Ranking dental aesthetics and thresholds of treatment need: a comparison between patients, parents, and dentists

The aims of the present study were to compare rankings of dental aesthetics and the threshold at which orthodontic treatment would be sought among patients, parents, and dentists. A prospective cross-sectional study was designed to address these aims. The study sample comprised 100 patients and parents and 23 dental specialists. The patients were equally divided between males and females and their mean age was 14.7 years (standard deviation 2.3 years). The aesthetic component (AC) of the Index of Orthodontic Treatment Need (IOTN) represented impairment of dental aesthetics. The 10 numbered photographs of the AC were cut into equal-sized rectangles and subjects were asked to arrange them from 'the one that looks best' to 'the one that looks worst'. The subjects were then presented with the 10 photographs of AC in sequence and asked to identify the cut-off point between 'teeth that need orthodontic treatment' and 'no treatment'. Statistical analysis was undertaken with a Mann-Whitney test. The results showed that median rankings of dental aesthetics were similar among the three groups (P > 0.05). The median ranking of photographs 1, 2, 3, 4, and 10 were identical to the AC of IOTN. The photographs representing IOTN AC 7 and 8 were allocated the same median rank of 7 and AC 5 and 9 were allocated corresponding median ranks of 6 and 8, respectively. There were no significant differences in median cut-off points for treatment need among the three groups of subjects (P > 0.05), indicating that the mean threshold at which treatment would be sought was AC 4.