A Comparison of Maxillary Arch Form and Dento-Skeletal Patterns in Japanese and Caucasian American Individuals Exhibiting Class II Div. 1 Malocclusions

Abstract

A study was made comparing Japanese and Caucasian American Class II, Div. 1 malocclusions with respect to maxillary arch form and dento-skeletal patterns. For the arch form study, the maxillary casts of twenty Caucasian and eighteen Japanese individuals of comparable ages were evaluated. Dental arch indices were calculated for each individual and the mean values of the two groups were tested for significant difference. The Caucasian arches exhibited a more narrow tapering form than did the Japanese. In the second part of the study, eighteen Japanese and eighteen Caucasian American Class II, Div. 1 malocclusions were evaluated for differences in dento-facial architecture. Downs' radiographic cephalometric analytical procedure was used. Mental prominence was also measured using a technic which was described. It was found that the facial plan angle and mandibular plane angle in the Japanese group was more obtuse. The mental prominence in the Caucasian group was larger than in the Japanese group.