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INDIAN DENTAL ACADEMY Leader in continuing dental education


Historical perspective : gnashing of teeth has been described in Bible. (Psalm 35:16,Psalm 112:10,Job 16:9). Bruxomania – recorded in literature early in twentieth century. In 1931, dysfunctional mandibular movements were described as bruxism, term mania was removed, because the mandibular bruxist behavior could not be related to psychopathology.

DEFINITION General – Forcible clenching or grinding of the dentition or a combination of both. American Academy of Orofacial Pain – Diurnal or nocturnal parafunctional activity including clenching,bracing,gnashing and grinding of teeth. American Sleep Disorders Association – Tooth grinding or clenching during sleep plus one of the following : tooth wear, sounds or jaw muscle discomfort in absence of medical disorder.


Highest in age group teen to forties. Females > Males. Self reporting during waking hrs – 20%. During sleeping hrs – 10%. Determination of actual prevalence is difficult because this mandibular parafunctional behavior is performed at a subconscious level by most individuals.

ETIOLOGY Cause is multifactorial and overlapping. Creates difficulty for the practitioner in applying a comprehensive ,effective management plan for this mandibular parafunctional behavior. 1) Occlusal interferences – Assumption was that the patient was making a subconscious attempt at performing a self equilibration or adjustment of his or her dentition to remove the occlusal interference. Not supported by more recent investigations.

2) Periods of emotional or physical stress – during times of concentration or strenuous activities throughout the day, individuals often occlude their teeth with a concomitant application of force. 3) Sleep disorders. 4) Consumption of alcohol – aggravates it. 5) Disturbances of CNS. 6) Psychiatric medications

Why bruxism is a problem? It has been stated that of all the functional disorders of the dentition,bruxism is most destructive. Over time the complications of bruxism may cause permanent damage to the teeth and uncomfortable oral and facial pain. During sleep the force of bruxing can be up to six times greater than normal waking biting pressure, approximately 250 pounds of force per square inch, and last for up to 40 minutes per hour of sleep.

The complications of bruxism include: Damage to the teeth Broken fillings and other dental work Worsening of jaw joint problems Limitation or difficulty in jaw opening and closing Headaches Tooth sensitivity Tooth mobility

Signs ,Symptoms & Consequences Sleep bruxism often exerts remarkably powerful forces on teeth, gums, and joints. Almost ten times — powerful enough to crack a walnut. Why are these forces so high? First, the bruxing activity is not under control of the conscious, rational, brain, which might have moderated or prevented the act from occurring. Second, when one eats, the chewing force is applied in part to the food, not to the teeth; but when one bruxes, the entire force is applied directly to the teeth.

Horizontal forces are applied instead of normal vertical forces. These horizontal forces which involve mandibular eccentric movements are more damaging to periodontium. Bruxism usually associated with REM stage of sleep.

1) Chronic bruxism may lead to sensitive, worn-out, decayed, fractured, loose, or missing teeth . Grinding or clenching break down the enamel, sometimes, in long-term bruxers, reducing teeth to stumps. Instead of a white enamel cover, one often sees the more yellowish and softer dentin. The back teeth of some chronic bruxers often lose their cusps and natural contours, appearing instead flat, as if they had been worked over with a file or sandpaper.

When anterior teeth are affected, their biting surfaces are damaged. As well, the absence of enamel makes it easier for bacteria to penetrate the softer part of the teeth and produce cavities. With time, the condition may lead to bridges, crowns, root canals, implants, partial dentures, and even complete dentures. Interproximal diastema & food impaction can also result from severe wear of posterior dentition.

As long as bruxism continues, the situation keeps getting worse. Thus, "by 40 or 50 years of age, most bruxers have worn their teeth to the degree that extensive tooth restorations must be performed" . Implant complications are more likely in people who habitually clench or grind their teeth. More than 75% of observed implant fractures have occurred in patients with signs and histories of chronic bruxism. Hence, in cases of untreatable severe bruxism, the use of implants is strongly counterindicated (Rangert et al., 1995.; reviewed by Nishimura et al., 1997).

Long-term bruxism often causes changes of appearance, in at least three different ways – a) Damaged, worn-out teeth are not as appealing as healthy teeth. b) As the teeth wear out, they become shorter. As a result, when the mouth is closed, the upper and lower jaws are nearer than they used to be, and so are the nose and chin. The skin now may bag below the eyes and curl around the lips, causing the lips to seemingly disappear . The chin recedes, and the person looks comparatively old.

C) Bruxism involves excessive muscle use, leading to a build-up or enlargement (hypertrophy) of facial muscles. Ex - Masseter. In long-term bruxers, this build-up may lead to a characteristic, square-jaw, appearance. Some patients resort to removing part of the masseter muscle by surgery or injections of toxic materials to reduce muscle size and thus partially regain their former, more aesthetically pleasing, looks .

Long-term bruxers sometimes experience jaw tenderness; jaw pain; fatigue of facial muscles; headaches; neck aches; earaches; and hearing loss. Our body is not built to sustain, night in and night out, the tremendous pressures of bruxing. The teeth, as we have seen, are affected, but in some cases other parts of the head suffer too. We need to note, in passing, that such aches and pains are a functional, healthy, response. It’s the body's way of sending a message: stop bruxing, or else!

Occasional inflammation and blockage of some salivary glands. Bruxism involves muscle overuse. In this case, the masseter muscle become disproportionately overdeveloped and block the opening of the nearby parotid glands. They thus interfere with the flow of saliva into the mouth, causing the saliva to accumulate in the glands. This in turn may lead to periodical swelling, pain, inflammation, and abnormal dryness of the mouth.

Damage the temporomandibular joint. Bruxism is therefore believed by most researchers to be one of the leading causes of temporomandibular disorders . (Glaros, Tabacchi, & Glass, 1998; Israel et al., 1999; Yustin et al., 1993). First warning signs of TMDs are - TMJ discomfort or pain, soreness of jaws and muscles, clicking or popping sounds when opening the jaws or while chewing, and difficulties in fully opening the mouth.

If bruxism continues at this point, these symptoms become more severe. TMDs are often associated with chronic pain which may last months or years. A sufferer may wake up, for example, totally unable to open the mouth. Or the jaw may suddenly lock or dislocate during chewing. Eventually, a difficult surgery of uncertain efficacy may be required .

Malocclusion, or bad bite, is more common among bruxers than in the general population. Misaligned teeth may serve as the cause of bruxism, not as its consequence. Bruxism may often involve more pressure on one side of the mouth than on the other, thereby causing malocclusion. As well, as the teeth wear out and the distance between the upper and lower jaws decreases, over closure may develop - when bruxers close their mouth the front upper teeth do not meet the front lower teeth, but get in front of them.

Apart from wide belief studies have showed that occlusal contact pattern does not influence nocturnal bruxism. Rugh et al – Placed high crown deliberately in 10 subjects, most of subjects had a significant reduction in bruxism during first 2 to 4 nights followed by return to normal bruxing levels. A high posterior occlusal contact does not necessarily increase muscle activity.

Explanation – On contact with poorly fit crown, significant painful peripheral input inhibit CNS induced bruxing activity. As the patient accommodates to the tooth movement & tooth sensation decreases, bruxing resumes. This inhibitory effect is the mechanism by which occlusal appliance therapy decreases bruxism.

There is some evidence of higher levels of mercury in the blood of some bruxers with mercury fillings . Indentations of the lateral borders of tongue. Grinders find themselves in a more uncomfortable position, for many people find the grinding sound unpleasant, irritating, or disturbing . It may wake up light sleepers, for instance, and keep them awake for a long time.

Excessive forces can be generated for extended periods of time that exceed approx. 20 min. of functional tooth contacts, during 24 hr. period Average working force for a natural tooth – 175 psi. Nocturnal bruxist activity – increase to 300 psi. Reported cases of 100,000 to 175000 psi.

Average of 25 bruxist episodes/night. Each episode with durtion of 8 – 9 sec., but can go up to 5 min. Total average bruxing time/sleeping period – 42 sec. One case have been reported of 162 min.

MANAGEMENT Objectives include – a) Reduction of psychological stress. b) Treatment of signs & symptoms of mandibular parafunction. c) Reduction of occlusal irritations. d) Cessation of patterns of neuromuscular habits.

Reduction of psychological stress – Stress management program can be short or long term management strategy, include biofeedback counseling, hypnosis, progressive relaxation, and occupational & lifestyle changes.

Occlusal adjustment is indicated only when there is an obvious deflective interference during mandibular excursions, such as supererupted mandibular 2nd molar during a protrusive function of the mandible. But, to begin with, the role of malocclusion in causing bruxism is in doubt. Also, this technique is irreversible, for it involves the grinding down of some teeth (and artificially restoring others).

Even if malocclusion triggered the bruxing habit, there are no guarantees that its removal will eliminate or decrease bruxing, for by now the habit may have become entrenched and self-sustaining. “No reliable evidence has demonstrated that occlusal interference can cause nocturnal bruxism, or stop it, if the naturally occurring interferences are removed" (Clark et al., 1999).

SPLINT THERAPY Defined as the art & science of establishing neuromuscular harmony in masticatory system & creating a mechanical disadvantage for parafunctional forces. Properly constructed – Supports a harmonious relation among muscles of mastication, disk assemblies, joints, ligaments, bones, teeth & tendons.

Functions – 1) To relax muscles. 2) To allow condyle to seat in CR. 3) To provide diagnostic information. 4) To protect teeth & associated structures from bruxism. 5) To mitigate periodontal ligament proprioception. 6) To reduce cellular hypoxia levels.

Can be classified as – a) Permissive – Allows the teeth to move on splint unimpeded, which in turn allows the condylar head & disk to function anatomically. Ex – bite planes, stabilization splints. b) Non permissive – is a repositioning splint. Ex – Anterior repositioning appliance. c) Pseudo permissive – Soft splints, hydrostatic splints.

Stabilization or muscle relaxation splint – provides stabilization of TMJ, protection of dentition, redistribution of occlusal forces, relaxation of elevator masticatory muscles, decrease in symptoms,reduction of bruxism.

Design – Full arch , acrylic resin, flat plane, can be fabricated for maxillary or mandibular arch. Mandibular is advantageous from perspective of aesthetics & phonetics. Worn during sleeping hrs, may be necessary during waking hrs especially in acute cases.

Anterior Repositioning Appliance Fabricated from hard acrylic. Can be worn only on maxillary teeth, its only occlusal contacts are with the mandibular anterior teeth.

Purpose – to allow for disclusion of the posterior teeth at all times. Effective for management of bruxism with symptoms of myofascial pain that are directly contributory to the parafunctional behavior. Anterior bite plate reduces temporal muscle activity during deglutition in patients with tmj dysfunction.

Because of the possibility of supraeruption of posterior teeth, with continuous wearing, it is worn only during sleeping hrs, when parafunctional habits are most likely. Patient’s occlusion should be monitored closely.

Hydrostatic splint - a water-bearing pressureequalizing appliance sold under the commercial name "Aqualizer" and manufactured by Jumar Corp., Arizona . This prefabricated splint does not require dental impressions or the manufacture of customized appliances. Instead, this disposable splint can be purchased through a dentist, ready-made for use, and is claimed to fit the mouths of most users.

Regarding material of fabrication – Hard splint is more likely to be successful than a soft type splint.. Soft material is not as effective in reducing myofascial pain symptoms as hard acrylic. It can contribute to inadvertent tooth movement & occlusal changes, more difficult to adjust. Indicated – emergency situation like acute retrodiscitis, also as athletic mouthguard.

Okeson (1982) found that acute or chronic symptoms of muscle hyperactivity were lessened signif. with a 24 hr. splint wear. Rugh et al (1989) compared a canine versus molar guidance appliance in eight chronic bruxist patients. The appliances were used for 10 to 14 nights. The two appliances provided nearly equivalent effects on nocturnal bruxism in seven of eight subjects. Clinical examination and subjective pain ratings did not differ with the two guidance patterns.

Long-term reductions in symptoms of bruxism were noted even in patients who wore the splint for six months (Sheikholeslam, Holmgren, and Riise, 1986). Occlusal splints worn at night did not significantly reduce bruxing-clenching activity in bruxing subjects" (Kydd and Daly, 1985). Pierce and Gale (1988) found that bruxing decreased by about 50% during two weeks of splint therapy, but that, following withdrawal of treatment, it returned to baseline levels.

Klineberg (1994) concludes that occlusal splints "will protect the teeth, but will not alter the habit in the long term’’. Complications – Occlusal derangement Decay – caries, gingival inflammation, Degenerative joint disease.

Thus, the splint may or not stop bruxism for a while, it partially protects the teeth, and it moderates grinding sounds.

Alternative methods Wakeful EMG Feedback - increased activity or tenseness can in turn be measured with an electromyograph .

During treatment sessions at home or the laboratory, the patient sits or reclines comfortably. One or more pairs of recording electrodes are then attached to the surface of the skin, in close contact to appropriate muscles (e.g., masseter muscles). These electrodes transmit information about the level of muscle activity to a computer monitor. The patient is instructed to consciously lower that level below a threshold line (also visible on the screen). Gradually, by becoming alert to the presence of muscle tension, patients may develop techniques for reducing that tension, and hence, bruxism.

Massed Negative Practice - Here the patient is told to voluntarily clench the jaw for five seconds, relax it for five seconds, and repeat this procedure five times in succession, six different times a day, for two weeks. Alternatively, the duration of the clenching period may be individually tailored to each patient, with each clench continuing to the point of discomfort . Exercise - Quinn (1995) and many others suggest isokinetic and stretching exercises of the mandible. Such exercises may or may not help alleviate bruxism, and they may perhaps be used to complement other approaches

Drugs - Use of anti-anxiety agents, muscle relaxers, and other drugs . Sleep Feedback - Sleep feedback may involve electromyographic activated alarms. The electrodes of this instrument are placed on the facial area where muscles are located. When the tenseness in muscles due to bruxism exceeds a certain, predetermined, level, the alarm goes off.

The patient is advised to fully wake up after each bruxing episode and to stay awake for a few minutes, usually by performing such meaningless, harmless tasks as hand washing or recording time in a bruxism log . This procedure may fail to correct any bruxing behavior which is associated with muscle tension lower than the predetermined intensity or duration threshold. Another obvious problem is that muscle tension may occur in the absence of bruxism: "numerous other types of orofacial movements unrelated to bruxism . . . can easily be confused with bruxism if only EMG criteria are used for scoring" .

To bypass this problem, many United States patents rely on an alarm system, but take the more reliable bruxing activity itself (instead of enhanced muscle activity) as their point of departure . A commercially available new device, the OralSensor, manufactured by Cycura Corp. of Rocklin, CA, similarly produces an audible tone when bruxism occurs.

Taste-Based Approach to the Prevention of Bruxism Intraoral release of an unpleasant-tasting, safe, substance whenever a patient attempts to brux, thereby drawing the patient's conscious attention to, and precluding, teeth clenching or grinding. Following initial consultation with a bruxing patient, dental impressions of both lower and upper teeth are taken. The impressions are sent to a lab, where an appropriate removable dental appliance is constructed

A dental appliance equipped with posterior rods (22) to  which a capsule can be attached, a curl (26) in one  posterior rod to prevent slippage of capsule, hinges  (30) to secure the appliance to the teeth, and anterior  connection (34) of the two sides to preclude mobility or  swallowing of the appliance

The substance is derived from one or more natural or synthetic, palatable, materials such as hot peppers (capsaicinoids), horseradish, quinine, mustard, ginger, garlic, onion, salt, or denatonium benzoate. The aversive substance is dissolved or suspended in water, vinegar, or other safe, digestible, barely-compressible, fluids.

The liquid is then inserted into, and sealed in, the sleeved capsules, so that each capsule contains little or no air. At its center, the liquid is high enough (roughly 4 mm) to rupture the capsule when the user clenches or grinds, but is not so high as to seriously inconvenience the user or prevent lip contact. The capsule only bursts when the user attempts to bring the maxillary and mandibular teeth together, but not upon mere tooth contact. Experience suggests that such capsules contain enough liquid to reach many taste buds, but not enough to cause any discomfort other than the one associated with unpleasant taste.

CONCLUSION The practitioner needs to distinguish the wear patterns caused by abrasion during normal mastication or oral habits with those caused by bruxism. Patient should be made to understand that, there is no cure for bruxism, instead the condition needs to be managed. Leader in continuing dental education

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