1 Assistant Professor, Department of orthodontic, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
2 Associate Professor, Department of orthodontic, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Aim: A high percentage of the problems in finishing phase are due to tooth size imbalances that can be diagnosed in initial stages of treatment. The purpose of present study is to evaluate the frequency of anterior tooth size discrepancies by Bolton Analysis among class I, II and III malocclusions.
Materials and methods: The mesio-distal widths of six anterior teeth in 90 paired casts of patients (class I, II, and III), who were selected non-randomly, were measured. Chi-square test was performed to compare the frequency of anterior tooth size discrepancies between the three malocclusion groups. Analysis of variance was used to compare the mean anterior Bolton ratios as a function of skeletal anterior-posterior malocclusions and both genders. Mean mesio-distal width of six anterior teeth were compared by Analysis of variance in 3 skeletal malocclusion groups. Statistical differences were determined at the 95% confidence level.
Results: Discrepancy was greater in class I and III than in class II. No sex difference was shown to exist in Bolton anterior ratio. mesio-distal width of upper laterals had greater variation coefficient.
Conclusion: Difference of mean anterior tooth size discrepancies among three skeletal class I, II and III malocclusions were not statistically significant.