A Study of Bruxism During Sleep. Development of a New Method for Analyzing Jaw Movement during Sleep and the Difference between Buruxism Conscious and Unconscious Groups.

Abstract

Bruxism has been considered to be one of the important factors accelerating the progression of periodontal lesions, but the detailed mechanism of bruxism has not yet been established. The purpose of the present investigation was to develop a new method for analyzing jaw movement during sleep and to examine the difference between bruxism conscious and unconscious groups. A jaw movement recording system developed by us consisting of two light emitting diodes (LED) and two photoelectric-displacement detectors (photentiomatic) was used to record jaw movement in two directions (lateral and anterior). Four adult volunteers ranging in age from 27 to 32 were selected. Two of them were conscious of bruxism and other two were not. Each subject participated in our experiment for five nights, there being two or more nights of adaptation period before the experimental period. We recorded masseter muscle activity, tooth contact, grinding sounds and jaw movement during sleep, and analyzed the data. The results obtained were as follows: 1. We were able to record jaw movement during sleep using this system. 2. Each bruxism pattern was classified into grinding, clenching or others, using this system. 3. The proportion of grinding was significantly higher in the bruxism conscious than in the bruxism unconscious group. On the other hand, the proportion of clenching was significantly higher in the unconscious group. 4. The proportions, of the total duration spent in grinding, clenching and others in each subject were similar every night.