中心位置咬合干擾對下顎運動之影響

This study was to evaluate the influence of a centric occlusal interference on jaw movement. The subject material consisted of five women and five men having a mean age of 28.1 years. Subjects were all in good general health and were without symptoms and signs from temporomandibular joint. A centric occlusal interference (composite resin of 0.5mm) was placed unilaterally on the central fossa of the lower first molar for 1 week. The jaw movement and masseter muscle activity were measured by Helkimo index and portable EMG system. The recorded data were obtained before and during day 1, day 2, day 7, and day 14 after insertion of the interference. There was a significant decrease in mandibular border movement and masseter muscle activity immediately after insertion of the interference on day 1. On day 14 the jaw movement and muscle activity were recovered to pre-experimental stage without causing any symptoms. It is apparent that occlusal interferences are associated with short-term clinical symptoms and signs but they won't have specific long-term detrimental effects.