Site-specificity of mineral ions in 2-day dental plaque obtained from children and young adults

The aim of this study was to determine the variation in mineral ions (Ca and P) concentrations in 2-day dental plaque taken from different areas of the deciduous and the permanent dentition that may be related to the caries status of tooth surfaces obtained from children and young adults. We also compared those minerals between the deciduous and the permanent dentition. Plaque samples were collected from eight dentition sites, including the upper-anterior-buccal (UAB) and -lingual (UAL), lower-anterior-buccal (LAB) and -lingual (LAL), upper-posterior-buccal (UPB) and -lingual (UPL), lower-posterior-buccal (LPB) and -lingual (LPL) regions. Significant differences among these eight different sites were determined from Ca and P ions concentrations, as well as the Ca/P ratio, calculated by ANOVA. Plaque associated with the LAL region closest to the main salivary ducts and that is less prone to caries, had significantly higher levels of Ca, P ions concentrations, a higher Ca/P ratio than any other dentition areas in both children and young adult subjects. Statistical differences were seen in minerals between children and young adults. Ca ion concentrations in dental plaque from young adults were significantly higher than those of children at the LAL site. Statistical analysis of the relationships between Ca and P ions showed that there were strong associations between Ca and P ions, especially in the UPB, LAL and LPL regions where there is a high exposure to saliva. We conclude that there is a site-specificity of plaque mineral content in both children and young adults, which may reflect the differences in exposure to saliva, resulting in differences in the local cariostatic challenge.