Study of Occlusal Contact Area by Occlusal Adjustment: 3. Morphological Analysis of Occlusal Contact Area in the Lateral Excursions

morphological analysis of premature contact area in the lateral excursions. The subjects were staffmembers of the Josai Dental University, PDI Saitama Dental Clinic who had normal occlusal function in clinically. The measurements were made using the Gothic Arch Tracer and the outside marking system which fixed in the dental arch by conforming to Nakao's method and concerning the measurement of the OCA and LG 1° conforming to Miyata's method and the study on the form of contact area, carried out by new software on a personal computer. The results were as follows; 1. In the changing of OCA on lateral excursions, almost all 1st. and 2nd. molars gradually showed decrease for a short period (type 1), but 1st. and 2nd. premolars showed increase (type 2) or begin with a decrease and after that increase (type 3) for a short period. In cuspid rather showed type 2, 3 and no big changing (type 5). 2. In the changing of OCA on lateral excursions, almost all 1st. and 2nd. molars showed type 1, but 1st. and 2nd. premolars showed much of type 2, 5. 3. In the obserbing form of contact area, premolars showed a tendency of changing from the level to the circle form for a short period, but in cuspid showed a tendency of changing to an increasing form.