1,25(OH)₂D₃ appears to indirectly induce osteoclast formation by up-regulating RANKL expression in marrow stromal cells.A recent study has shown that BMP-2 enhances the induction of osteoclast formation by 1,25(OH)₂D₃,but little is known about the mechanism of the promoting effect of 1,25(OH)2D3 and BMP-2 co-stimulation on osteoblast-osteoclast interaction. In this study,we investigated the time-dependent expression of RANKL and VDR in osteoblasts co-stimulated with 1,25(OH)₂D₃ and BMP-2.The mRNA expression of RANKL in Osteoblast-Like MC3T3-E1 Cells increased significantly after co-stimulation with 1,25(OH)₂D₃ and BMP-2 compared with that stimulated with 1,25(OH)₂D₃ only.VDR expression also increased significantly after co-stimulation.These results suggested that BMP-2 may accelerate the 1,25(OH)₂D₃ –induced osteoclast formation by through enhance the expression of VDR and following RANKL in osteoblast.

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The purpose of the present study is to examine the influence of melatonin on the structure and composition of tooth dentin through the analytical and histological studies. In this experiment, five, six, and seven-day old SD rats were used. The number and size of calcospherites in predentin increased in proportion to the concentration of melatonin administered. In the high concentration group, the strong expression of ALP was observed. In EPMA analysis, Ca and P content were increasing by the melatonin treated group. By laser Raman microprobe spectrometry, a peak of PO₄^3- is highly at a high concentration group. It is considered that melatonin participates in the formation of incremental lines and the calcification mechanism of dentin.

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The Act on the Safety of Regenerative Medicine was passed approved by Japanese Diet in November 2013, and started in 25^th November 2014. This Act covers cell therapies those safety and efficacy have not been established and purpose of therapy is classified as one of the followings: (1) technologies intended for reconstruction, repair, or formation of structure or functions of the human body or (2) those intended for treatment or prevention of human diseases by use of processed cells. This act will be applied not only to clinical trials but also cell therapies administered in daily practice outside of national health insurance.Dental regenerative medicine such as platelet-rich plasma for wound healing is also covered by this act. In this review, overview of the Act on the Safety of Regenerative Medicine, and the relationship with dental regenerative medicine are introduced.

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