Epithelial cell rest of Malassez have potential to produce enamel

Objectives: Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of Hertwig's epithelial root sheath. Little is known about the characteristics of ERM cells in particular whether these cells are enable to generate normal tissues. The object of this study is to determine if ERM can generate enamel tissue. Methods: We developed a novel culture method using 3T3 cells as a feeder layer which enabled ERM proliferation. ERM derived from porcine incisor tooth PDL were initially seeded in D-MEM containing 10% FBS. To obtain a pure population of cultured ERM cells, these cells were then incubated in medium without FBS. After selection, ERM were plated together with 3T3 cells. Subcultured ERM were combined with primary dental pulp cells collected from porcine third molars at the early stage of crown formation, and seeded onto collagen sponge scaffolds. Enamel-forming capacity was examined by implanting the seeded scaffolds into the omentum of immunodeficient rats. The constructs were maintained for 8 weeks in vivo and then examined by histology and immunohistochemistry.

Results: At 8 weeks after implantation, enamel-like tissues were observed which were positive for amelogenin, indicating the presence of well-developed ameloblasts in the implants. Conclusion: These results indicate subcultured ERM have the potential to produce enamel tissue.