Efficacy of a dip slide test for mutans streptococci in caries risk assessment

The aim of this study was to evaluate the efficacy of a dip slide test for mutans streptococci in caries risk assessment, when the microbiological results were compared to well-defined clinical criteria (DCC) for caries risk, clinically measured through high and low caries activity. Eighty-one volunteers from the 6th to 8th grades from public schools of Piracicaba, Sao Paulo, Brazil, were evaluated for dental caries. All free smooth surfaces were evaluated to check whether or not there were white spots. Based on the subjects' caries experience, a calibrated clinician divided them into groups of high and low caries activity. The subjects were submitted to a salivary test (CARITEST SM) from the same batch number. Kappa statistics (kappa) were applied to verify the reproducibility of the simplified test, checked through interexaminer agreement when the results were classified by independent and blind means. The microbiological results were validated according to expressions of sensitivity and specificity. A moderate agreement was verified as the results were classified according to 6 scores (kappa=0.55), and the agreement was substantial when the results were classified according to high and low microbiological count (kappa=0.78). The sensitivity and specificity values were 0.59 and 0.85, respectively, showing that the test was more specific than sensitive, and could thus better identify the low caries risk subjects.