The purpose of the present study was to clarify the changes in fluoride concentrations of the surface enamel of young permanent incisors just after eruption.
Fluoride concentrations and the acid dissolution rate of the surface enamel in the six normal lower central incisors in situ were measured by atlenamel micro-sampling technique.
Samples obtained were from four males and two females with an average age of 6.6 yr.
The fluoride concentration of the surface enamel in situ were compared with those of the extracted teeth.
The results were as follows:
1) Mean Ca/P (w/w) values was 1.96.
2) The acid dissolution rate had a tendency to decrease from the enamel surface towerd the deep layer. There was a reversed relationship between the fluoride concentration and acid solbility.
3) The fluoride concentration was decreased proportionally from the enamel surface toward the inner part.
4) The fluoride concentrations in teeth just after eruption was a significantly lower than those of the extracted teeth at the layer deeper than 3μm. (P<0.05)