The ameliorating role of epithelial cell rests of Malassez in the alleviation of experimentally-induced periodontitis in rats

Objective: The present study aimed to investigate the effect of experimentally-induced periodontitis on epithelial cell rests of Malassez (ERM) distribution and its subsequent role in regenerating periodontal ligament (PDL). Design: The study included 60 rats, aged seven months, randomly and equally divided into two groups: Group I, the control group, and Group II, the experimental group, in which ligature-periodontitis was induced. Ten rats from each group were euthanized at 1, 2, and 4 weeks. For ERM detection, specimens were processed for histological and immunohistochemical examination of cytokeratin-14. Additionally, specimens were prepared for the transmission electron microscope. Results: Group I demonstrated well-organized PDL fibers with few ERM clumps close to the cervical root portion. In contrast, one week after periodontitis induction, Group II showed marked degeneration, a damaged cluster of ERM cells, narrowing of the PDL space, and early signs of PDL hyalinization. After two weeks, a disorganized PDL was observed with the detection of small ERM clumps enclosing very few cells. After four weeks, PDL fibers were reorganized, and ERM clusters increased significantly. Notably, ERM cells were positive for CK14 in all groups. Conclusion: Early-stage ERM may be affected by periodontitis. However, ERM is capable of recovering its putative role in PDL maintenance.