Size of the mandibular jaw angle related to age, tooth retention and gender.

The size of the gonial angle was measured in cephalograms of 431 adults attending the Department of Prosthodontics, School of Dentistry, University of Bergen, Norway. The purpose of the work was to conduct a study of the variables often related to the development of the size of the gonial angle, i.e. age, degree of tooth retention, and gender. Descriptive data showed that the edentulous participants had the largest mean angle, the participants in possession of all teeth had the smallest angle, and the partially dentate participants had a jaw angle size between that of the aforementioned groups. Preliminary results of the analysis (ANOVA) showed that the number of teeth had a decisive influence on the size of the gonial angle. The correlation coefficients between size of the gonial angle and age showed that age explained approximately 8-16% of the variation of the angle through its relation with age. Sex differences in age and size of the gonial angle were not statistically significant in any of the three tooth retention categories. Future multiple regression analysis may explain a greater part of the variation of the angle if the analysis is carried out in separate age groups of the three categories.