Evaluation of Accuracy of Tanaka-Johnston Mixed Dentition Analysis in North Karnataka Population: A Cross-Sectional Study

Objectives: Estimating the mesiodistal dimensions of unerupted canines and premolars in early mixed dentition is a critical tool in space management. According to previous studies, tooth size varies by ethnicity which could affect diagnosis and treatment planning. The aim of the study was to know whether the Tanaka-Johnston method is valid for the North Karnataka population. Materials and Methods: A total of 4,600 school children (2,300 boys and 2,300 girls) (age 11-16 years) with no craniofacial skeletal abnormalities, with no history of orthodontic and orthopedic treatment or maxillofacial surgeries, from 2013 June to 2019 June were taken for mixed dentition analysis by the Tanaka-Johnston method. Pearson correlation test was used to identify the correlation between various variables. Results: The findings revealed a sexual dimorphism in the widths of canine and premolar widths in the maxillary and mandibular teeth. A statistically significant difference was found between the width of the sum of incisor widths and the actual widths of canine and premolars for maxillary and mandibular arches, regardless of gender. Conclusion: The Tanaka-Johnston analysis was not precise enough to be used for the North Karnataka population in its original form, so new regression equations were developed.