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Dental problems from scuba regulator
bites
by Laurence Stein, DDS
Diving Medicine Online Dental Consultant
PADI Divemaster D-35892
DAN Referral Physician Team (2000)

Question:  I was doing multiple dives over more than a week and now I have limitation of jaw opening and pain in my jaw joints.  What happened?

Answer:  This is a potential "can of worms".  There may be multiple reasons for this to happen.  I will try to simplify some of this information but for other dental professionals, they will note some inconsistencies in the answers.

In order to come up with a reasonable answer to this question, there are a number of dental and medical conditions that must be considered.  External and middle ear infections, internal derangement of the articular disc within the jaw joint (temperomandibular joint), Tempero Mandibular Joint Dysfunction Syndrome (TMJ) or Tempero Mandibular Dysfunction (TMD), bruxism and clenching, unerupted wisdom teeth, infections within the maxillary sinuses, pericoronitis (infection around or over an unerupted or partially erupted tooth, periodontal infection and abscessed teeth.

Diagrams and Illustrations of the TM Joint
This web site contains some very good diagrams of the TM joint.

Each one of the above listed conditions has the potential to create some or all the symptoms you described.

Why would there be limitation upon opening of my jaw?

Answer:  There are multiple possibilities.  Probably the easiest explanation for limitation of opening is something called a "closed lock".  This is a type of dislocation of the head of the mandibular condyle (the ball) relative to the fossa (socket) of the joint.  If the jaw joint pops or clicks, this is a sign that the condyle is popping onto and off of the disc.  The may cause permanent damage.  However, there are persons with clicking all their lives and have never had treatment.

The tempero mandibular joint is probably most complex joint in the body.  It is made of upper and lower halves separated by an articular disc.  To complicate this, while each side of the jaw has a joint, they both must move in harmony with each other for proper function to occur.  Movement of one side must cause some movement on the other side.  While pain or movement limitation may only result from dysfunction on one side, the opposite side must also move and in some ways compensate for the dysfunction on the other side.

A closed lock occurs when the disc between the upper and lower halves somehow manages to slip in front of the condyle and fossa during movement.  This is called an anteriorly displaced disc.  When this occurs, the disc may fold up or crumple up and prevent further forward movement of the affected side.  The effect is like putting a rubber doorstop under a door so it can't move.  In this case, the doorstop prevents opening.  This limits the jaw opening.  This condition may spontaneously reduce or continue to be a problem and require (usually conservative) treatment to "capture" the disc back on top of the condyle and fossa.

Old sports injuries to the jaw or other trauma may have damaged the joint and predispose it to dislocation.  It is NOT necessary that the actual trauma involve striking the lower jaw.  Trauma from the momentum of the lower jaw may be sufficient to create such an injury. Therefore a lack of trauma to the lower jaw does not mean a joint injury may not have occurred.

With an anterior displaced disc, occasionally, the condyle (ball) is displaced toward the back of the joint onto highly innervated, vascular tissues that are very sensitive to pain.

Can ear infection cause these types of problems?  Yes, while there may be no disc displacement, the external ear canal and the middle ear overly the jaw joint. Multi-day, multi dives may lead to ear infections, which, while they are located in the ears, their proximity to the jaw joints may cause joint pains and dysfunction. Swelling due to infection or inflammation can put pressure on the joint and result in both pain upon opening the jaw and limitation in the amount of movement.  Having the ears examined by your ENT is quick and can eliminate this as a cause.

How about infections within the mouth?  These can also cause limitation of opening due to "guarding".  This is a muscular response to an injury to attempts to brace the muscles in such a way that further injury is lessened.  Unfortunately, this guarding or muscle trismus is painful.  Trismus is commonly seen in infected, unerupted or partially erupted wisdom teeth.  This condition is called a pericoronitis if it affects the gums overlying the wisdom teeth or in some cases, the gums on the back sides of the second molars, if they just barely have enough room to come into the mouth.  The removal of some but not all wisdom teeth may also create a problem if one of two teeth is removed from each side and the remaining tooth is able to supererupt into the mouth.  The super erupted (over erupted) tooth may bite the opposing gums or cheek causing infection and/or pain and limitation to opening.

Maxillary sinus infections and inflammation can lead to joint problems too.  The upper molar and bicuspid teeth typically are located along the lower border of the maxillary sinus.  Any swelling within this space can put pressure on the underlying teeth and press them into the mouth very slightly.  Once your "bite" has sensed this change, you will start to clench on the "premature contact" created by the tooth or teeth being displaced downward into the mouth.

I clench my teeth-especially at night.  Does this cause problems?

The short answer is yes it may.  Clenching or bruxing has been implicated in muscle spasms and headaches (stress and migraine types).  People who clench heavily at night during sleeping are at greater risk for both headaches and TMJ or TMD syndromes.  TMJ or TMD are, for practical matters a muscular condition involving the spasm and then the lack of harmony of both sides of the jaw to work in unison.  The constant forces on the joints are created by abnormally strong contractions of the muscles of mastication-especially the Temporalis Muscle.  Also affected may be the Masseter Muscle and the Internal Pterygoid muscle.  This last muscle, although small, may go into spasm and become very painful.  This muscle is responsible for moving the jaw side to side.  If one side becomes sore, the other Internal Pterygoid muscle will start to pull the jaw away from the fatigued side.  Since it is a small muscle, it will fatigue relatively quickly.

The Pterygoid muscles (Internal and Lateral) also are responsible for positioning the articular disc within the joint.  When these muscles become fatigued and spastic, the disc fails to move with the condyle (ball), staying on top of it while it traverses the fossa (socket).  This socket is "S" shaped and allows both hinge movement and translational movement-side to side and front to back.

The jaw movements, disc movements and tooth position must all be choreographed, precisely for the joint to work properly.

Constant pressure on the joint and muscle contraction to hold a regulator in the mouth may cause problems-especially if there is an underlying weakness already present

It is important to understand that since all the muscles operating the jaws must work in harmony with each other and each side.  Once any particular muscle begins to fatigue or spasm, the other muscles will try to compensate.  Compensation can be though of as additional contraction or work and the result may be fatigue and spasm of other muscles.  The net result may be a cascade of fatigued muscles leading to joint dysfunction

Clenching and bruxing can also result in premature wear of teeth, sensitive teeth and fractured cusps or teeth. In many of the cases, the wear is NOT on top of the tooth but on the sides next to the gums.  These wear areas are called abfractions.  These wear areas get deeper with time and can cause sensitivity, and compromise the nerve within the tooth.  Also seen in heavy clenchers, is the deposit of bone on the inside of the lower jaw near the bicuspid and canine teeth.  These are called tori.  A torus (singular) or tori (plural) may also occur in the midline of the upper palate.  It may appear as a single bump, an elongated bony ridge or a four lobed, cauliflower appearing, bony hard swelling.  The reason for the tori is to reinforce the bone that is flexing as a result of clenching.  It is a reactive process by the body to counteract the flexure of the bones due to excessive mechanical stress.
Occasionally, a bony ridge may appear in the gums around the necks of teeth--especially the molars and bicuspids.  When present, it is usually on the cheek side of the teeth but can be found on the lingual (tongue or palatal) side as well.  This is a reactive process to the movement of the teeth within the bone.  The body is trying to brace or reinforce the teeth to keep them from moving.

Signs of nighttime bruxing are tired or sore jaws in the morning.  Limitation of opening movement, difficulty keeping the mouth open for even short periods of time without fatigue and spontaneous closing of the mouth.  You spouse may tell you that you were making terrible noises at night with your teeth while you were sleeping-you cannot reproduce these noises awake.  The sound is kind of glass rubbing on glass and it "creeps you out" when you hear it-like fingernails on a blackboard.

Is there a cure for TMJ?  Yes and no. TMJ is a very complicated condition.  It is sometime not possible to tell if stress or a bad bite causes the muscle spasm. Clenching and bruxing due to physical or emotional stress creates the conditions necessary for the muscles to spasm, leading to a change in the bite and then predisposing to further problems.  Conversely, a bad bite may lead to constant stress on the muscles and then spasm.  Kind of a chicken and egg problem...

TMJ/TMD should be treated very conservatively. Try to use non-invasive, reversible modalities such as bite splint therapy, muscle relaxants, antianxiety medications, and anti-inflammatory medications. On rare occasion, a bite adjustment of the nature teeth may be needed to remove a gross prematurity.  Surgery is indicated in less than 1% of all TMJ episodes.  Never use it as a treatment of first choice.  The same is true for expensive x-ray exams.  While they can be helpful in some cases, their costs are more than offset by conservative therapy that seems to be working.  Leave the surgery and radiologic exams for refractory cases.  In the absence of pain, treatment of joint sounds and deviations of movement is not usually recommended.

If you have been diagnosed with TMJ please note that it may recur intermittently.

Common TMJ symptoms are:
- Headaches
- Pain behind the eyes
- Dizziness
- Earaches or ringing of the ears
- Clenching or grinding of the teeth
- Neck, shoulder, or back pain
- Numbness, or tingling of the fingers

Generally, it is agreed that a poor bite will predispose to TMJ as well as "premature contacts-especially on the side surfaces of the back teeth.  Certain occlusal schemes may also predispose to the condition.  The inability to "ride" on the back sides of the upper front teeth with the lower front teeth (anterior disclusion) will contribute to severe wear of the back teeth and possible TMJ.
This is easily seen in a patient who has a severe under bite.  The lower teeth stick out way beyond the upper teeth.  As a result, the only teeth that can touch in any movements are the back teeth.

There are two reflex movements in the mouth depending on which teeth touch.  If the back teeth touch food, a message is sent to the brain to CRUSH that food.  So you will bite harder.  An opposite reflex signal is sent when only front teeth touch.  This is called nocioceptive inhibition.  In this case, both temporalis muscles fail to contract or only slightly.  These are the muscles associated with bruxism and are the largest and most powerful of the biting muscles.  In an ideal bite, you want the front teeth to begin to separate the back teeth as soon as any forward or sideways movement begins to occur, shutting off the need to clench really hard.

You can also do an interesting experiment to see how these reflexes work.  Put your fingertips to your temple on each side of you head-above the ear and behind the eyes.  Clench you molar or back teeth together.  What did you feel?  You should have noticed the muscle tense up in that area.  This is the Temporalis Muscle, the largest and most powerful muscle used to close the mouth.  Now, jut your jaw forward just enough so that only the upper and lower front teeth touch and bite the front teeth together as hard as you want.  Feel the muscle- as you do this nothing happens!  The brain's sensing of front tooth contact has shut off the contraction of the Temporalis muscles.

There is a growing body of evidence that suggests that people who clench, especially during sleep are more prone to both tension and migraine headaches.  The constant fatigue created by the clenching sort of "overloads" the Trigeminal Nerve root.  This nerve also innervates some of the vasculature and covering of the brain.  What happens next is still speculative, but if the Trigeminal Nerve ganglion starts to spontaneously "fire", you can then get vascular changes in the brain and a migraine starts.  It's sort of like a mini seizure and that is why some migraine patients are treated with anti-seizure medications.

Remember the cascade effect I mentioned before?  In addition to cascading muscle contractions of both jaw joints, there can also be a cascade of muscle spasms starting at the head and then moving down the neck and back.  Once one muscle begins to fail at its job, others try to compensate and begin to fatigue and fail.  Finally, everything can begin to hurt-sore jaws, sore head, sore neck, and sore back.

Finally, why do you say that the regulator bite causes bite problems?

The normal regulator bite tabs are located on the bicuspid and molar teeth.  In this position, they actually stimulate the jaw to bite harder.  The more fatigued you become, the harder you bite.  This can precipitate a TMJ episode.

An ideal regulator bite would have only the front teeth touch.  Unfortunately, it is difficult to impossible to create this type of device without compromising airflow.  A custom bite is next--allowing a more even distribution of forces on the teeth.  Its drawback is that since the back teeth are touching, you will still clench.  Another drawback is that few people are capable of properly setting the proper "hinge axis" on the custom bite to match the proper fit of the jaw joints. Finally, the U.S. Divers ComfoBite mouthpiece may be useful because it "floats in the mouth-requiring little or no biting to hold it in the mouth.

Treatment for internal derangements and symptomatic TMJ is by the use of anti-inflammatory medications such as Ibuprofen, Naproxsen, Rofecoxib, and even aspirin.  Care to avoid these drugs in the presence of aspirin allergy, aspirin related asthma, allergy to sulfonamindes, and gastric bleeding should be noted.

Moist heat to the affected joint may be useful.  A soft diet, No chewing gum, Care not to bite big sandwiches or wide yawns, don't sleep on the side of your face. A bite guard or splint therapy may be necessary.  Occasionally, muscle relaxants, minor tranquilizers, and even anti-depressants may be used.  Isometric exercises can be used as well.

In the event you do have the above signs and symptoms, see you doctor and/or dentist first to rule out infections of the ears, sinuses, teeth and gums.

So, what started out as a discussion of sore jaws and diving turns into a complicated story about muscles, joints, discs, spasms and headaches.  Can a regulator cause jaw pain or limitation of opening?  Yes.  Lots of things can do this and most of the time the predisposing factors are more important than the regulator mouthpiece.

Related links:

Temporomandibular Disorders - TMJ/TMD...A Discussion About Diagnosis and Treatment.
http://www.drsidholleman.com/

Dental Compression Syndromes
http://www.toothcrunch.com/

Tempero Mandibular Diseases
http://www.nidcr.nih.gov/health/pubs/tmd/main.htm

Temporomandibular Joint Disorders
The University of Texas Medical Branch
http://www.utmb.edu/otoref/Grnds/tmj-1998/tmj.htm

Internal Derangements of the Temporomandibular Joint: The Role of Arthroscopic Surgery and Arthrocentesis
http://www.cda-adc.ca/jcda/vol-66/issue-4/199.html
 


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