Repeatability for secondary caries detection: Diagnodent and Visual Examination

Objective: This investigation assessed the repeatability of DIAGNOdent (KaVo, Biberach, Germany) and a visual examination in the detection of secondary caries. Methods: Following approval by the IUMC Institutional Review Board, 218 amalgam and resin restorations were placed in deciduous molars of 90 children. Between 6-15 sites on the margin of each restoration were examined independently by two examiners. Repeatability was analyzed by visit for each site on a tooth. A paired t-test tested the hypothesis of a zero mean difference between repeated measures. ICC was used to judge the amount of variation between repeated measures relative to the total variation. For DIAGNOdent, each site was classified as carious if the value was ³ 15 and a kappa value was estimated. Since the visual examination is an ordinal scale, weighted kappa was used to assess the strength of agreement between repeated measurements. Results: The paired t-tests indicated that for both visits 1 and 3, the mean difference between repeated DIAGNOdent measurements was significantly different from zero. The ICC at visit 1 was low at 0.62, indicating that the variability between repeated measurements accounted for 38% of the total variation. In addition, in this study DIAGNodent measurements were used to classify sites as either carious or sound. Using the scale from Landis and Koch, the kappa at visit 1 indicated substantial agreement in classification between repetitions. At visit 3, the kappa indicated almost perfect agreement. At visit 1, for the visual examination, the weighed kappa was 0.29 indicating only fair agreement but the ICC was 0.41 indicating that most of the variability came from between repetitions Conclusions: Neither diagnostic technique showed good inter-examiner repeatability over the entire range of values. However, when DIAGNOdent was dichotomized into carious and sound, the inter-examiner agreement was consistently high. Supported by NIH Grant PO1DE13540-03