Histopathological and immunohistochemical study of the characteristics of dental follicle

Abstract

The purpose of this study was to examine the histopathological and immunohistochemical characteristics of the dental follicle (DF) attached to impacted tooth. A total of 38 cases of DF diagnosed histopathologically between 2000 and 2011 at the Department of Oral Pathology, Nihon University School of Dentistry, Matsudo City, Japan were used in the study. Among the 38 cases, 10 cases which did not undergo decalcification were selected for immunohistochemistry. Histologically, the DF was composed of inner and outer layers. In the inner layer, myxoid tissue, dilated capillaries and peripheral nerve were observed in 100%, 83.3% and 26.3% of the cases respectively. Vessel density in the inner layer is 11 times more than in the outer layer. Capillary dilatation in the inner layer was observed in 83.3% with 107.8 ±124.0μm2 but was not observed in the outer layer with 3.4±2.4 μm2 in average, either. Lymph vessel density in the inner layer is more frequent than in the outer layer. Odontogenic epithelial islands and calcification were more prominent in the inner layer (55.3%, 31.6%) compared to those in the outer layer (2.9%, 2.6%). The mesenchymal cells in the inner layer were positive to Vimentin and α-SMA but only weakly positive to FGF-2 and VEGF. Cells positive to CD68 were scattered and cells focally positive to Runx2 were observed near the region of inflammatory cell infiltration. The odontogenic epithelial islands were positive to FGF-2 and p63. The results suggest that the ectomesenchymal cells in the inner layer of the DF are concerned with abundant vascular formation. Further, inflammatory irritation to the inner layer might have caused osteoblastic differentiation. © 2012 The Hard Tissue Biology Network Association Printed in Japan, All rights reserved.