ABSTRACT

The aim of this study was to investigate the Bolton ratio differences between normal occlusion cases and Class I, Class II division 1, Class II division 2 and Class III malocclusion cases and to determine the role of sex differences. The patients were divided into 5 different groups. Class I, Class II division 1, Class II division 2, Class III malocclusions and normal occlusion. Each group had 60 boys and 60 girls. Mesiodistal tooth size measurements of upper and lower teeth were performed on 600 dental casts using a digital caliper. To determine the discrepancy, anterior ratios and total ratios mentioned in Bolton Analysis were calculated. These ratios were compared between different malocclusion and gender groups. The statistical analyses were performed using SPSS for Windows (version 10.0) statistics software. The intergroup comparisons were made using unidirectional variance analysis (ANOVA) and Tukey HSD tests. Lettering method was used in the one by one comparison between different groups. In this study, it was found that there were no differences in tooth dimension ratios between different sex groups in malocclusion cases (Class I, Class II division 1, Class II division 2, Class III malocclusion), but in normal occlusion group, anterior ratio was found to be higher in girls than males. It was observed that there was a significant difference in anterior ratios between Class III and Class II division 1 malocclusions in girls. Statistically significant differences were also observed in total ratios between normal occlusion and Class II division 1 and 2 malocclusion. Since it was a fact that the total and anterior ratio values determined for Turkish population were higher than Bolton's values, it would be better to take these specific values for Turkish people into consideration for treatment planning.