Applicability of three tooth size prediction methods for white Brazilians

The objectives of this study were to evaluate the applicability of the methods of Moyers; Tanaka and Johnston; and Bernabé and Flores-Mir to Brazilian individuals and to propose new regression equations using the lower four permanent incisors as predictors for the sum of the widths of the lower permanent canine and premolars. Five hundred dental study casts (250 male and 250 female white patients) were used. The methods of Moyers and Tanaka and Johnston were tested on a sample consisting of 240 female and 223 male patients. The method of Bernabé and Flores-Mir and the new regression equations were based on the complete sample. At the 50th and 75th percentile levels, Moyers' tables tended to underestimate the actual sum of the lower permanent canine and premolars for male and female samples, with statistically significant differences. Although the same statistical significant differences were found when Tanaka and Johnston's and Bernabé and Flores-Mir's methods were used, these differences were not clinically relevant. The new regression equations proposed demonstrate similar correlation and determination coefficients to those found in other studies based on the lower four permanent incisors as predictors. Validating studies (based on similar samples) must be conducted to confirm the applicability and precision of the proposed new regression equations.