Aim: Orthodontic need assessment is instrumental for dental treatment planning. The objective of this examination was to evaluate the orthodontic treatment need of students in Shiraz, Iran, using the Dental Aesthetic Index (DAI) and to assess the relationship between DAI and sociodemographic variables. Methods: Using random cluster sampling, 1,818 pupils (965 male and 853 female) 14 to 18 years of age without any history of orthodontic treatment were selected. Information was gathered using a questionnaire, including demographics such as sex, family size, and parents’ education. Orthodontic assessments were performed by two orthodontists over 2 months. The data were analyzed with chi-square and t tests. Results: Many of the subjects (48.3%) had no need for orthodontic treatment. About one-fifth of the population (21%) had intense-to-disabling malocclusions, and 8.4% had disabling malocclusion with compulsory treatment needs. The study showed a close relationship between sex and malocclusion. Conclusion: The study showed that Iranian youth in Shiraz had better dental appearances and less orthodontic treatment need than some populations (Japanese, Caucasian and Native Americans, and Caucasian Australians) but worse than Chinese, Spanish, and Nigerian populations. It might be possible to relate the difference to genetics, cultural differences, and growth. World J Orthod 2010;11:e19–e25.
Key words: DAI (Dental Aesthetic Index), orthodontic treatment need, disabling malocclusion