Relation of motility of subgingival microflora as a clinical parameter to periodontal disease status in human subjects.

Background/aims: The purpose of this study was to evaluate the possible relationship between the motility of subgingival microflora and 5 clinical parameters commonly used in dental clinics.

Method: The clinical parameters were pocket depth, gingival inflammation, plaque accumulation, bleeding on probing and pus discharge. The motility of human subgingival microflora was estimated as the number of pixels remaining after subtraction of serial video frames using a high speed shutter camera and image analysis system, and was defined as the sum of pixels of 10 successive subtractions per sample over a 10-s time period.

Results: The bacterial motility showed significant positive, moderate or low associations with the five clinical parameters. The highest correlation was observed between the bacterial motility and pocket depth (r=0.36, p=0.0001). Furthermore, clinically defined periodontal healthy and diseased sites were significantly different with respect to the bacterial motility (p<0.0001). To determine whether the bacterial motility was dependent or independent of the other clinical variables, the data were analyzed based on common factor analysis. Three factors were extracted and explained about 75% of the variance of the original 6 clinical parameters. Only the bacterial motility had a positive coefficient for all these three factors. The plot of bacterial motility was placed separately from those of other variables in the scatterplot of the loadings of factor 2 versus factor 1 and factor 2 versus factor 3.

Conclusions: This suggests that bacterial motility may be an independent variable among the clinical parameters. Taken together, these data indicate that bacterial motility provides unique information about the clinical periodontal condition and may be a useful tool for the monitoring of subgingival plaque in relation to periodontal disease.