Kamal, Abeer; Allam, Eman; Dehis, Mohammed; Zunt, Susan; Windsor, L. Jack
Residual dental follicles surrounding the crowns of impacted teeth may represent a significant risk for their potential pathological changes. In this study, the expression levels of cell cycle proteins, proliferating cell nuclear antigen (PCNA), cyclin D1, and p21 were evaluated using immunohistochemistry. Twenty-two impacted mandibular third molars in 17 healthy individuals were evaluated in this study. They were divided into two groups on the basis of the depth of impaction: the partially impacted group and the fully impacted group. The impacted teeth were surgically removed and the surrounding follicle was curetted and examined by immunohistochemistry to evaluate whether there was a difference in cell cycle regulation between the two groups. PCNA was expressed in most of the epithelial cells with no significant difference between the groups. The p21 expression was significantly higher in the full bony impaction group. Cyclin D1 expression was expressed at low levels with no significant difference between the groups. Weak cyclin D1 expression was consistent with high p21, a negative regulator of the cell cycle. The high p21 expression could be a compensatory mechanism to the high PCNA levels. These results suggest the possibility that dental follicles associated with full bony impactions possess different cellular activities compared with partial bony/soft-tissue impactions.