Adding Faces to the MCDAS: a Study of Reliability

Introduction: The Modified Child Dental Anxiety Scale (MCDAS) is a measure of dental anxiety in children. It has an 8-question format, with a numeric rating scale ranging from 1 to 5. (Wong et al Psychological Reports: 1998: 83; 1179-86) Objectives: To assess the reliability of a version of the MCDAS modified by the addition of a face rating scale to the original numeric format (MCDASf). Methods: A non-random convenience sample of all children aged 9-10 years-old was drawn from 4 primary schools in the greater Belfast, half of the children received the MCDAS on the first administration, and the MCDASf 2 weeks later. The other half of the children received the MCDASf at the first administration. A second administration of the MCDASf was completed 17 weeks later. Results: Complete data was obtained for 85% (237) of the sample. The correlation between the total mean scores on the MCDAS and the MCDASf was highly significant (r=0.79, p<0.001). The internal consistencies (Cronbach alphas) of the first administration were 0.78.There was no significant difference between the total mean scores on the MCDAS or MCDASf when the MCDASf was administered first (F[1,235]=1.54:P=0.69), or when the MCDAS was administered first (F[1,235]=2.86:P=0.92). Complete data was obtained for 88% (241) for test retest reliability. The total mean score for MCDASf was significantly higher at time 1 (19.86 (19.06,20.67)) than at time 2 (19.05 (18.18,19.92), t=2.18, p=0.03). Intra-class correlations ranged from 0.57 to 0.80. Conclusion: This study confirms the reliability of a faces version of the MCDAS and indicated adequate performance as a self-report measure of dental anxiety.