LAUSR

Purpose An evaluation of the reliability and validity of two child oral health-related quality of life (COHRQoL) measures among Australian Aboriginal children who participated in a randomised trial was undertaken. Methods Study participants completed the Early Childhood Oral Health Impact Scale (ECOHIS) and the Caries Impacts and Experiences Questionnaire for Children (CARIES-QC). The questionnaires were completed a second time to test the scales’ test–retest reliability. Internal consistency, convergent and discriminant validity were evaluated through Cronbach’s alpha, correlation of the scale scores with the global oral health evaluation, and comparison of scale scores among children with varying levels of caries experience, respectively. Results Worse COHRQoL was reported by parents who rated their child’s oral health as poor and by children who rated their teeth as being a lot of problem. Cronbach’s alpha for the child impact section (CIS), family impact section (FIS), total ECOHIS score and the total CARIES-QC scale were 0.88, 0.81, 0.91 and 0.84, respectively. Spearman’s correlations between scale scores and global oral health ratings of the CIS, FIS, total ECOHIS and the CARIES-QC were 0.42, 0.34, 0.45 and 0.70, respectively, p  < 0.001. The Kruskal–Wallis test of scale scores with grouped caries experience was statistically significant, p  < 0.005. Test–retest reliabilities for the ECOHIS were CIS ICC = 0.91, FIS ICC = 0.89, total ECOHIS ICC = 0.93 and for the CARIES-QC, ICC = 0.61. Conclusions Both the ECOHIS and the CARIES-QC were reliable and valid scales for use among an Australian Aboriginal population for assessing COHRQoL of preschool children. Trial registration ACTRN12616001537448, date of registration—08 November 2016