Applicability of the Moyers mixed dentition probability tables and new prediction aids for a contemporary population in India.

Introduction: The Moyers mixed dentition space analysis method is among the most commonly used in clinical practice for detecting tooth size-arch length discrepancies. In view of reported secular trends, racial, and sex differences in tooth sizes, the purposes of this study were to evaluate the applicability of Moyers probability tables in a contemporary orthodontic population of India and to formulate more accurate mixed dentition prediction aids.

Methods: Odontometric data were collected from 300 male and 300 female subjects of Indian descent, who had fully erupted mandibular permanent incisors and maxillary and mandibular canines and premolars. We measured the mesiodistal crown widths with vernier scale dial calipers. The odontometric values obtained were then subjected to statistical and linear regression analysis.

Results: All tooth groups showed significant differences (P <0.001) between mesiodistal widths of male and female subjects. Regression equations for the maxillary arch (males, Y = 7.15 + 0.67X; females, Y = 7.44 + 0.65X) and the mandibular arch (males, Y = 5.55 + 0.71X; females, Y = 6.15 + 0.67X) were used to develop new probability tables on the Moyers pattern. Significant differences (P <0.05) were found between our predicted widths and the Moyers tables at almost all percentile levels, including the recommended 75% and 50% levels.

Conclusions: We believe that these new prediction aids could be considered for a more precise mixed dentition space analysis in Indian children.