The Modified Dental Anxiety Scale: validation and United Kingdom norms.

The Corah Dental Anxiety Scale (CDAS) has been used extensively in epidemiology and clinical research. It is brief and is claimed to have good psychometric properties. However, it does not include any reference to local anaesthetic injections, a major focus of anxiety for many. Also, the multiple choice answers for three of the four questions are not clearly in order of severity of anxiety as the CDAS intends. The answers differ among the questions thus making them difficult to compare. They include descriptions of physiological reactions and anxiety, confusing two loosely related components of the experience. The Modified Dental Anxiety Scale (MDAS) described, added a question on anxiety about oral injections. New multiple choice answers, in clear order of anxiety and the same for each question, were provided. Twenty five dental personnel all confirmed independently the order of the multiple choice answers for the MDAS. They disagreed among themselves however, about the appropriate sequence for the answers denoting intermediate anxiety in the CDAS. Therefore the CDAS, unlike the MDAS, can provide meaningful measures only of extremely high or extremely low dental anxiety. Of 1392 subjects tested, 13 per cent expressed extreme anxiety about injections on the MDAS but were only 'fairly' or less anxious about drilling. Thus, the CDAS, unlike the MDAS, must overlook subjects very afraid of injections only. Data confirm the high reliability and validity of the MDAS and provide norms for phobic and nonphobic subjects.