The Connection between the Periodicity Incremental Lines of Tooth Dentin and the Secretion Rhythm of Melatonin of the Signaling Molecules of Biological Clock

Abstract

The purpose of the present study is to examine the relationship between the periodicity of incremental lines in dentin of teeth and the role of melatonin. In this experiment, 5- and 6-day, 7- and 8-days after birth SD rats were used. In the low melatonin concentration group, the light staining layer became narrow. In the high melatonin concentration group, this layer disappeared. The number and size of calcospherites in predentin increased in proportion to the concentration of melatonin administered. The new incremental line was confirmed in both the incisor and molar dentin of the melatonin treated groups. In SEM-EDS analysis, Ca and P content were increasing by the melatonin treated group compared with the control group. It is considered that melatonin participates in the formation of incremental lines and the calcification mechanism of the odontoblast. The work was supported by KAKENHI (23592727).