| Budget Amount *help |
¥3,570,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥270,000)
Fiscal Year 2007: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
The aim of this study was to determine the variation in mineral ion (Ca, P, F) concentrations and the buffer capacity in dental plaque taken from different areas of the dentition that may be related to the caries status of tooth surfaces. We also clarified the distribution of S.mutans and S.sobrinus which are the most cariogenic bacteria. Plaque samples were collected from eight dentition sites, including the upper-anterior-buccal (UAB) and -lingual (UAL), upper-posterior-buccal (UPB) and -lingual (UPL), lower-anterior-buccal (LAB) and-lingual (LAL), and lower-posterior-buccal (LPB) and -lingual (LPL) regions. Significant differences among these 8 different sites were determined from Ca and P content, the Ca/P ratio, the buffer capacity (p<0.01) and from F content (p<0.05)as calculated by ANOVA. Plaque associated with the LAL region in relation to the orifices of the main salivary ducts and that is less prone to caries, had significantly higher levels of Ca, P, a higher Ca/P, buffer ca
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pacity and occurrence of S.mutans than any other dentition areas in adult subjects. Statistical analysis of the relationships among Ca, P, F and Ca/P showed that there were very strong associations between Ca and P, especially in the LAL and LPL regions where there is high exposure to saliva. Positive correlations were also found between Ca/P and F; however, partial correlation analysis showed that F did not correlate with P content if the Ca-factor was fixed. These results suggests that some F in dental plaque will be bound to mineral in a manner more dependent on the Ca rather than on the P.
On the other hand, the same result were obtained from infant subjects in P content (p<0.05) by ANOVA. However, with comparisons between the LAB and LAL, significant differences were seen in adult subjects but not in infant subjects. This may be due to the different salivary flow direction. Usually, children have developmental space in the lower anterior sites and salivary flow not only mesio-distal but also bucco-lingual.
We conclude that there was site-specificity of plaque mineral content, buffer capacity, and S.mutans occurrences, which may reflect the differences in exposure to saliva, resulting in differences in the local cariostatic challenge. Less
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