The purpose of this study is to establish the criteria for the diagnosis of the positional relationships between condyle and articular fossa of the patients with so-called TMJ Arthrosls.
Three-dimensional measurement and reconstruction of the TMJ bony space were made using a simultaneous lateral tomography and computer.
Eighty patients with TMJ Arthrosis and eleven persons of individual normal occlusion without subjective and objective symptom were put into this study. Tomographic examination was performed with the teeth in the intercuspal position.
Condyle-Fossa Distance (CFD) was determined by the shortest distance between one point matrix of condyle and another point matrix of fossa.
Mean value and standard deviation of three-dimensional measurement was 2.02mm±0.23mm to the actual distance of 2.11mm. The change of distribution of CFD frequency by projective angle was negligible.
The following analyses and investigation were performed with special reference to the CFD of both sides.
1) The patterns of bilateral distributions of CFD frequency were classified in 6 types.
2) The correlation between bilateral distributions of CFD frequency and abnormal radiographic finding of bone components was investigated.
3) The correlation between bilateral distributions of CFD frequency and clinical symptoms (Grade-1. 2. 3.) was investigated.
From these studies, following results were obtained:
1. No CFD less than 1.0mm was found in the control group and bilateral distributions of CFD frequency were corresponding in 9 of 11 cases.
2. CFD less than 1.0mm and/or distributions of CFD frequency not corresponding bilaterally were found in 63 of 80 cases (78.8%) in the patients group.
3. The cases in which distributions of CFD frequency were not corresponding bilaterally revealed radiographic bone changes at a high rate (68.0%).
4. In the groups those CFD of unaffected side was smaller than that of affected side (type 3&6), limitation of opening mouth with pain (Grade-3) was the most predominant clinical symptom (18/35, 51.4%).
From these results, it was suggested that distributions of bilateral CFD frequency were correlated with radiographic bone changes and clinical symptoms.
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