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Journal of Oral Science, Vol. 43, No. 2, 73-83, 2001

Review

A bibliographical survey of bruxism with special emphasis on

non-traditional treatment modalities

Moti Nissani

Interdisciplinary Studies Program, Wayne State University, MI 48202, USA

(Received 21 June 2000 and accepted 12 March 2001)

Abstract: After proposing a common-sense

definition of bruxism, this partial review distills its various symptoms and consequences from the literature. That literature suggests that the splint-the most popular

treatment modality-falls short in some respects. The research literature is even less sanguine about the

efficacy of such other traditional therapies as sound alarms and stress reduction. Given the limited success

of traditional approaches, and given, moreover, the high incidence of bruxism and its harmful consequences,

clinicians may occasionally be interested in experimenting with non-intrusive, safe, less widely known, treatment modalities. To meet this need, this

review-unlike all other reviews of the subject-focuses on such comparatively unpopular or recent approaches.

(J. Oral Sci. 43, 73-83, 2001)

Key words: bruxism; clenching; grinding; treatment;

taste aversion.

Traditional treatments of bruxism are not always

successful (1,2). By a very wide margin, the splint is the most widely used treatment, yet, a literature review discloses

that it often fails to stop either teeth clenching or grinding. The literature likewise shows that other popular approaches

(e.g., sound alarms) often fail to stop this habit. Given the limited success of these approaches, and given, moreover, the high incidence of bruxism and its harmful consequences,

clinicians may occasionally be interested in experimenting

with non-intrusive, safe, less widely known, treatment

modalities. To meet this need, this partial bruxism review-unlike all other reviews of the subject-focuses on such comparatively unpopular or recent approaches.

What is bruxism? The word bruxism is taken from the Greek word

brychein: gnashing of teeth. No standard terminology exists, so we must try to clarify the confusion that still surrounds this subject. Bruxism can perhaps be defined as the involuntary, unconscious, and excessive grinding or clenching of teeth. When it occurs during sleep, it may be best referred to as sleep bruxism. A few people, on the other hand, brux while they are awake, in which case the condition may be referred to as wakeful bruxism.

The above terms are preferable to the widely-usednocturnal and diurnal bruxism, for the simple reason that one may engage in sleep bruxism during the day and in wakeful bruxism during the night. The distinguishing

factor between these related conditions is sleep, not sunlight.

All forms of bruxism entail forceful contact between the biting surfaces of the upper and lower teeth. In grinding,

this contact involves movements of the lower jaw and unpleasant sounds, which often awaken housemates. Clenching, on the other hand, involves silent, sustained,

forceful tooth contact unaccompanied by mandibular movements.

It is important to note that the difference between bruxers

and non-bruxers is one of degree, not kind. Most people

probably grind or clench their teeth at one time or another, but such behavior does not a bruxer make. Moreover, some

people may be able to sustain the bruxing forces involved with no apparent ill effects. Thus, we should perhaps talk

about bruxism only when the habit is persistent enough, frequent enough, long enough, or intense enough to damage

the teeth and to lead to other complications. One's grinding

Correspondence to Dr. Moti Nissani, Interdisciplinary Studies Program, 2nd floor, 5700 Cass, Wayne State University, Detroit, MI 48202, USA Tel: 248.427.1957 Fax: 313.577.8585 E-mail address: moti.nissani@wayne.edu

74

or clenching of teeth fall under the rubric of bruxism only

when they have already affected, or are expected to affect,

one's well being.

Biblical references

Bruxism is probably as old as humanity itself. The Bible is often cited in this context, even though its relevance to the modern concept of bruxism is dubious. A typical

passage appears in Job, chapter 16, verse 9: "He teareth me in his wrath, which hateth me: he gnasheth upon me

with his teeth; mine enemy sharpeneth his eyes upon me." In the New Testament, "wailing and gnashing of teeth" is

often wished upon sinners and heretics. Another interesting

passage appears in Luke 9: 17-18: "Master, I have brought unto thee my son, which has a dumb spirit. And

wheresoever he taketh him, he teareth him: and he foameth, and gnasheth with his teeth, and pineth away." In the Bible, then, teeth grinding seems to accompany such

extreme emotional states as hate, anguish, fear, and

possession by spirits. This is perhaps suggestive of our contemporary conceptions of wakeful teeth grinding. The Bible, however, makes no explicit reference to wakeful

clenching or to sleep clenching or grinding.

Incidence of bruxismNo hard and fast figures on the frequency of bruxism

are available. Most people unconsciously grind or clench

their teeth now and then, so the key in the diagnosis of bruxism is not the presence or absence of the habit, but

its frequency, destructiveness, social discomfort, or physical symptoms (3). Moreover, over 80% of all bruxers may

be unaware of the habit (4), or ashamed of it, so they may dismiss evidence that they do in fact engage in self-

destructive behavior. Also, it may take years for the first visible signs of worn teeth to appear; yet, often it is these signs that lead to a diagnosis of past or present bruxism.

For these reasons, estimates of the prevalence of bruxism range from 5% to 100%. For the U.S. population, current estimates often settle on the 5-20% range.

Regardless of the exact number, the figures are disturbing.

At the very least, one out of twenty people brux. More likely, one out of four does. Inarguably, then, bruxism is

a widespread behavioral pattern that adversely affects a significant fraction of the world's people.

Etiology of bruxism The etiology of bruxism is controversial and uncertain

(1,4). At present, the causes are suspected to be many, to overlap each other, and to vary from one patient to another.

Putative causes include stress, personality types, allergies,

nutritional deficiencies, malocclusion, dental manipulations, introduction of foreign substances into the mouth, central

nervous system malfunction, drugs, deficient oral

proprioception, and genetical factors.

Symptoms, signs, and consequences of

bruxism Sleep bruxism often exerts remarkably powerful forces

on teeth, gums, and joints. One estimate puts it at three

times the forces generated during chewing (5), while

another puts it at ten times—powerful enough to crack a

walnut. While not a life-threatening condition, the sustained

application of such forces often impairs the quality of life

of affected individuals. Some suspected symptoms and consequences of chronic bruxism are:

I. It may lead to sensitive, worn-out, decayed, fractured, loose, or missing teeth (6). 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"

(7). For example, implant complications are more likely in people who habitually clench or grind their teeth (8,9).

In one study, more than 75% of observed implant fractures occurred in patients with signs and histories of chronic

bruxism. Hence, in cases of untreatable severe bruxism, the use of implants is strongly counterindicated (9,10).

II. Long-term bruxism often causes changes of appearance, in at least three different ways.

To begin with, damaged, worn-out teeth are not as

appealing as healthy teeth. Second, 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

(11). The chin recedes, and the person looks comparatively old.

Third, bruxism involves excessive muscle use, leading

to a build-up or enlargement (hypertrophy) of facial muscles, especially those of the jowl (where the masseter

muscle is located). 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 and thus partially

regain their former, more aesthetically pleasing, looks

(13, 14). III. Long-term bruxers sometimes experience jaw

tenderness, jaw pain, fatigue of facial muscles, headaches, neck aches, earaches, and hearing loss (15).

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IV. Bruxism occasionally causes inflammation and blockage of some salivary glands. Most likely, the masseter

muscles 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 (16).

V. Bruxism may also damage the temporomandibular

joints (TMJs). Bruxism is therefore believed by most researchers (but not all, cf. 17) to be one of the leading

causes of temporomandibular disorders (TMDs) (18-20). To be sure, besides bruxism, TMDs may be caused by

such things as whiplash, a hard blow to the chin, malocclusion, nearby tumors, orthodontic treatment,

arthritis, long-term scuba diving, or prolonged violin

playing. But the important point here is that chronic bruxism may induce TMDs, and that TMDs can be

unpleasant. Often, the 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. It is worth remembering that a "TM disorder, although

not being life threatening, is certainly life altering." It can, in fact, "devastate its victim" (21). First, patients must

contend with chronic pain and other symptoms. Second,

often, there is much anguish and humiliation before the condition is correctly diagnosed. Indeed, "the average TM

disorder patient has been seen by at least seven physicians, dentists, psychologists, or other health professionals. Of these patients, 7 out of ten have been incompletely

diagnosed or misdiagnosed" (21). Third, "it is unrealistic

to expect" a cure for TMDs. "At best, we are only managing signs and symptoms to the best of our ability within the framework of the patient's ability to cope with the disorder"

(22). The best thing we can do for our bruxing patients, then, is to help them control bruxism and thereby minimize

the chances of temporomandibular complications. Conversely, when TMDs are traceable to bruxism, it is

more or less useless to treat these disorders without addressing their underlying cause: "Surgical procedures

that alter anatomic relationships without addressing factors contributing to pathogenesis may be more prone to failure and recurrence of [TMD] symptoms. It is clear that

excessive loading on articular tissues is one of the causative factors that must be identified and addressed by all clinicians

treating patients with TMJ pathology" (19). VI. Dental fillings often contain solid mercury. Mercury,

in turn, is not entirely safe. Right now, the consensus of

the dental community in the USA is that the advantages of using mercury outweigh the comparatively small risks.

According to the American Dental Association, for example, "there is insufficient evidence to justify claims

that mercury from dental amalgams has an adverse effect on the health of patients" (23). In bruxers, though, the situation is a bit more complicated, for there is some

evidence of higher levels of mercury in the blood of some bruxers with mercury fillings (24).

VII. Malocclusion is more common among bruxers than in the general population. To be sure, misaligned teeth may serve as the cause of bruxism, not as its consequence.

But 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

Fig. 1 The young man (left frame) has normal teeth. By middle

age (middle frame), bruxism flattened his teeth and changed his appearance somewhat. By old age (right frame), the change is even more remarkable (12, p. 227).

Fig. 2 Facial appearance of a 13-year-old bruxer with left masseteric hypertrophy (arrow on right) (13).

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distance between the upper and lower jaws decreases,

overclosure may develop. VIII. Clenchers, as we have seen, destroy their teeth

silently; hence, their habit does not directly impinge on

members of their household. Grinders find themselves in

a more uncomfortable position, for the people they interact with often find the grinding sound offensive, irritating, or

disturbing (25,26). It may wake up light sleepers, for instance, and keep them awake for a long time.

The picture that emerges, then, is of a habit that is not life threatening in any way. Moreover, in its initial stages,

because bruxism only involves minor symptoms and inconveniences, it is often ignored by both patients and

clinicians. At a certain stage, however, the symptoms begin to noticeably affect one's quality of life. It is typically

at this stage that a patient seeks professional advice.

Splints By far the most common treatment regime for bruxism

embodies the time-honored procedure of splint therapy

(27,28). In the United States alone, some 1.6 million splints (aka nightguards, biteguards, occlusal splints, biteplates, removable appliances, or interocclusal orthopedic

appliances) are annually prescribed by dentists in an effort to combat bruxism (29). Much current research on the treatment of bruxism has been centered on the use of such

dental appliances. There are many variations of this appliance. The most

common is the customized, hard acrylic, variety.

Some dentists prefer a customized appliance made of soft, rubber-like, elastomeric material. Another, far less

popular, variation is the hydrostatic splint, a water-bearing

pressure-equalizing appliance (30). This prefabricated disposable splint does not require dental impressions nor

the manufacture of customized appliances. Instead, it can be purchased through a dentist, ready-made for use, and it is alleged to fit the mouths of most users.

In view of their wide use, the central question about all splints is: Just how effective are they in treating bruxism?

At the moment, a clearcut answer to this question is unavailable. Sheikholeslam, Holmgren, and Riise (31), for instance, report long-term reductions in symptoms of

bruxism in patients who wore a splint for six months. Others, however, feel that the splint does not diminish

bruxing behavior over the long term, nor alleviate most symptoms and consequences. They insist, in fact, that the

splint may only provide a measure of protection for the teeth, and, in the case of grinders, a moderation of the sound.

And even this is purchased at a price: the splint is uncomfortable to wear, some patients remove it during

sleep, and it may negatively affect one's bite, cause tooth

decay, and lead to degenerative joint disease (32).

Given the popularity of the splint, and some of the claims that have been made about its effectiveness, it may

be worth while to cite at some length what appears to be,

at this point, the emerging majority view in the research community: "The most common 'treatment' is a rubber device, worn over the teeth at night, called a mouthguard.

This does not actually prevent or cure the bruxism, but it

will prevent damage to the teeth when bruxism occurs"

(33). "Occlusal splints worn at night did not significantly reduce bruxing-clenching activity in bruxing subjects"

(3). Pierce and Gale (34) found that bruxing decreased by about 50% during two weeks of splint therapy, but that, following withdrawal of treatment, it returned to

Fig. 3 A 1942 rubber splint, constructed to alleviate teeth

grinding (28).

Fig. 4 A contemporary, acrylic, hard splint worn by a bruxism

patient.

Fig. 5 The hydrostatic splint (30).

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baseline levels. Klineberg (35) concludes that occlusal

splints "will protect the teeth, but will not alter the habit

in the long term." Splints, he says, become "worn when in use and wear and tear on the splint indicates continuation of the habit, even though patient[s] might report that they

were no longer aware of clenching their teeth. The longer term effects of splint therapy indicate that clenching returns

after the splint has been removed, or with continued use of it." According to Rugh et al. (36), splint therapy is

effective at first, but "the usual trend with longer treatment is to lose its effects. In other words, one usually sees a

dramatic decrease or increase in EMG activity the first few nights of splint usage, followed by a gradual return to

pretreatment EMG values." Perl (8) says that, "there is no way of preventing the clencher or bruxer from engaging in such parafunctional habits. Regardless, the clinician may

be able to decrease the potential for destruction by adding a nightguard to the treatment protocol." Dao&Lavigne

(37) say that although "splints may limit dental damage, their efficacy remains unestablished." The comparative

ineffectiveness of the traditional splint is also "borne out by the common clinical finding that patients may bite

large teeth marks into night bite guards and frequently fracture appliances" (38).

Moreover, the use of such splints may sometimes

adversely affect the patient's occlusion, e.g., cause an open bite (39,40): "As with any technique, splint therapy

has both positive and negative effects. If the complications are known and understood, they can be included in the

treatment planning process and discussed with the patient before treatment begins. The most common complication

of splint therapy is the creation of changes in the patient's occlusion" (32). Another complication of splint therapy

is decay under the splint, which may in turn cause caries and gum inflammation. Still another problem is severe

degenerative joint disease (32).

Sleep feedback: sound alarms In the treatment of bruxism, sleep feedback may involve

electromyographic (EMG)-activated alarms (41). Bruxism requires tensing of certain facial muscles. This tensing

involves an increase in electrical activity of the muscles, which can in turn be recorded by an electromyograph. The

electrodes of this instrument are placed on the facial area where these muscles are located. When the tenseness

exceeds a certain, predetermined level, an alarm goes off. The loudspeaker can be free standing, or, to prevent waking

others, connected to earphones that the patient wears during sleep.

Most clinicians recommend overcorrection right after

the alarm sounds. The patient is advised to fully wake up

after each presumed 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 (41). In either case, the alarm can be either turned off manually by the wakened bruxer or turned off

automatically when the sleeper's facial muscles relax. This approach is fairly unintrusive-one needs not insert

anything into the mouth, but needs only attach electrodes externally, to the face. On the other hand, this procedure

may fail to correct any bruxing behavior that 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" (42). So a patient may

sometimes not receive a signal when a signal is needed, while at other times a patient may be jolted out of deep

sleep for nothing. To bypass this problem, many patents still rely on an

alarm system, but take the more reliable bruxing activity

itself (instead of enhanced muscle activity) as their point

of departure. When the pressure exceeds a predetermined level, the alarm sounds.

Fig. 6 Splint-induced open bite: after wearing a hard splint

for a year, this patient can no longer bring his front teeth

together.

Fig. 7 A typical sound alarm setup for the treatment of bruxism

(Source: U.S. Patent 5,078, 153, Jan. 7, 1992).

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Feedback approaches suffer from machine breakdowns and are often unsightly, invasive, intimidating, and

expensive; they thus do not lend themselves readily to wide use, and especially not to long-term use. As well, they are

only partially effective. In evaluating EMG-activated studies, Pierce and Gale (34) found that bruxing only

decreased by about 50% during two weeks of biofeedback therapy, but that, following withdrawal of treatment, the condition returned to baseline levels. Piccione et al. (43),

to cite another example, found that "biofeedback does not appear to be effective in reducing nocturnal bruxing,"

probably because, over time, "subjects learned to ignore the tone and to maintain sleep."

Other traditional approaches

Space only permitted a cursory look at two traditional approaches-the splint and sound alarms. Here we need

only say in passing that similar uncertainties apply to electrical stimulation (44), psychotherapy of all kinds (45, 46); hypnosis, massed negative practice (4,34), exercise

(47); drugs; and equilibration therapy (48, 49). Undoubtedly, such traditional approaches as the splint,

sound alarms, and stress reduction will continue to be used in the future, sometimes successfully. But one often

runs across a patient who has tried one or more of these approaches, yet whose bruxism is unabated. Occasionally,

traditional approaches may be deemed unsuitable, for a variety of reasons. In such cases, familiarity with the following options may be of some use to dentists,

physicians, and clinical psychologists.

Wait and see In some cases, bruxism may vanish spontaneously. In

others, grinding and clenching may occur so seldom, or are so weak, as to hardly justify any action.

In particular, young children often require different therapeutic approaches than adults. To begin with, the

damage to their teeth is transitory for the most part, for only the primary teeth may be affected, not the permanent teeth. Moreover, bruxism in children usually resolves

spontaneously. In one study, for example, 126 children between the ages of 6 and 9 years were diagnosed with

bruxism. Five years later, upon re-examination, only 17 children retained the bruxing habit. Thus, juvenile bruxism

is probably "a self-limiting condition which does not

progress to adult bruxism and which appears to be unrelated to TMJ symptoms" (50). This suggests that, "observation and reassurance, rather than intervention, are warranted in most cases" (4). Obviously, however, even in children,

when the damage is severe (15), or when the habit persists,

treatment is mandatory.

Thus, if bruxism occurs only sporadically and

intermittently, especially in children, waiting may provide the best strategy. If the condition does not spontaneously

disappear in a few months, keeps recurring, or is accompanied by worrisome side effects (such as hearing

loss or locked jaw), then action is required.

Bruxism as a side effect of drugs and medications

In some cases, bruxism may be traceable to drugs.

Smoking (51) and alcohol (33) may cause, or at least exacerbate, the condition. Antidepressant and antipsychotic

medications may trigger bruxism in non-bruxers (52,53). For example, within a few days of initiating velafaxine

therapy for depression, a man with a bipolar disorder developed bruxism. In another study (1), daily intake of

the antidepressants fluoxetine (=prozac) or sertraline triggered sleep bruxism in four non-bruxers. It should be

noted that the effect of anti-depressants is still uncertain

(54). Still, clinicians need to bear in mind the possibility that drugs or medications may induce or exacerbate bruxism.

Clinicians should routinely inquire about their patients' habits of consuming tobacco, alcohol, and antidepressants. Cutting down on smoking or drinking may help improve

bruxism. If bruxism developed shortly after the beginning of antidepressant therapy, the prescribing clinician should

be notified and consulted about the desirability of reducing the dose of the antidepressant, switching to another

antidepressant, or taking a drug that will counteract the bruxism-inducing effect of the antidepressant. Thus, the

effects of venlafaxine may be counteracted with gabapentin; while the effects of fluoxetine and sertraline may be

neutralized with buspirone.

Nutritional supplements Magnesium's vital role in nerve and muscle function led

at least two researchers to the suspicion that bruxism may

be traceable to insufficient consumption, or inefficient utilization, of this metal. Magnesium-deficient diet is said to cause frequent teeth grinding in both sleeping and

awake pigs (55). In humans, the suggested treatment involves magnesium supplements. According to Ploceniak

(56), for instance, prolonged magnesium administration nearly always provides a cure for bruxism. This confirms the earlier report of Lehvila (55), which claimed remarkable reductions (and sometimes even disappearance) in the

frequency and duration of grinding episodes in six patients who took, once a day, a tablet of assorted vitamins and

minerals (which included 25 mg { in children or 100 mg in adults I of magnesium), for at least five weeks. When

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the supplements' intake stopped, the symptoms returned. Earlier, a similar logic led Cheraskin & Ringsdorf (57)

to study the effects of nutritional supplements on teeth

grinders or clenchers. Of these, 16 took calcium, vitamin A, vitamin C, Vitamin B5 (pantothenic acid), iodine, and vitamin E. When surveyed a year later, they reported that bruxism vanished. In contrast, the 15 bruxers who only took vitamins A, C, E and iodine showed no improvement. It seemed reasonable to conclude that the active agents were calcium and pantothenic acid (vitamin B5).

More research is clearly needed in this area. Indeed, if such claims apply to even a small proportion of bruxers, they merit a close look because taking these supplements is comparatively convenient, safe, and free of side effects.

Until such claims are confirmed, narrowed down, or refuted in a large-scale, double-blind study, the best strategy may involve taking the following on a daily basis: magnesium (approximately 100mg), calcium (150mg), and pantothenic acid (50mg), combined with at least the following: vitamins A (1,000IU), C (300mg), E (60mg), and iodine (0.1mg=100 mcg). If bruxism subsides,

patients should be advised to continue taking these pills. If no improvement is observed after 8 weeks or so, this approach may be given up.

Notes: 1. In these nutritional studies, bruxers typically take a

number of vitamins and minerals, not just one; thus, it is not yet possible to pinpoint the effective nutritional agent. Moreover, these supplements often work synergistically or cooperatively; so a few minerals and vitamins need to be taken to correct a deficiency in one. That is why, until we know more about the subject, all the supplements above should be taken, not just magnesium or calcium.

2. The available evidence tells us little about optimal dosages, so there is an element of uncertainty in deciding how much to take.

3. Children should take proportionately less. For instance, an eight-year-old weighing about 32 kg should take about half the recommended dosage.

4. Magnesium should be avoided in cases of renal impairment and acute dehydration. It should not be taken if it causes diarrhea, other adverse reactions, or if it interferes with other medicines. One should refrain from

prescribing more than 100 mg a day, as taking too much, or prolonged treatment, may cause fatigue and respiratory

problems. Taking too much magnesium may even cause hypermagnesaemia, leading to nausea, vomiting, lethargy, and blockage of the bladder. As in the case of most drugs, dosage should be roughly determined by weight. In my view, roughly 1.5 mg a day per kg of body weight is all

that should be taken (so a person weighing 66 kg needs to take no more than 99 mg of magnesium).

5. A large-scale experiment on the effectiveness of nutritional supplements is long overdue.

Vacuum prevention Long (58) believes that "to clench the jaw for a long time,

an intraoral vacuum must be formed and maintained." To

prevent the formation of such vacuum, one may construct the simple appliance shown below. Over this appliance

two plastic straws are fitted, which are in turn held in

place with two rubber washers aimed at preventing the creation of vacuum.

It remains to be seen just how effective this approach is. In view of its simplicity, low cost, and few probable

side effects, further experimental and clinical evidence

would be of interest. In the meantime, some reservations come to mind.

The appliance itself may often float in the mouth of a

sleeping patient, or even be expelled. The evidence that

a vacuum is required for sustained clenching is sketchy, at best. The appliance is said to prevent prolonged clenching, not to prevent clenching of short duration, nor

Fig. 8 This anti-clenching appliance attempts to prevent

vacuum formation (58).

Fig. 9 The same appliance worn by a clencher.

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to prevent grinding. Thus, it may merely lead to a change in the pattern of bruxing, with more numerous bouts of

shorter duration, so that the total amount of bruxing remains the same. The total effect may be equivalent to

breathing through the mouth, which is not as healthy or comfortable as breathing through the nose. Indeed, it is

difficult to see how the same effect could not be achieved by the simpler means of plugging one's nose before going

to sleep. The appliance cannot serve as a cure; it must be worn to mitigate clenching. Apart from subjective patient

reports, it would be difficult to know whether this treatment is effective.

Sleep feedback: human alarms

One long-term experiment (26) involved a 28-year-old man with a six-month history of sleep grinding and a 24-

year-old woman with a three-month history of sleep grinding. The treatment only involved the first two hours of sleep and consisted of the following sequence: 1. Baseline: During the first few nights, the spouses of both

grinders were instructed to merely record grinding noises. 2. Waking: For the next few nights, they woke their

spouses when grinding noises were heard. 3. Baseline. 4. Waking. 5. Baseline. 6. Waking plus overcorrection

(an enforced wakeful period-performing a series of meaningless activities, e.g., face washing for ten minutes

before going back to sleep). 7. Baseline. 8. Follow-up recordings taken at intervals of up to 18 months post-

treatment. In both individuals, almost complete cessation of grinding occurred.

In a similar study (25), ice was applied to the cheeks of

two profoundly retarded wakeful grinders when they were heard bruxing. Significant long-term reductions in the

incidence of bruxism were observed in both patients. Along with the magnesium therapy discussed earlier,

such little-used behavioral approaches deserve further study. Yet, even if these approaches are shown to be effective in a large-scale investigation, they suffer from

obvious shortcomings. They are inapplicable to clenchers. Moreover, the four individuals in these two studies may have simply learned to grind inaudibly, clench instead, or

shift grinding behavior to periods when feedback was

unavailable. Such approaches depend on the presence of another individual nearby, and on the willingness of that individual to lose sleep and provide the needed feedback

over a period of many months.

The NTI clenching suppression device This mini-splint is described as "a patented pre-

fabricated, easily retro-fitted anterior-point-stop device, which suppresses clenching intensity in all excursive and

protrusive movements" (59). The device is said to reduce clenching behavior.

Like the traditional splint, the device may cause an annoying anterior open bite. As well, as in the case of all

other bruxism claims, a systematic, large-scale, double-blind study remains to be carried out. At present, we

simply do not know if this device is more or less successful than the traditional, much larger, hard splint.

A taste-based approach to the prevention

of bruxism Here, a mildly aversive, safe liquid (e.g., sea water), is

inserted into, and sealed in, small wax or plastic capsules

(2). Two capsules are attached to a specially designed dental appliance, which comfortably and securely places the capsules between the lower and upper molars. The

appliance and capsules are worn at night or at other times when bruxism is suspected to occur. Whenever bruxism

is attempted, the capsules rupture and the liquid is released into the mouth. The liquid then draws the bruxer's conscious

attention to, and forestalls, any attempt of teeth clenching or grinding. After replacing the capsules, sleeping patients resume sleep while awake patients resume their normal

activities.

Fig. 10 Two views of the NTI clenching suppression system

(59).

Fig. 11 A removable appliance supporting liquid-filled capsules

(2).

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On the positive side, this approach involves wearing a

comfortable dental appliance similar to a child's retainer; hence (unlike the splint), it is probably not associated

with any worrisome side effects. It is based on the known,

remarkable, effects of taste stimuli in aversive conditioning, and on documented research that the sleeping brain is

capable of learning. It is less cumbersome than sound alarms, and, unlike sound alarms, it virtually precludes

habituation. When worn, it eliminates bruxing behavior. Moreover, this appliance (attached to wax capsules) can

be used to diagnose bruxism. On the negative side, the first couple of weeks of therapy

require will power. Also, as in the case of all other bruxism

therapies, a large scale, double-blind, experiment confirming the effectiveness of this approach has yet to

be carried out.

Conclusion

No attempt at comprehensiveness has been made here: Many bruxism therapies have only been mentioned in

passing. Likewise, no effort has been made to resolve the many controversies about the etiology of bruxism, nor about

bruxism's complex linkage to temporomandibular disorders. Instead, a common-sense definition of bruxism has been

proposed and its many symptoms and consequences have been distilled from the vast literature. That literature suggests that the splint-the most popular treatment

modality-falls short in some respects. The research literature is even less sanguine about the efficacy of such

other traditional therapies as sound alarms and stress reduction. More research, modifications of traditional

approaches, and new approaches, are badly needed. In the meantime, a few recent or little-known claims deserve

additional study and they may aid the management of

intractable cases.

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