未萌出歯エナメル質表層のフッ素取り込みおよび保持に関する実験的研究

抄録

The purpose of the present study was to examine the posteruptive changes in surface enamel and to determine the effect of APF (acidulated phosphate fluoride) application on just erupted tooth enamel. Enamel blocks were obtained from unerupted third molars that were extracted for orthodontic reason. Some of these enamel blocks were mounted on an appliance in human oral cavity. After 1 to 32 days of exposure to the oral environment, the changes in fluoride concentration and enamel solubility were determined. The rest of enamel blocks were treated with APF solution for 3 minutes and were exposed in oral environment. After 3 hours to 32 days of exposure, fluoride concentration and enamel solubility were determined. When enamel blocks were treated with no fluoride, enamel solubility slowly decreased and was significantly at lower level after 32 days compared with controls. Fluoride concentration in enamel gradually increased and showed significantly higher level after 32 days. When enamel blocks were held in oral environment after APF application, fluoride concentration in enamel rapidly decreased with the passage of time and showed the lowest level after 2 days. But it was significantly higher than that of controls. And after 8 days it gradually increased. Enamel solubility reached a peak after 2 days and gradually decreased after that. From these results, it is concluded that posteruptive change is obviously shown only 32 days after eruption and that APF application on just erupted tooth enamel is effective for the posteruptive maturation.