Biofeedback And Relaxation Therapy As Components In
The Treatment Of Nocturnal Bruxism
PAUL W. GWOZDZ
prepared for the
Behavioral Science Course Specialized Seminar
Relaxation, Stress Management, and Behavioral Medicine
Leader: Dr. Paul Lehrer, Ph.D.
November 9, 1994
Copyright © 1997 Paul W. Gwozdz All Rights Reserved
Nocturnal bruxism is the non-functional clenching, grinding or gnashing of the teeth during sleep, a disorder which significantly effects between 5% and 20% of the general population and is found in 20% of dental patients  . There are several approaches that are commonly used in treating nocturnal bruxism. There are dental approaches, which involve a plastic mouth guard designed to protect the teeth and/or change the bite. Dentists often provide what is called "occlusal adjustment", a controversial procedure, in which the surfaces of some of the teeth are modified to fit together better.  An alternative to dental procedures, is therapy which may take the form of biofeedback, relaxation techniques or stress management through behavioral counseling.
Biofeedback is the use of electronic instruments which allow one to measure and monitor muscle activity directly. There are three different forms of biofeedback for bruxism - biofeedback equipment which must be used in the practitioner's office, portable biofeedback equipment that can be worn during the day in the patients own environment, and sleep-time biofeedback equipment that is designed specifically for nocturnal bruxism therapy. The biofeedback section of this paper will concern itself with only the sleep-time biofeedback equipment and its use as reported in the literature since this is appears to be the most popular technique for nocturnal bruxism. This type of biofeedback is also called "sleep interruption biofeedback" and has been shown in several studies to greatly reduce the amount of bruxing during sleep.  The therapy usually requires several weeks of use and will be described in detail later in the next section of this paper through the detailed review of a recent study.
Relaxation therapies involve learning to relax muscles deeply and rapidly enough to be therapeutic, and long enough and often enough to be effective. It usually requires the individual to relax the whole body. This therapy may take several forms including the use of preprogrammed cassette tapes, hypnotism or self-hypnotism. Later in this paper, a case will be reviewed in which a 63 year old woman, who had been bruxing since the age of 3, was very quickly cured of nocturnal bruxing through the use of relaxation techniques including hypnotism.
Stress management through behavioral counseling also appears to be an effective approach to the problem of nocturnal bruxism. Although this approach is outside of the main focus of this paper, one interesting study will be discussed which compared counseling to the use of biofeedback and to the combination of counseling and biofeedback.
An early biofeedback study was reported in 1970 by DeRisi in which three bruxist subjects used a pressure transducer implanted in a silastic mouthpiece while sleeping in their own homes. The equipment presented a loud tone contingent upon rhythmic or lengthy pressure registration. Use of the alarm failed to produce enduring behavior change according to three experiments. More importantly, use of the mouthpiece posed an important methodological problem. It is now apparent that the transducer upset the normal relationships between the tooth surfaces and upset the masticatory system. Depending upon a variety of parameters, the modification of gliding contacts between upper and lower teeth can change the rate of bruxing activity. 
The foundation for contemporary bruxing alarm systems was established in 1972 through the use of epidermal surface recordings of facial EMG activity to define bruxing. It was found that the EMG levels associated with bruxing were easy to identify compared to normal nocturnal behaviors such as swallowing. No incursion into the oral cavity was necessary and the EMG was able to record both audible grinding as well as clenching.  These "facial EMG-triggered alarms" appear to be the basis in most of the nocturnal bruxing alarm studies that have since been performed.
A good demonstrative example of the use of biofeedback is the following paper. In 1989, Feehan and Marsh  reported a single case in which EMG biofeedback behavior was utilized along with an accurately quantified brux core assessment. The subject was an 18 year old woman with mild depression, high anxiety (>95 %-tile), and sharp severe pain in her left TMJ. Assessment of the extent of the bruxing was conducted with the brux cores originally developed by Forgione (1974). The cores consisted of four differently colored plastic sheets laminated together to a total thickness of .02 inches with microdots printed on the upper most surface. The plastic was molded in a vacuum press into upper maxillary plates which were worn by the subject during sleep and during the day. To score the extent of the bruxing, each tooth surface on a plate was individually scored then totalled. A tooth that had two dots ground away received a score of 2. If the first layer under the two dots was exposed, the score would be 4, and so on, until all four layers were ground away and the score for the final are would be 10. 
The authors used biofeedback at home with electrodes taped to her masseter. The threshold on the unit was set to sound on a moderate clenching force but not on swallowing. A different tone was used each night to avoid habituation. When the tone sounded, the subject was required to turn on the light and record the bruxing and the level of pain in her jaw. The purpose for recording the information, though, was to make sure that she was really aroused before returning to sleep. The progress that was reported showed a significant initial reduction followed by a spurt and then a more expected decline with zero awakenings by the 18th day. The initial decline could either be due to a reduction in the frequency of bruxing events or habituation. The threshold of the trigger was lowered during the second phase and the number of events rose significantly which would not be expected if habituation had occurred. Even at this lowered threshold the wakenings dropped off rapidly. Following the final phase, the brux cores were re-administered and a dramatic reduction in the extent of abnormal wear was clear even to cursory visual examination of the cores. Overall, there was a 78% reduction in diurnal bruxing and a 66% reduction in nocturnal bruxing. Even though the patient was still occasionally bruxing after treatment, she reported much improvement in terms of pain and ability to open her mouth for eating. 
Treatment was terminated after 3 weeks and during informal contact with the patient at six months, she reported no significant symptoms.  This study was significant since bruxing was reduced by two thirds after less than a month and the technique was more sophisticated than others since the attachment of the electrode to the jaw provides more accurate feedback and the multiple tone feedback prevents habituation which occurred in the Heller and Strang study (1973). 
In a more recent (1993) and very interesting paper, Steuart Watson of Mississippi State University, combined arousal with overcorrection to completely eliminate bruxing in two married subjects. Since the subjects were married, Watson substituted a spouse for the EMG equipment, though, EMG equipment would probably have been better and appears to be easily resubstituted if available. The overcorrection on top of the arousal appeared to make a significant difference in the final results of this study.
The two subjects were Mark and Jenny. Mark was a 28 year old developmentally normal male with a 6 month history of nocturnal bruxism. Jenny was a 24 year old developmentally normal female with a 3 month history of nocturnal bruxism and had begun bruxing just after graduating college. Both were reported by their spouses to brux the most during the first two hours of sleep. 
As a baseline, their respective spouses recorded the number of time they were awakened by their spouses bruxing during the 2 hour period. These ranged between 4 and 9 times in two hours. During the next phase of the project, Mark and Jenny were awakened by their partners as soon as they were heard bruxing. They were required to sit up briefly (15 - 20 seconds) with their eyes open each time. After a week of steady improvement, a 5 day baseline was reestablished during which bruxing rose again. A second period of arousal followed by baselining was performed on each subject with the expected results - improvement followed by some remission. Then came the interesting part of this study. For the next phase, the subjects were awakened and then were required to complete a 10 minute overcorrection procedure which consisted of face and hand washing, brushing and flossing teeth, rinsing the mouth with water and then mouthwash and repeating the procedure. The spouses were instructed not to provide any social interaction throughout implementation of the overcorrection procedure. After five successive nights with no bruxing, treatment was withdrawn and data was collected for five days.
The average number of bruxes during the baseline for Mark and Jenny was 5.6 and 6.5 respectively. The initial phase of arousal resulted in a 40% decrease for Mark and a 33% decrease for Jenny. WIthdrawal of arousal resulted in increase of bruxing for both subjects. The second phase of arousal further reduced bruxing by an additional 20 % for Mark and 33% for Jenny. Another withdrawal of the arousal intervention resulted in minor escalations of bruxing. After the second return to baseline, the overcorrection procedure was added to arousal. Although the addition of overcorrection did not result in an immediate cessation of bruxing, it reduced bruxing to zero frequency. There was a return to baseline after five successive nights and no further instances of bruxing. Follow-up showed that Mark bruxed once at 3 months post treatment while Jenny had not bruxed at all. 
Watson suggests that the most probable explanation for why arousal was ineffective in treating nocturnal bruxism is that the procedure was not of sufficient aversive strength in that the subject could almost immediately return to sleep following implementation of the procedure. He goes on to suggest that more research in this area is needed.  This author would like to know what would the result be if an electric shock was administered by the EMG device automatically!
B. RELAXATION THERAPY THROUGH HYPNOSIS
Clarke and Reynolds of the Oregon Health Sciences University School of Dentistry reported in 1991 a study of eight subjects who received hypnotherapy for their nocturnal bruxism. The authors used a compact, portable , integrating EMG detector (AL-200B Muscle Activity Integrator, Aaron Laboratories) to monitor levels of masseter muscle EMG activity. The study was setup as a one-group pretest-posttest design. The pretest was a 7 night series of EMG recording during natural sleep in each subject's own home. Treatment consisted of hypnotherapy and posttests consisted of a self-rating of change in symptoms and a repetition of the 7 night EMG recordings as done in the pretest. 
The treatment approach used was referred to as "suggestive hypnotherapy" to identify the use of hypnotic suggestion and to distinguish it from psychotherapeutic hypnosis. A number of inductions, deepening techniques, and hypnotic images were suggested. The phrase "lips together, teeth apart" was presented as a reminder of the relaxed jaw position. Images such as hot towels on the face were also suggested. An audiotape was made with the subject responding to the suggestions. The tape employed the induction and deepening suggestions he or she preferred along with images from the subjects earlier hypnosis. The subject was instructed to listen each night and then drift off to sleep. After a month, the subject returned for a progress check, reported results, asked questions and received a 10 minute hypnosis session for reinforcement. The number of treatment sessions ranged from four to eight and most subjects were completed in 2 to 4 months. 
The author's believe that this study focused on bruxism as a habitual counterproductive response to psychological stress, and the treatment described is essentially a method of using hypnosis to alter the stress response. Nocturnal EMG activity of the bruxers upon completion of the study decreased from between 17% and 75%. Self rating by the subjects indicated most thought that they were much better immediately after the study but there was more variability in the self rating several months after the study. Responses ranged from slightly better to totally symptom free ( in 2 of 8 patients). 
A recent article by Michael LaCrosse or Norfolk, Nebraska in the American Journal of Clinical Hypnosis recounts his experience as a therapist using hypnosis with a bruxer. The patient was a very highly motivated 63 year old woman who had nocturnally bruxed since the age of 3. Dental overlay splints were unsuccessful since she ground through them in her sleep! She worried a lot and often awakened 3 to 6 times per night "with something" on her mind (i.e. worries). His treatment strategy was in two parts which reduces the confidence that the hypnosis was "the" solution but the results were quite miraculous. LaCrosse first assigned the patient to do her worrying during a half hour interval in the least comfortable room in the house. If she started to worry outside of her interval she was to write the problem down but wait to worry about it until the half hour arrived. During the half hour she would write about all of her worries. For the second part of the therapy, she received hypnosis which suggested that there was nothing in life worth being too upset about. She was also instructed that she would sleep comfortably but awaken (without remembering) anytime she began to brux. Within three days, the patient was cured of her bruxing and in 1 month, 20 month, 37 month and 60 month followups, she and her husband reported separately that she was cured. 
C. RELAXATION THERAPY THROUGH BEHAVIORAL COUNSELING
In 1981, Casas, Beemsterboer and Clark, from the University of California at Santa Barbara and LA, performed a study which compared the efficacy of two treatment modalities on night time bruxism - stress reduction behavioral counseling and nocturnal EMG biofeedback. Sixteen subjects were assigned to one of four treatment groups: 1) stress reduction behavioral counseling, 2) sleep interruption biofeedback, 3) stress reduction behavioral counseling AND sleep interruption biofeedback and 4) "waiting list" control group. In the counseling group, the subjects of the study were taught to attribute bruxism to specific cognitions or self-statements rather than to external stimuli or complex inner dispositions. They were also instructed to use their internal speech to get themselves into a more relaxed state. 
The study demonstrated that the three treatments procedures were significantly superior to the no-treatment control group (i.e. greater reduction in EMG activity level). The outcome of the two treatments that made use of stress-reduction behavioral counseling was better than the treatment that solely made use of nocturnal contingent EMG feedback; however, the difference did not approach significance. Finally, the addition of nocturnal contingent EMG feedback to the stress-reduction behavioral counseling did not significantly increase its effectiveness. The authors of the study concluded that stress-reduction skills learned while awake can have a generalized effect on bruxing activity during sleep.  The author of this paper concluded that behavioral counseling is yet an additional approach that may have therapeutic value for nocturnal bruxism though not significantly better than sleep interrupted biofeedback.
To summarize, there are several approaches to the problem of nocturnal bruxism. The most popular in the literature appears to be sleep interrupted biofeedback. The studies indicate that for the training to be effective, the subject must be sufficiently roused from their sleep when caught bruxing. The sensors should be external so as not to disturb the natural bite of the individual. The training needs to be performed for several weeks to avoid extinction and the feedback tone needs to change on a nightly basis in order to avoid habituation.
There were not as many articles on hypnosis or self-hypnosis in the literature searched on MEDLINE. Both articles discussed though concluded that hypnosis was an effective treatment for nocturnal bruxism. The one article that was found about the 63 year old woman was just a single case report, although if based in fact, it certainly should be pursued by further research since the results were close to miraculous.
Behavioral counseling provides an alternative to biofeedback but was not significantly better and would also require more individual attention of a trained instructor or counselor. The sleep interrupted biofeedback system requires much less training but does require the device being available.
A personal comment after reading many of these studies is the noticeable lack of statistically significant study populations. This author has to agree with Cassisi, McGlynn, and Belles, when in 1987 they wrote that " A ... problem characterizing this literature is frequent failure to achieve the basic desiderata of the scientific paradigms that specific experiments represent. Group naturalistic trials, between-group comparisons of alternative treatments, and so forth, have routinely made use of fewer than 10 subjects within experimental conditions. In the absence of predictably robust effects, these sample sizes fall well short of actuarial acceptability (cf. Tversky & Kahneman, 1971)." 
Despite this problem, though, it is clear that further study is warranted and the use of any of these aforementioned techniques should not be precluded in the therapy of nocturnal bruxism.
. Cassisi, Jeffrey E and McGlynn, F. Dudley (1988); Effects of EMG Activated Alarms on Nocturnal Bruxism; Behavior Therapy 19, 133-142.
. Feehan and Marsh (1989). The Reduction of Bruxism Using Contingent EMG Audible Biofeedback: A Case Study, Journal of Behavioral Therapy and Experimental Psychiatry, Vol 20, No. 2, p. 179.
. Schwartz, Mark Stephen (1987). BIOFEEDBACK A Practitioner's Guide, The Guilford Press, p. 298
. Schwartz, pp. 299-300.
. Schwartz, p.298.
. Cassisi etal. p 14.
. Cassisi etal. p. 15.
. Feehan and Marsh, p. 180.
. Feehan and Marsh p. 181.
. Feehan and Marsh, p. 181.
. Feehan and Marsh, p. 182.
. Feehan and Marsh, p. 182.
. Watson, T. Steuart (1993). Effectiveness of Arousal and Arousal Plus Overcorrection to Reduce Nocturnal Bruxism, Journal of Behavioral Therapy and Experimental Psychiatry, Vol 24, No. 2, p. 181-182.
. Watson, p.182.
. Watson, p.183-184.
. Watson, p. 184.
. Clarke, J.H. and Reynolds, P.J. (1991). Suggestive Hypnotherapy for Nocturnal Bruxism: A Pilot Study, American Journal of Clinical Hypnosis, Vol 33, No. 4, p. 249.
. Clarke and Reynolds, p. 250.
. Clarke and Reynolds, p. 252.
. LaCrosse, Michael B. (1994). Understanding Change: Five-Year Follow up of Brief Hypnotic Treatment of Chronic Bruxism, American Journal of Hypnosis , 36:4, pp. 277-281.
. Casas, Jesus Manuel, Beemsterboer, Phyllis, and Clark, Glenn T. (1982). A Comparison of Stress-Reduction Behavioral Counseling and Contingent Nocturnal EMG Feedback for the Treatment of Bruxism, Behav Res. Ther, Vol 20, pp. 9-12.
. Casas et al., p. 13.
. Cassisi, McGlynn and Belles (1987). EMG-Activated Feedback Alarms for the Treatment of Nocturnal Bruxism: Current Status and Future Directions. Biofeedback and Self-Regulation, Vol. 12, No. 1, p. 26-27.
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