Body movement during sleep in subjects with long-standing bruxing behavior.

PURPOSE: This study aimed to determine whether patients with long-standing nocturnal bruxing behavior present different body movement activity during sleep compared with healthy subjects. MATERIALS AND METHODS: Eleven bruxers and 8 nonbruxers were studied in the sleep laboratory, and motor activity was detected with sensor pads placed under the mattress. Movements simultaneously recorded on videotapes were classified according to their duration and grouped in different types according to their characteristics. RESULTS: Subjects with bruxism had significantly more movements during sleep compared with controls; the difference was especially obvious for movements of short duration (< 5 seconds). The differences became significant from the fourth hour of sleep. These short movements were twitches, jerks, or any sudden, brusque movements of the extremities, but without the periodicity encountered in, for example, periodic limb movements during sleep. No significant relationship was found between the occurrence of masseter activity and movements. CONCLUSION: The findings suggest that subjects with nocturnal bruxism have movement disorders that are expressed not only as grinding or clenching of the teeth, but also as an increase of short-duration body movements during sleep. This reinforces the hypothesis of a central etiology common to both bruxism and short movements during sleep.

Reported symptoms and clinical findings in a group of subjects with longstanding bruxing behaviour.

Signs and symptoms of craniomandibular dysfunction (CMD) and social medical history were reported in 29 subjects, aged 23-68 years, with longstanding (5 years or more) bruxing behaviour. The subjects were selected from answers to an advertisement in the local newspaper. The subjects presented many symptoms of a general character including somatic and psycho-social problems, sleep disorders (72%), and pain (86%). More than half of the subjects (55%) had symptoms every day. Frequent aches in the neck, back, throat or shoulders were reported by 69% and frequent headache by 48% of the subjects. The most common symptoms of CMD were pain in the face or jaws (48%), stiffness in the jaws in the morning (44%), temporomandibular joint (TMJ) sounds (34%) and fatigue in the jaws during chewing (38%) and the most common clinical signs were more than three muscles tender on palpation (76%), TMJ-sounds (55%) and tenderness of TMJ on lateral palpation (66%). There was a statistically significant correlation between frequent tooth clenching and headache, pain in the neck, back, throat or shoulders, sleep disorders and high scores of the clinical dysfunction index (Di). The frequent clenchers had higher score values than the 'non-clenchers' for pain in the face and the jaws; headache; pain in the neck, back, throat or shoulders and the clinical dysfunction index (Di). These findings indicate a causal relationship between frequent tooth clenching and signs and symptoms of CMD, including headache and pain in the neck, back, throat or shoulders and high pathogenicity for frequent clenching. However, the material in this study is small and some precaution must be taken prior to generalized conclusions. More studies are required, especially sleep laboratory investigations, which could perhaps give answers to some of the numerous questions in this unexplored field of odontology.

Personality traits in a group of subjects with long-standing bruxing behaviour.

The personality pattern of 29 subjects, 10 men and 19 women, with a mean age of 37.7 years (range 23-68) was studied by means of a personality inventory (KSP) and compared with the personality traits of a 'normal population'. The bruxers had significantly higher scores in the somatic anxiety and muscular tension scales and lower scores in the socialization scale; that is, the bruxers were more anxiety-prone, had higher vulnerability for psychosomatic disorders and were less socialized. The frequent clenchers (once to twice a week) comprised a special subgroup within the material with higher values in the somatic anxiety, psychic anxiety and muscular tension scales. A strong correlation was found between high values in the muscular tension scale and headache; aching neck, back, throat or shoulders; tooth clenching; number of muscles tender at palpation and the clinical dysfunction index (Di). The results of this study indicate a possible aetiological relationship between personality, tooth clenching and craniomandibular dysfunction (CMD). However, the material was small and some precaution must be taken prior to generalization of the results. Studies on larger material are needed and especially more studies in sleep laboratories.

Descriptive physiological data on a sleep bruxism population.

We studied 24 bruxers (23-67 years old). They often complained of orofacial and bodily pain and presented autonomic symptoms (sweating 23%, palpitations at night 62%, decreased libido 50%); 19% had increased blood pressure requiring treatment, and 65% reported frequent headaches in the morning. Deep sleep and rapid eye movement (REM) were delayed. An average of 167 orofacial episodes developed during the night. The mean number of masseter bursts strictly defined as bruxism was 79, the mean delay for the first occurrence after sleep onset 18 minutes. The majority of bruxism occurred in stage 2 sleep and REM sleep. The mean number of shifts of sleep stages was 70, one-third occurring within the first minute following a bruxing episode, and 15% of bruxing episodes developed after a shift in sleep stage. Electroencephalogram showed alpha-delta pattern in 15% of the subjects. Short-lasting alpha activity was often encountered during the 10 seconds preceding the development of a bruxing episode. Tachycardia developed at its onset, persisting for 10 seconds. We suggest that, as a minor alarm response to endogenous/exogenous stimuli, arousal develops and is often followed by motor activation, such as a burst of bruxing, with, as in any situation when motor activity suddenly increases, a secondary increase of heart activity.