The present study assesses the validity and reproducibility of two occlusal indices for epidemiological studies--the Dental Aesthetic Index (DAI) and the Dental Health Component of the Index of Orthodontic Treatment Need (DHC-IOTN) for the identification of orthodontic treatment needs. The total of 131 study models was examined by an examiner (orthodontic specialist) for the determination of the DAI and DHC-IOTN. Thirty days later, further assessment was performed to determine the reproducibility. The duration of each exam was measured in seconds with a stopwatch. The indices were compared by a panel of three experts in orthodontics to evaluate validity. The intra-examiner reliability evaluation resulted in an intraclass correlation coefficient of 0.89 for the DAI (95% CI = 0.64 to 1.0) and 0.87 for the DHC-IOTN (95% CI = 0.56 to 0.96). The time spent on the evaluation of the DHC-IOTN was less than the time spent on that of the DAI (P < 0.001). The accuracy of the indices, as reflected by the area under the receiver-operating characteristic curve, was 61% for the DAI (95% CI = 51 to 70; p = 0.037) and 67% for the DHC-IOTN (95% CI = 58 to 77; p = 0.001). Both indices presented good reproducibility and validity.
Keywords: epidemiology; indexes; orthodontics.