Bolton tooth size discrepancies in skeletal Class I individuals presenting with different dental angle classifications.

The objective of this study was to investigate the frequency and association of Bolton tooth size discrepancies with dental discrepancies. Forty-eight skeletal Class I, 60 Class II, and 44 Class III subjects with similar skeletal characteristics were included in this study. Analysis of variance was performed to compare the mean ratios of Bolton analysis as a function of the Angle classification and sex. To determine the prevalence of tooth size imbalances among the three groups of occlusions and the two sexes, chi-square tests were performed. To determine the correlation of tooth size imbalances with certain dental characteristics, Pearson's correlation coefficients were calculated. No statistically significant differences were determined for the prevalence of tooth size discrepancies and the mean values of Bolton's anterior and overall ratios among the occlusal groups and sexes. Bolton's anterior ratio discrepancies had significant correlations with midline shifts (P < .05) in Angle Class I cases, with U1-SN angle (P < .01) in Angle Class II cases, and with L1-APog distance (P < .05) in Angle Class III cases. Bolton discrepancies related to overall ratio had significant correlations with overjet (P < .05) in Class I cases, with overbite (P < .05) and U1-SN angle (P < .01) in Class II cases, and with IMPA (P < .01) in Class III cases. A high prevalence of tooth size discrepancies in an orthodontic patient population and the statistically significant correlation of some of these with some dental characteristics suggest that the measurement of interarch tooth size ratios might be clinically beneficial for treatment outcomes.