Relationship of tooth grinding pattern during sleep bruxism and temporomandibular joint status.

The purpose of this study was to investigate the relationship between tooth grinding pattern during sleep bruxism and temporomandibular joint (TMJ) status based on condylar movement. Fifty subjects (21 males and 29 females) wore a bruxism recording device, BruxChecker, to record their grinding pattern during sleep bruxism. The grinding pattern was categorized into laterotrusive grinding (LG) and mediotrusive side grinding (MG). Furthermore, LG was divided into three types; incisor-canine (IC), incisor-canine-premolar (ICP) and incisor-canine-premolar-molar (ICPM) type. Condylar movements were also recorded using computer-aided axiograph to evaluate the signs of TMJ hypermobility. The average maximum separation distance of excursion and incursion and the average maximum condylar lateral deviation during protrusion/retrusion and open/close movements in the ICPM type and the ICPM+MG type were larger than those of the IC and ICP types. While reconstructing the occlusion, it is important to take into consideration the presence of bruxing patterns of the ICPM type and mediotrusive side grinding.