Cross-cultural adaptation and validation of the Arabic version of the Malocclusion Impact Scale for Early Childhood (MIS-EC/Ar)

BACKGROUND: Malocclusion is a highly prevalent oral disease in children. It could detrimentally affect their oral health-related quality of life (OHR-QoL). The Malocclusion Impact Scale for Early Childhood (MIS-EC) is a newly developed scale for the assessment of OHR-QoL in this population aged 3-5 years-old. The aim of this study is to translate and validate an Arabic version of the MIS-EC scale (MIS-EC/Ar). MATERIALS AND METHODS: Translation and cross-cultural adaptation of the MIS-EC/Ar scale were performed conforming to relevant WHO guidelines. A sample of mothers/caregivers of children aged between 3 and 6 years was recruited (n = 236). Clinical examination of children and assessment of malocclusion were performed before taking MIS-EC/Ar. The internal consistency was assessed using Cronbach's alpha. Test-retest reliability performed after two weeks (n = 30) employed intraclass correlation coefficient (ICC). Construct validity, including convergent, discriminant, and structural validity, was evaluated in addition to criterion validity. RESULTS: MIS-EC/Ar showed good internal consistency (standardized Cronbach's alpha = 0.797) and excellent test-retest reliability (ICC = 0.929, 95% CI 0.884-0.962). Convergent validity, Spearman correlation coefficients for the MIS-EC/Ar total score with the overall oral health question, was limited (r = 0.159, P < 0.05). Discriminant validity was significant (p < 0.05). Criterion validity was fair (r = 0.298, p = 0.01). Exploratory factor analysis suggested a reduced scale of six items. CONCLUSIONS: The MIS-EC/Ar is a reliable instrument with good discriminant validity for assessing malocclusion impact on preschool children's OHR-QoL. Limited convergent validity and altered factor structure suggest cultural adaptation effects.