Effects of sleep bruxism on periodontal sensation and tooth displacement in the molar region.

The purpose of this study was to investigate the effects of sleep bruxism on periodontal sensation and tooth displacement in the molar region. Twenty-eight (28) subjects lacking objective or subjective abnormalities in stomatognathic function were divided into two groups representing bruxers (n=14) and controls (n=14). Sleep bruxism was confirmed based on the nocturnal electromyography activity of the masseter muscle. Periodontal sensation was assessed based on interocclusal tactile threshold (ITT), which refers to the minimal thickness that can be detected between the occlusal surfaces of the teeth. ITT was measured in the first molar region. Displacement of teeth during clenching was measured using a two-dimensional tooth displacement transducer. Statistical analysis of the differences in ITT and tooth displacement between the bruxers and controls was performed by Mann Whitney U-test (p < 0.05). Mean ITT for bruxers was significantly lower than that for controls (p < 0.01). The mean displacement of both the maxillary and mandibular first molar for the bruxers was significantly larger than that for the controls (p < 0.05). The results of this study suggest that sleep bruxism affects both periodontal sensation and tooth displacement.