Orthodontic treatment needs: comparison of two indices

The Index of Orthodontic Treatment Needs (IOTN) and the Dental Aesthetic Index (DAI) were developed and both claimed to contain the aesthetic and dental components in their criteria of assessing malocclusion. This study was undertaken to assess the reliability of these two indices in assessing orthodontic treatment needs. The indices were applied to 120 pre-treatment study models selected from orthodontic patient records treated at the Department of Orthodontics, University of North Carolina, United States of America. The sample consisted of 60 African-Americans (Black) and 60 American Caucasians (White), age ranged from 12 to 16 years (Mean 13.8). The results showed that the IOTN and the DAI were highly correlated and highly associated statistically (p < 0.0001). The findings of this study indicated that the two indices could be used consistently to identify orthodontic treatment needs in different ethnic groups and are capable of classifying the subjects according to their malocclusion severity for those subjects eligible for treatment in fund constrained situation.