Assessment of the Index of Dental Anxiety and Fear (IDAF-4C⁺)

The Index of Dental Anxiety and Fear (IDAF-4C⁺) was developed to address the theoretical shortcomings of existing dental fear scales and provide a more practical alternative to some lengthy scales. The IDAF-4C⁺ comprises a modular design with three sections assessing the four components dental anxiety and fear (IDAF-4C), dental phobia (IDAF-P) and anxiety-invoking stimuli (IDAF-S). Objectives: To assess reliability and validity information on the IDAF-4C⁺ in a population sample of Australian adults and compare the IDAF-4C with Corah's Dental Anxiety Scale (DAS). Methods: 1,084 Australian adults completed a mailed questionnaire. The internal consistency of the IDAF-4C was assessed using Cronbach's alpha and test-retest reliability at 4-months was assessed for all modules. Validity information on the IDAF-P and IDAF-S was obtained by analysing correlations between phobia diagnoses and stimulus module items with dental fear and avoidance. The validity and screening accuracy of the IDAF-4C was compared to that of the DAS. Results: The IDAF-4C showed a high internal consistency (a = 0.94) and good test-retest reliability at four months (r = 0.81). Test-retest of the IDAF-S items ranged from 0.55 to 0.73 and was 0.68 for the least stringent dental phobia diagnosis, but not significant for a strict DSM-IV based diagnosis. IDAF-S items were all significantly associated with dental fear. The IDAF-4C was highly correlated with the DAS (r = 0.85). Both fear scales were significantly associated with reduced dental visiting, usual reason for visiting, avoidance due to fear, and with having visited a dentist and visit rating at 4 month follow-up. The IDAF-4C better predicted dental phobia diagnosis and had higher sensitivity and specificity than the DAS. Conclusions: The IDAF-4C⁺ is a valid measure for assessing dental anxiety and fear, dental phobia and potentially anxiety-inducing dental stimuli in an adult population. Funded by the Australian Dental Research Foundation.