March 2007

Dental anxiety assessment can be achieved by using brief multi-item scales. Corah’s Dental Anxiety Scale has been used extensively since the 1970s. However the scale has some flaws which led to the design of the Modified Dental Anxiety Scale incorporating some minor but important improvements. To enable comparison between studies who have adopted one but not both scales a conversion algorithm was required. Objective: To produce regression equations and tables to enable researchers to convert derived scores from one scale to another. Basic research design: Cross-sectional survey. Clinical setting: 18 dental practices in Northern Ireland. Participants: Patients (n=1,028) were invited to participate. Main Outcome measures: Corah and Modified Dental Anxiety Scales Results: Twenty four patients refused (response rate 98%) providing 1,004 patients for analysis. Mean scores for both scales were close to those reported elsewhere. The correlation between the two scales was high (r=0.89). Regression equation and summary tables presented for conversion purposes. Conclusions: More accurate estimates of scale scores can be derived with this procedure than simple prorating. Key words: Conversion tables, Corah, dental anxiety scales, Modified, psychometrics.