bcl-2, p53, and MIB-1 in human adult dental pulp.

Little is known about the renewal of some groups of cells in dental pulp, and the occurrence and significance of physiological cell death in dental pulp is not yet understood. The possibility of odontoblast disappearance by apoptosis has been proposed, and the presence of apoptotic cells in the rat and human odontoblastic and subodontoblastic layers has been recently described. bcl-2 and p53 are proteins involved in the apoptotic pathway, whereas MIB-1 is a proliferating cell marker. The aim of our study was an immunohistochemical evaluation of bcl-2, p53, and MIB-1 in healthy normal pulps of young human subjects. With bcl-2 immunostaining, some positive cells were found in the odontoblastic and subodontoblastic layers, whereas with MIB-1, only a few stromal cells were positive, and all odontoblasts were consistently negative. No cells were positive to p53. The bcl-2 immunoreactivity of the cells of the odontoblastic and subodontoblastic layers could help to explain the presence of apoptotic cells found in these regions.