Comparison of Two Scoring Methods for Occlusal Caries Detection

Objective: Our aim was to compare two methods, visuo-tactile and electrical conductance, for detecting occlusal caries in first permanent molars of Venezuelan children. Methods: One hundred fifty-four, 9 to 11 years olds, from Baute Elementary School, Sucre Municipality, Caracas, were examined for caries by visuo-tactile and electrical conductance (EC) methods. Two standardized clinical researchers performed the examinations. One (CM) examined by visuo-tactile means, i.e mirror and probe and Radike DMFS scoring (1972), as modified by Acevedo et al. (2005). The other (MM) utilized a sensitive EC meter we recently developed. Results: Twice as many occlusal lesions were detected by EC than by visuo-tactile means (95.0% vs 42.6%). Diagnostic matrix analysis showed sensitivity and specificity of EC vs the visuo-tactile examination was 0.96 and 0.06, respectively. Positive and negative predictive values were 0.49 and 0.62, respectively. Specificity results appeared too disparate to arise from method error but could be due to differences in detection capability, i.e EC could detect non-cavitated lesions much earlier than visuo-tactile could. To test for this possibility, a second examination was done 9.7 months after the first. DMFS scores increased: 94 new caries lesions developed, of which, 61 (13.7%) were frank cavitations. Previous EC detectable, visuo-tactile undetectable caries lesions were now detectable by visuo-tactile inspection. This decreased the number of false positives and improved method specificity. Evidently, false positives were not due to method error. Conclusion: Our sensitive EC method detects caries lesions very early and when they are very small. The opposite is more characteristic of visuo-tactile caries detection. Hence, lag in caries detection and low specificity are the results expected when EC and traditional visuo-tactile examinations are compared as herein.