Abstract
The aim of this study was to clarify the distribution of mineral ion (Ca, P, F) concentrations, Ca/P and mode of binding F, i. e. the physiological significance of F in dental plaque from different areas of the dentition.4-day plaque samples were collected from 8 different sites of 15 male subjects living in Hokkaido (average age 25.2 yr. ); upper-anterior-buccal (UAB) and lingual (UAL), upperposteriorbuccal (UPB) and lingual (UPL), lower-anterior-buccal (LAB) and lingual (LAL), lowerposteriorbuccal (LPB) and lingual (LPL). Plaque samples were weighed, freeze-dried, and subjected to acid extraction, using a mixed-acid digestion procedure that was described by Margolis and Moreno (1992). The acid extracts were analyzed for Ca using atomic absorption, P using colorimetry and F using F ion electrode.
Statistical differences were seen in Ca, P, Ca/P (p<0.0001) and F (p<0.05) tested using two-way ANOVA. Plaque associated with the LAL, which is less prone to caries, had significantly highest levels of Ca, P and Ca/P based on Scheffe's test.
On the otherhand, the relationships among Ca, P, F and Ca/P were analyzed statistically. There were very strong associations between Ca and P, especially seen in LAL (r=0.988 p<0.0001) and LPL (r=0.997: p<0.0001), where are much prone to saliva. Positive correlations were found between Ca/P and F. Partial correlation analysis, however, showed that the F did not correlate with P if the Ca factor was fixed. These results suggested that some F in dental plaque could be bound to mineral, depending on Ca concentrations rather than P.
