Study of salivary strontium and silver concentrations in primary school children related to dental caries.

To investigate the relationship between the salivary Sr and Ag concentrations and tooth conditions, saliva was collected from 521 primary school children in Kitakyushu. The salivary Sr and Ag levels were determined using an atomic absorption spectrophotometry. The salivary Sr and Ag levels were 7.73 +/- 3.62 and 0.03 +/- 0.15 ng/ml, respectively, in the sound teeth group. No sex differences were noted in either element level, nor were there differences between the lower and upper grade groups. In the caries teeth group, the Sr and Ag levels were significantly higher than those in the sound teeth group. The Sr level was significantly increased by caries experience regardless caries being treated or untreated. In second to third grade children, in whom the fluoride experience rate was high, the Sr level tended to be lower than that in the other grades. The salivary Ag level increased as the number of teeth treated with silver alloy rose. These findings suggested that the salivary Sr level increases because of caries susceptibility, and F inhibits Sr dissolution from the teeth. The salivary Ag level varied depending on the type of dental filling and was dependent on the amount of silver alloy in children treated with low-fusing silver alloy.