Regional and Age-related Variations in Solubility and Fluoride Concentraion on the Surface of Human Tooth Enamel

Abstract

The purpose of this study was to examine the regional and age-related variations in the enamel solubility and the fluoride concentration on the surface of women's lower first premolars and to develop a technique to determine both enamel solubility and fluoride concentration using dissolved enamel from the same point on the tooth surface.The following results were obtained.1) Both the enamel solubility and the fluoride concentration could to be determined at the same window of enamel (3-mm diameter) on tooth surface.2) Fluoride concentration on the approximal surfaces were higher in older persons than in younger persons. The fluoride concentrations on the buccal surface increased transiently after eruption and then decreased. The decrease of fluoride concentration appeared to be most remarkable near the biting edge of the buccal surface in earlier stage.3) The differences in the fluoride concentrations between the approximal surfaces and the buccal surface in the group of unerupted teeth were not significant, but in the older group the approximal surface showed significantly higher fluoride concentrations than the buccal surface.4) The gourp of unerupted teeth showed significantly lower fluoride concentrations than the: group of erupted teeth, and the most scattered value of all.5) Enamel solubility tended to decrease first and then to drop to a plateau shortly after eruption.6) There were no differences in the enamel solubility between the approximal surfaces and the buccal susface, but in the older group the approximal surface. showed lower enamel solubility than the buccal surface.7) The group of unerupted teeth showed the least scattered values of all in the enamel solubility. The enamel solubility of the approximal surfaces tended to be more dispersed than that of the buccal surface.8) There was a reverse relationship between fluoride concentration and enamel solubility.