Applicability of regression equation using widths of mandibular permanent first molars and incisors as a predictor of widths of mandibular canines and premolars in contemporary Indian population

Background: Predicting the size of unerupted teeth during the mixed dentition period is a critical factor in managing the developing occlusion. Different studies found that the combined width of only the four mandibular permanent incisors is not a good predictor of the sum of unerupted mandibular permanent canines and premolars (SPCP). In 2007, Melgaço et al. developed a new method for SPCP by measuring the sum of the mandibular first permanent molars and four mandibular permanent incisors (SMI). Aim: It was aimed to evaluate the accuracy of this new method in comparison with Moyers′ mixed dentition analysis table in contemporary Indian population. Settings and Design: Sixty boys and 60 girls from Gandhinagar district (age ranged from 12 to 14 years) were included. Materials and Methods: The mesiodistal crown widths of all fully erupted teeth were measured with digital vernier callipers and the odontometric values obtained were then subjected to statistical and linear regression analysis. Results: Student′s unpaired t-test gave statistically significant difference between the original values of teeth and the values obtained by Melgaço′s prediction equation as well as Moyers′ mixed dentition analysis table (P < 0.001). High values of correlation (r = 0.77) and determination coefficients (r2 = 0.59) were found while considering Melgaço′s method. Also, no statistically significant difference was found between the tooth sizes of males and females. Conclusion: From this study, it can be evaluated that Melgaço′s method gives better prediction and a simplified equation Y = 0.925X can be suggested for the present population.