Bruxism is excessive clenching or grinding of the teeth that is not a normal part of chewing movements and is associated with excessive jaw muscle activity. It occurs in most humans from time to time and is mild enough not to be a health problem. While it may occur during the day, it is during sleep that causes the majority of health issues.
Bruxism is a habit that is controlled by subconscious or conscious brain activity. During sleep, subconscious brain processes can run unchecked, allowing bruxism to occur.
The trigger for bruxism can vary from allergic reactions, some medical conditions, motor vehicle trauma, to a period of unusual stress, but once bruxism becomes a habit, the original stimulus can be removed without ending the habit.Signs
Most people are not aware of their bruxism. Bruxism may be loud enough to wake a sleeping partner and it is often a sleeping partner that notices the behaviour first, although the sufferer may notice pain symptoms without understanding the cause. Only an estimated 5% go on to develop symptoms such as jaw pain and headaches.
Bruxism can result in abnormal wear patterns on the biting surfaces of teeth and fractures and cracks of teeth. Over time, dental damage increases.
Some patients grind their front teeth with a side-to-side action (using the medial pterygoid muscles), leading to a shortening of the front teeth affecting the smile and speech. Other patients grind their back teeth (using the masseter and temporalis muscles), flattening down the cusps and wearing through the enamel. Once the enamel is lost from the biting surface of molars, the softer dentine will wear faster, leading to hollowing (cupping) of the tooth surface. These teeth tend to be sensitive, especially to acid or citrus foods.
Many patients work their jaw muscles (grind their teeth) to improve their concentration, esp those engaged in sports. This is very common amongst students at exam times, during marriage and divorce, buying a house etc. Clenching and grinding may occur during the day, where it may be brought to the patient’s conscious awareness; or at night, where a patient may wake with a sore jaw area and/or break a tooth at breakfast.
Patients may present with a ariety of symptoms including:
Anxiety, stress and tension; depression; earache; eating disorders; headaches; migraines; loose teeth; worn teeth; tinnitus; gum recession; neck pain; insomnia; sore and painful jaw.
The following may be associated with bruxism (whether by cause of effect):
- Disturbed sleep patterns (as well as obstructive sleep apnea, hypopnea, snoring, moderate daytime sleepiness)
- Malocclusion, in which the teeth bite in a disharmonic way, eg through premature contact of back teeth)
- Relatively high consumption of caffeinated drinks and foods, eg coffee, cola
- High levels of alcohol
- High levels of stress, work –related stress, irregular shifts
- Drug use, esp stimulants, including these taken for medical reasons
- Obsessive-compulsive disorder
Bruxism is not the only cause of tooth wear, making it difficult to diagnose by visual evidence alone.
The most reliable diagnostic technique is the measuring of muscle activity by EMG (electromyography). This is commonly used in sleep labs. Adhesive electrode/sensors are attached to the user’s face either directly or with the aid of a headband.
If diagnosed early, finding and eliminating the original cause(s) may cure bruxism. Treating associated factors can reduce or eliminate the behaviour in cases where bruxism has not become habitual.
Later on, habitual bruxism can be treated by habit modification.
A dental guard or splint, made of hard plastic to fit over the upper or lower teeth, can reduce tooth abrasion and reduce muscle strain, by allowing the jaws to move easily with respect to each other. A dental guard is typically worn during every night’s sleep on a lng-term basis. Dental guards to do not cure the condition.
The are several proprietry design aplliances promoted in the popular press. The use of repositioning splints (designed to change the patients’s bite, or NTI-tss (nociceptive trigeminal inhibitor) can have uncertain results and are potential very harmful.
Contingent electrical stimulation involves combining electromyographic monitoring of jaw muscle activity with electrical stimulation of the skin to trigger an inhibitory reflex in the brain that relaxes the jaw muscles and inhibits bruxing.
Other treatments include use of a biofeedback device, botox injections to reduced muscle strength, and dietary supplements such as pantothenic acid, magnesium and calcium.
Repairing damage to the teeth and bite may be required. This may be as simple as minor reshaping of some teeth to remove occlusal interferences; or major reshaping using the full range of restorative methods available today.
DR. MALCOLM J. GRENNESS
B.D.Sc., L.D.S., M.Med.Sc., PhD, F.R.A.C.D.S
Call: (03) 6224 3575
158 Collins Street, Hobart
Monday – Friday 8.45am-5.15pm
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