Abstract
The process of enamel maturation during the period from enamel formation to tooth eruption was studied in the thin sections prepared from bovine incisors. The degree of mineralization and the concentrations of Ca, P and some trace elements (Mg and Cl) were measured at 4 sites on the sections from incisal to cervical.
The results were as follows:
1. At the stage of 1/2 crown formation, concentrations of Ca and P in the enamel were 50% of the level of an erupted tooth. When crown formation was completed, the Ca and P concentrations had reached levels higher than 80% of the erupted tooth enamel. Analyses using microradiography indicated that the degree of enamel calcification was below 1% of the too t h at the time of eruption. Mg and Cl concentrations showed a slow incr e ase.
2. In the early stage of root formation, the concentrations of Ca and P were equal to those in the erupted tooth enamel. However the level of calci f i cation was still low and kept rising. The concentrations of Mg and C l were going up at the same rate as in the former stage.
3. In the late stage of root formation, there was no change in the concentrations of Ca and P. However a remarkable increase in the level o f calcification was observed, and was higher in the inner enamel than on the enamel surface. The greatest increase of Mg concentration was found on t h e enamel surface up to a depth of 60, um, whereas, the inner layer of the enam e l had a lower level of concentration. The continuing increase of Cl co n centration was also found in this stage.
4. During the stage of tooth eruption, there was no change in the concentrations of Ca, P and Mg, but the degree of enamel calcification was rising. It was found that the level of calcification in the erupted part of the enamel was higher than that of the unerupted part. The concentration of Cl had increased at the inner layer, and reached almost the same level in whole area.
