Social acceptability of occlusal conditions and fixed orthodontic treatment

The Dental Aesthetic Index (DAI) was developed as an indicator of social acceptability of occlusal conditions (SASOC)to prioritise treament. However, it may also be an outcome measure of how SASOC changes with fixed orthodontic treatment(FOT). Objective: to examine SASOC in adulthood by history of FOT. Methods: In 1988/89 3709 13 year olds at school dental clinics in South Australia participated in a study of occlusal conditions. Among data collected were 10 DAI traits, allowing calculation of a DAI 13 score. Information on subsequent FOT was collected by questionnaire across the next two years. In 2006 subjects were re-approached at 30 years old. Of 1859 subjects traced, 632 responded to a questionnaire and 441 underwent an examination. A DAI 30 score was calculated. Data were matched for 427 subjects. The association between DAI 13 and subsequent FOT and DAI 30 and a history of FOT are analysed. Results: Mean DAI 13 was 28.0. 15.7% had a DAI 13 of 36+(lower SASOC). Of those with a DAI 13 36 + (lower SASOC) 62.3% had FOT, compared with 30.1% for those with a DAI 13 <36 (higher SASOC) (Chi sq, p<0.001). DAI 13 among those without subsequent FOT was 26.4 and with FOT was 31.1 (t-test, p<0.001) and change in DAI (DAI 13 – DAI 30) was 3.7 and 8.8 respectively. Multivariate modelling revealed DAI 30 was significantly associated with DAI 13 and the interaction between DAI 13 and FOT, indicating that FOT was associated with lower DAI 30, but only among those with higher DAI 13. Conclusion: DAI 13 had a positive association with subsequent FOT. However, most students receiving FOT had a low baseline DAI 13. FOT had no effect on DAI 30 for those with a low DAI 13, but did reduce SASOC among those with a high DAI 13.