does it more when they are under stress.  Most people are not aware of their nocturnal grinding and clenching, because it occurs mostly during transitions between sleep stages.  The front flat bite plate may not change the frequency or duration of this clenching or grinding, but it reduces the amount of force used.  The jaw closing muscles are simply unable to shower down their big forces if they don't get the proprioceptive "go ahead" from multiple stable contacts  between the back teeth.  Even anesthetizing the back teeth limits the closing forces which can be applied to the jaws.

 

Because nocturnal clenching and grinding are a common cause of headaches, flat front  bite plate appliances are often effective in treating headaches.   The jaw muscles are capable of applying powerful forces to the head.  In monkeys biting has been shown able to bend the head and slightly open the parietal suture running along the top of the head.  Thus, if the forces used during nocturnal clenching and grinding are the cause of your headaches or other symptoms, the front flat bite plate may be an easy way to eliminate those symptoms.  

 

The front flat bite plate is effective in treating jaw muscle tightness, but it is not effective in treating TMJ inflammation.   If the flat front bite plate appliance does not relieve your symptoms, those symptoms are more likely being produced by your TMJs than your jaw muscles.  In such cases, we can convert your front flat bite plate appliance to a stabilization appliance in one appointment using our in-house lab.  You'll bring in the front flat plate appliance and leave an hour later with a stabilizaton appliance.

 

COSTS

The front flat plate appliance costs $750.   Converting it to a stabilization appliance, if necessary, costs another $200.  The costs involved in changing or stabilizing a bite just depends on the amount of chairside time involved.  Adjusting teeth by grinding down low spots and building up high spots usually costs anywhere from $100 to $900.  Completely altering the bite by rebuilding it  with composite resin usually costs anywhere from $600 to $1800.  If there are several teeth that already have decay or old fillings, those teeth will eventually need structural reinforcement.  They can be built up on a temporary basis with composite resin, but they will eventually need to be reinforced with crowns or onlays made of gold or porcelain to eliminate the chance that a bite force could cause them to fracture with age as the teeth dry out and become more brittle.  Onlays cost  $850 per tooth, and crowns cost  $975 per tooth.

 

After a bite is altered by permanent build-ups, whatever oral appliance you wear at night will need to be adjusted so that it will fit over the new tooth contours.  The appliance can easily be relined, resurfaced, or otherwise altered at chairside.  The costs for adjusting your appliance to fit a new filling or crown are usually $50 to $100.