Abstract
The aim of this study was to investigate differences in chemical reactions during de- and remineralization of eroded enamel of deciduous and permanent teeth, as well as the effects of 950 ppmF sodium fluoride application. We extracted 20 deciduous molars and 20 permanent premolars from human subjects, and examined the rate of changes in tooth mineral content using a pH cycling method. The time period for each cycle was set at 22 hours. Enamel blocks were immersed in re-mineralizing solution for 2 hours at pH 7.0, then in de-mineralizing solution for 5 minutes at pH 3.0, followed by re-mineralizing solution for 6 hours 30 minutes at pH 7.0. This process was repeated 3 times for the non-fluoride-treated group. For the fluoride-treated group, immersion in a sodium fluoride solution (950 ppmF) for 3 minutes was added before the second re-mineralization step. To evaluate de- and remineralization, the rate of change (vol %) in mineral content calculated from the P concentration in each solution was used. Following are our results.1.A comparison of the rate of change in mineral content between deciduous and permanent teeth showed no significant difference in the non-fluoride-treated group. In contrast, a greater level of chemical reaction was seen in deciduous teeth during re-mineralization in the fluoride-treated group.2.The total rates of change in mineral content for both deciduous and permanent teeth showed a significant difference between the non-fluoride- and fluoride-treated groups. However, no significant differences between deciduous and permanent teeth were seen within each group.Although we used a pH 3.0 de-mineralizing solution with the supposition that tooth erosion would result, our findings revealed that application of a 950 ppmF fluoride solution before re-mineralization had no significant inhibition of de-mineralization related to tooth erosion in both deciduous and permanent teeth, suggesting that it is possible to stimulate re-mineralization, and maintain the balance of de- and re-mineralization.
