A comparison of radiographic occlusal and approximal caries diagnoses madeby 240 dentists

Radiographs of occlusal (n = 20) and approximal (n = 24) surfaces of extrac ted teeth were examined by 240 dentists before participating in continuing education courses dealing with caries diagnosis and treatment decisions. Th e radiographic caries diagnoses were treated in accordance with the receive r operating characteristic (ROC) technique, in which the area beneath the R OC curve (A(g) value) indicates the quality of the observations. The freque ncies of false positives made in dentin radiographically were higher for ap proximal (20.7%) than for occlusal caries (12.3%). The quality of pooled ra diographic diagnoses of occlusal dentin lesions for all observers was signi ficantly better than diagnoses of approximal caries in dentin. A statistica lly significant relationship between the observer's qualities of diagnosis of caries on approximal and occlusal surfaces (P = 0.045) was found. For di agnosis of dentin caries on approximal surfaces the mean Cohen kappa was 0. 74 (standard deviation (s), 0.12; range, 0.39-0.95), and the corresponding values for occlusal surfaces were 0.70 (s, 0.14; range, 0.25-0.98). In the material under study the dentists were at least as good at diagnosing denti n caries occlusally as approximally. To avoid overtreatment, the observer's diagnostic threshold should ideally be adjusted towards strict criteria wh en a positive diagnosis is synonymous with a filling. The diagnostic thresh olds were stricter in diagnosing occlusal surfaces than for approximal surf aces, indicating a more optimal strategy among dentists while diagnosing oc clusal dentin lesions in a population with low caries prevalence.