[Clinical observation of bruxism-induced wear facets and the influence of wear facets on masticatory function].

The wear facets produced 10 years ago were compared with the present ones in a 35-year old patient with bruxism. The electromyographic data of 10 years ago were also compared with the current data. Current mandibular kinesiograph data were also measured. The total area of the present wear facets was increased approximately 2.3 times those of 10 years ago in the upper teeth, and approximately 2 times in the lower teeth. However, the number of current wear facets of the upper and lower teeth was reduced, compared to that of 10 years ago. The Gothic arch tracing revealed a difference of about 1 mm between the centric occlusion and the centric relation. The patient had a unilateral balanced occlusion and a grinder-type chewing pattern. The free-way space, was in a normal range, approximately 2 mm. The raw electromyographs during sponge chewing 10 years ago differed from the present findings, although the chewing rhythm was the same.