Apoptosis in the human periodontal membrane evaluated in primary and permanent teeth

Objective. Recent studies revealed a highly innervated layer in close proximity to the root surface in the periodontal membrane of human teeth. Persistence of the epithelial cells of Malassez along root surfaces without resorption has also been demonstrated. It is hypothesized that resorption is connected to apoptosis of the epithelial cells of Malassez. The purpose of this study is to localize cells undergoing apoptosis in the periodontal membrane of human primary and permanent teeth. Materials and methods. Human primary and permanent teeth were examined immunohistochemically for apoptosis and epithelial cells of Malassez in the periodontal membrane. All teeth examined were extracted in connection with treatment. Results. Apoptosis was seen in close proximity to the root surface and within the epithelial cells of Malassez. This pattern of apoptotis is similar in the periodontal membrane in primary and permanent teeth. Conclusions. The interrelationship between apoptotis and root resorption cannot be concluded from the present study. Apoptosis seen in close proximity to the root surface presumably corresponds to the highly innervated layer of the periodontal membrane. The function of this layer still needs to be elucidated.