Predicting handicapping malocclusion using the Dental Aesthetic Index (DAI)

The Dental Aesthetic Index (DAI) is an orthodontic index based on socially defined aesthetic standards. The DAI is useful in both epidemiological surveys to identify unmet need for orthodontic treatment as shown by its use by WHO in ICS-II and as a screening device to determine priority for subsidised orthodontic treatment. The purpose of this study was to determine a decision point on the DAI scale that predicts the clinical judgments of orthodontists in separating handicapping from non-handicapping malocclusion. Orthodontists' decisions were available on a sample of 1306 models representing untreated occlusions found in half a million children. DAI scores were calculated for each model. By correlating orthodontists' decisions with DAI scores a cut-off point was established. Agreements between DAI scores and orthodontists' decisions were best at the 86th percentile on the DAI scale. The DAI score of 36 at the 86th percentile yielded an 88 per cent agreement, a specificity of 93 per cent and a sensitivity of 54 per cent. Cases with scores of 36 and higher would be considered handicapping according to the DAI.