Intention to Prescribe Bitewing Radiographs by Dental Students

Methods: Two curriculum years of fourth-year dental students (n=245) reported their opinion on the optimal frequency of prescribing bitewing radiographs for a scenario patient. We used multivariate regression to analyse association between radiographic prescribing and both decision-making (11) and attitude to uncertainty variables (14). Using visual analogue scales students reported their perception of the prevalence of caries and their utilities for false positive (UFP) and true positive (UTP) treatment outcomes (on a scale between best [UTN] and worst [UFN] outcomes). Diagnostic accuracy (ROCAz) was calculated for radiographs of teeth with either micro-radiographic dentine caries (45) or sound surfaces (60). Using Likert scales students reported their attitudes to uncertainty.

Results: The students valued UFP at mean: 0.33 (SD 0.25) and UTP treatment outcomes at 0.80 (SD 0.18) (P=0.000). Mean subjective prevalence was 0.21 (SD 0.16) whilst diagnostic accuracy was ROCAz 0.89 (SD 0.10). The mean frequency of prescribing radiographs was 26 monthly (SD 9 months), which depended on the chance of toothache from dentine caries after 5 years (P=0.04), perceived prevalence of caries (P=0.023), chance of lesion progression (P=0.000), restorative treatment criterion (P=0.028) and diagnostic accuracy ROCAz (P=0.06).

Conclusions: Only four out of 11 formal decision-making variables played a statistically significant role in the intention to prescribe radiographs. Three of these variables concerned subjective estimates of risks not yet formally taught in the curriculum indicating a need to devote attention to evidence based probabilities involved in diagnosis and decision making.