|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1996 : ¥200,000 (Direct Cost : ¥200,000)
Fiscal Year 1995 : ¥1,900,000 (Direct Cost : ¥1,900,000)
The purpose of this study was to determine the pathways of the condylar-components of the temporo-mandibular joint in relation to the different stages of tooth eruption. The condylar pathways during protrusion-retrusion, lateral excursion, opening-closing of Hellman's Dental Age stage II A,II C,III A and III C were analyzed using computer-aided diagnostic axiograph (CADIAX) from a total of 20 subjects. The results were as follows :
1. At each stage, the condylar pathway appeared concave at all recorded movements.
2. At Stage II A,the maximum translation value (sMax) during protrusion-retrusion was 9.8 mm, lateral extrusion was 11.5 mm and opening-closing was 13.0 mm. In comparison to the other stages, the maximum translation value of Stage II A was found to be significantly higher than the other stages.
3. The values of maximum rotation (gamma max) for Stage II A was 38.1ﾟ, StageII C was 35.0ﾟ, Stage III A was 33.2ﾟand Stage III C was 31.1ﾟ.
4. For the protrusion-retrusion movements with a Horizontal Condylar Inclination of 5 mm, the analyzed values for Stage II A was 37.3ﾟ, Stage II C was 41.6ﾟ, Stage II A was 46.6ﾟand Stage III C was 46.3ﾟ. Stage II A was found to be significantly lower than the other stages.
5. The magnitude of translation of the condylar movement of Stage II A was small, Sowever, a bigger magnitude of rotation was observed.
6. In the relationship between condylar rotation and translation during opening, a predominant appearance of rotation movement in initial stage were observed for Stages II A and II C ; and translation movement for Stages III A and III C.During the final stage of opening movement, the predominance of rotation movements was observed in all stages.
7. A difference in the translation and rotation movements of the condyle during opening and closing were observed.