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

Abstract

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 inter-relationship 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.

Key Words::

• root resorption
• epithelial cells of Malassez
• apoptosis
• periodontal regeneration

Acknowledgements

Dentists in municipal clinics in Zealand and dentists at the Department of Orthodontics, School of Dentistry, University of Copenhagen, Denmark forwarded primary and permanent teeth for histological and immunohistochemical analyse. Thanks to Maria Kvetny, MA, for linguistic support and consultancy in manuscript preparation. Funding was provided by: Tandlaegeforeningen (KOF/Calcinfonden and FORSKU), Copenhagen, Denmark; The Danish Medical Research Council (under Danish Agency for Science, Technology and Innovation), Copenhagen, Denmark; and the Faculty of Health Sciences, University of Copenhagen, Denmark.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.