Anterior and Overall Bolton ratios among Orthodontic Patients with Different Malocclusions

The aim of this study was to determine Bolton ratios in the Iranian orthodontically treated population of different malocclusions and compare these values among malocclusion groups and with Bolton reference values.

Bolton ratios of 210 subjects were investigated in three groups of Class I, II, and III skeletal patterns. The measurement of mesiodistal width of teeth was made on post-treatment dental models using a digital caliper. One-way analysis of variance and one-sample t-test were used to compare obtained anterior values and overall ratios among studied groups and with reference values, respectively. P-value<0.05 was considered as significant.

The mean values of anterior ratio in total subjects were 76.77, and in the Class I skeletal pattern group was 76.51, which were significantly different from the reference value (p-value < 0.05). However, the differences in the mean anterior ratios of Class II and III groups and the mean overall ratios of three studied groups with reference values were not statistically significant. Furthermore, there was no significant difference between the anterior and overall Bolton ratios of the three studied groups (p-value>0.05).

Since the obtained Bolton ratios in Class II and III groups were not significantly different from reference values, these values are also applicable for mild skeletal malocclusions. However, the difference in mean anterior ratios of the total 210 subjects and Class I group with Bolton reference values could be caused by racial differences or several factors related to orthodontic treatment, which can be investigated in subsequent studies.