OBJECTIVES: A cross-sectional study was conducted to determine the level of agreement between the Dental Aesthetic Index (DAI) and the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN). METHODS: DAI and AC scores were recorded in 728 subjects (340 females and 388 males, aged 11-20 years). The percentage of subjects needing treatment and the different treatment categories for the DAI and AC were gender compared. Spearman's rank correlation coefficient (rho) was used to explore the relationship between the DAI and AC scores. Observer determined and Kappa statistics were used to analyse the diagnostic level of agreement between the DAI and AC, sorted into 'yes' or 'no' categories of orthodontic treatment need. RESULTS: According to the DAI and AC, 21.8 and 10.9% of subjects were in need of treatment, respectively. Significant positive correlations existed between the DAI and AC scores (rho = 0.795). The DAI had a lower treatment need threshold compared with the AC. The Kappa statistics and percentage agreement between the DAI and AC was 0.55 (95% CI: 0.46-0.63) and 87.6%, respectively. CONCLUSION: The DAI and AC showed strong association. However, only a moderate level of diagnostic agreement was identified (12.4% difference in observed percentage agreement) which highlights the need for a unified and universal orthodontic index for consideration when interpreting, comparing, or quantifying treatment needs.
OBJECTIVES: A cross-sectional study was conducted to determine the level of agreement between the Dental Aesthetic Index (DAI) and the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN). METHODS: DAI and AC scores were recorded in 728 subjects (340 females and 388 males, aged 11-20 years). The percentage of subjects needing treatment and the different treatment categories for the DAI and AC were gender compared. Spearman's rank correlation coefficient (rho) was used to explore the relationship between the DAI and AC scores. Observer determined and Kappa statistics were used to analyse the diagnostic level of agreement between the DAI and AC, sorted into 'yes' or 'no' categories of orthodontic treatment need. RESULTS: According to the DAI and AC, 21.8 and 10.9% of subjects were in need of treatment, respectively. Significant positive correlations existed between the DAI and AC scores (rho = 0.795). The DAI had a lower treatment need threshold compared with the AC. The Kappa statistics and percentage agreement between the DAI and AC was 0.55 (95% CI: 0.46-0.63) and 87.6%, respectively. CONCLUSION: The DAI and AC showed strong association. However, only a moderate level of diagnostic agreement was identified (12.4% difference in observed percentage agreement) which highlights the need for a unified and universal orthodontic index for consideration when interpreting, comparing, or quantifying treatment needs.