title: 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.
  
  
  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.
authors.affiliation: Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Marie-Louise Bastholm
authors.initials: ML
authors.lastname: Bille
authors.forename: Bjarke
authors.initials: B
authors.lastname: Thomsen
authors.forename: Inger
authors.initials: I
authors.lastname: Kjaer
mesh_terms: D000293:Adolescent; D017209:Apoptosis / Q000502:physiology*; D001641:Bicuspid / Q000166:cytology; D053148:Caspase 3 / Q000032:analysis; D002648:Child; D004847:Epithelial Cells / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D016612:Paraffin Embedding; D010513:Periodontal Ligament / Q000166:cytology*; D014070:Tooth / Q000166:cytology*; D014079:Tooth Eruption, Ectopic / Q000473:pathology; D014092:Tooth Root / Q000166:cytology; D014094:Tooth, Deciduous / Q000166:cytology*; D055815:Young Adult
chemical_list: C505407:CASP3 protein, human; D053148:Caspase 3