The purpose of this study is to apply 3-dimensional image to mandibular movement data, and to discuss the clinical utility of this information. The subject was a 26-year-old female of volunteer who has no missing teeth and no morbid findings in clinical examinations. Prior to taking the computerized tomography (CT), mandibular movements were measured using POLARIS, an optical position measurement device. The skull, mandibular and clutches were reconstructed into a 3-dimensional image from the obtained CT data. The relationship markers and anatomic structures were computed on CT imaging. The movements in each region of the anatomic structures were calculated using the data from the CT and POLARIS. The 3-dimensional imaging on the computer monitor was synchronized with the human movement by a real-time imaging system. The following fundamental jaw movements were mainly investigated: opening and closing motions, border jaw movements in the sagittal plane and lateral excursion movements. In intercuspal position and all sorts of mandibular movements, we could observe various condyle movements including the relationship of the position between the condyle and the temporal bone. Therefore this information can be applied to predict the regions of guide and loading in each movement. There is a possibility that it uncovers unprecedented movements and relationships between movements and anatomic structures in patients with osteoarthritis. By using this system, we could acquire much more information than by previous analysis of mandibular movements. It was suggested that 4-dimensional analysis would be useful in studying the pathogenesis of disease and convalescence in Temporomandibular disorders.
