What Happens When You Grind?

 
           Bruxism (grinding your teeth) is known as a parafunctional habit. Another parafunctional habit is clenching. These are activities related to, but not part of, the main function of your teeth. Your teeth's primary operation is chewing. Both of these habits are considered to be stress connected (in all its forms) and both can be harmful to your teeth, temperomandibular joints (TMJs) and gums. Your TMJs are the jaw joints located just in front of your ears that you can feel moving with your fingers when you open and close your mouth. Bruxism usually takes place during sleep while clenching may occur at any time. Flattened out areas on the chewing surfaces of your teeth, known as wear facets, are often the initial indicators of these parafunctional habits.

           The stressors that can cause you to grind or clench your teeth are many and varied. Emotional stress, malocclusion (bite discrepancies), intense physical activity and environmental stress are among the factors that can induce these parafunctional habits. Some of the many problems that bruxism and clenching can contribute to include; tooth wear, tooth fracture, periodontal disease, cervical abfraction and temperomandibular dysfunction (TMD).

 

The flattened out tip of this tooth explains its cervical abfraction (arrow).



           Probably the most talked about issue related to these parafunctional habits is temperomandibular dysfunction (TMD). TMD is often called TMJ by the public even though the latter stands for temperomandibular joints, which everyone has. TMD refers to the group of syndromes associated with pathological changes in and around the TMJ. The following are some of the signs and symptoms that characterize TMD; the inability to open your mouth fully, clicking or popping sounds when you open and close, locking of your jaws in either the open or closed position, pain when you open and close, pain when you chew, headaches (particularly at your temples), facial pain that may radiate to your ears and pain in your jaw muscles. These signs and symptoms may arise from inside your joints themselves or from the muscles and ligaments surrounding them. Blunt force trauma, such as may occur in an automobile accident, and arthritis are some of the other causes (besides parafunction) of TMD.

           Grinding and clenching your teeth can severely wear or even break them. In extreme cases, I have seen people who have bruxed past the outer layer (enamel) of their teeth, then through the middle layer (dentin) and into the nerves! This condition necessitated root canal treatment. In another instance, I have a patient who grinds his teeth so violently in his sleep that he once fractured one of his teeth off at the gumline waking both himself and his wife with a start.

 

Grinding can cause wear and chipping like this.



           Parafunction can also cause problems with the supporting structures (gum tissue and jaw bone) of your teeth called periodontal disease. This may also extend to the neck area of the teeth (known as the cervical) in a condition termed cervical abfraction. Just as hurricane winds will uproot a tree, so can bruxism recede the gums and erode the bone that support the roots of your teeth. Clenching causes attrition of the teeth at the gumline that is cervical abfraction in much the same way as heavy traffic on a bridge may cause cracks in the concrete at the bases of columns supporting it.

           Many of the problems mentioned previously can be helped by wearing a simple dental appliance called a nightguard or bite splint. As the first name implies, it is worn while sleeping and somewhat resembles the athletic protectors worn by players during sports. It differs from these devices in that a nightguard is custom fitted for your teeth and bite by means of an impression (mold) being taken of your teeth and the bite being adjusted to yours when the appliance is delivered. Its purpose is to prevent parafunction during sleep (when it most often occurs) by preventing contact between opposing teeth. In cases of uncontrollable clenching during the day, the nightguard may need to be worn while awake, but this is rare. A nightguard can be made of soft acrylic, but in most situations and especially with extreme grinding and clenching, it will be made of the hard type to prevent splitting and increase the lifespan of the appliance.  Also, in many cases where a bite discrepancy is at the root of your grinding, a selective adjustment to your bite (called harmonizing or equilibration) can relieve its cause and may even allow you to go without a splint. 

           A nightguard, however, can only prevent the damage of parafunction to hard tissues from occurring before it happens. In some cases where the damaged has already happened, such as tooth fracture or cervical abfraction, other treatments may be needed before the nightguard can be inserted to prevent recurrence. Examples would be crowning a fractured tooth or repairing cervical abfraction with bonded fillings. In the case of TMD, nightguard placement can often correct those parafunctional changes that have occurred in the soft tissues in and around the joint (muscle spasm, ligament strain or cartilage displacement), but bony changes within the joint may require surgery. I always take a special x-ray (called a panorex) to assess your joints for these changes before prescribing treatment. If bony changes are evident, I will refer you to a specialist for appropriate treatment. In the case of malocclusion, referral to an orthodontist to realign your bite may be needed. If a malocclusion has caused bony changes in your joints, orthodontic treatment may need to be followed by surgical repair of your joints by an oral surgeon.

           As with all health related matters, PREVENTION IS THE KEY. Treating parafunctional conditions before they become significant problems is the best way to avoid major troubles in the future. When obvious wear facets present on many of your teeth, splint therapy and equilibration should be considered to head off the above mentioned conditions before they become larger issues for you. If you have any questions about any of these points, please ask me.

 




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Dr. Barry F. McArdle, D.M.D. ~ 118 Maplewood Avenue, The Captain Moses House, Suite B-7, Portsmouth, NH 03801

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