Validation of the Chinese version of the Malocclusion Impact Questionnaire (MIQ)

To translate and cross-culturally adapt the Malocclusion Impact Questionnaire (MIQ) into Chinese and to assess the psychometric properties of the Chinese version of the MIQ (MIQ/C) for use among adolescents with malocclusion in China. First, the MIQ/C was developed according to international guidelines. Then, the MIQ/C was filled out by 536 adolescents between 10 and 16 years of age. This study used exploratory factor analysis (EFA), confirmatory factor analysis (CFA), convergent validity, internal consistency, and test-retest reliability to evaluate the psychometric properties of the MIQ/C. Following EFA, three domains were extracted, accounting for 65.950% of the total variance. The CFA results showed that the fit indices of each factor in the three-factor model all reached the standard (chi-square/DF = 2.591, GFI = 0.919, TLI = 0.926, CFI = 0.928, RMSEA = 0.076). The scale evidenced a good relationship with the two global questions, indicating good convergent validity. The Cronbach alpha value and the intraclass correlation coefficients (ICC) value of the MIQ/C were 0.929 and 0.893, respectively. The MIQ/C demonstrated good reliability and validity and can be further studied and applied in Chinese adolescents with malocclusion. The MIQ/C can be applied to assess the psychosocial impact of malocclusion among Chinese adolescents.