Estimation of dental plaque levels and gingival inflammation using a simple oral rinse technique

A simple, non-invasive test (the Oratest) has recently been proposed, which provides an estimate of oral microbial levels based on the rate of oxygen depletion in expectorated milk samples. Following 30 seconds of vigorous rinsing with sterilized milk, 3 ml of the expectorate is added to a test tube containing the redox indicator, methylene blue, and the time required for a color change from blue (i.e., aerobic conditions) to white (anaerobic conditions) at the bottom of the test tube is recorded. In the present study, Oratest scores were compared to clinical parameters (Plaque Index [PI] and Gingival Index [GI]) in a group of 49 volunteers. Significant correlations were found between the logarithm of Oratest results and PI (r = -0.58; P = 0.001) as well as GI (r = -0.66; P = 0.001). The data indicate that the Oratest provides a reliable estimate of gingival inflammation, thus extending the previously reported strong correlations between Oratest scores and microbial counts. The data suggest that the Oratest may have potential as a clinical and research tool.