The effect of odontoblast conditioned media and dentin non-collagenous proteins on the differentiation and mineralization of cementoblasts in vitro

Objective: Cementum is an important mineralized tissue in root formation, however, the precise mechanism of cementum formation remains undetermined. The purpose of this study was to evaluate the effect of odontoblast conditioned media (CM) and dentin non-collagenous proteins (dNCPs) on the differentiation and mineralization of cementoblastic OCCM-30 cells. Methods: The CM of ameloblastic ALCs, odontoblastic MDPC-23 and OD-11, osteoblastic MG-63, and fibroblastic NIH3T3 cells were transferred to OCCM-30 cells. dNCPs were extracted directly from porcine and human dentin and applied to OCCM-30 cells. The results were evaluated through the analysis of the morphologic appearance, expression of cementum matrix genes, and the formation of mineralized nodules in vitro. Results: dNCPs hardly influenced proliferation, cell cycle modification, and chemotaxis of cementoblasts. Mineralization of cementoblasts was accelerated with dNCPs and CM from odontoblastic MDPC-23 and OD-11. RT-PCR analysis revealed the earlier and stronger expression of bone sialoprotein (BSP), alkaline phosphatase (ALP), and osteocalcin (OC) mRNAs in the MDPC23- and OD11-CM-treated OCCM-30 cells than those in the control OCCM-30 cells. The level of gene expression was also significantly higher in the dNCP-treated group than the control group. Conclusion: These results suggest that dentin matrix proteins, or the secreted products of odontoblasts, induced cementoblast differentiation and mineralization. These findings may contribute to the development of a periodontal treatment that includes cementum regeneration.