title: [A light and scanning electron microscopic study of primary teeth in hypophosphatasia].
abstract: OBJECTIVE
  To investigate the features of primary tooth structure in hypophosphatasia.
  
  
  METHODS
  Three primary teeth from two patients at age of 3 yr-6 month and 4 yr-2 month, who were diagnosed hypophosphatasia. The structural changes of these teeth were examined by light microscopy, polarizing microscopy and scanning electron microscopy.
  
  
  RESULTS
  The complete absence of cementum was a prominent feature in all the teeth, three small island-shape cementun areas were found in scanning electron microscopy. A large number of resorptions were found on the root surfaces, particularly near apical portions of roots. The main findings included disturbances of dentin mineralization, hypoplasia or aplasia of root cementum and external resorption of root dentin.
  
  
  CONCLUSIONS
  The hypoplasia or aplasia of root cementum was thought to be the prime etiological factor in the early loss of primary teeth.
authors.affiliation: School of Stomatology, Beijing Medical University, Beijing 100081.
authors.forename: M
authors.initials: M
authors.lastname: Qin
authors.forename: G
authors.initials: G
authors.lastname: Shi
authors.forename: L
authors.initials: L
authors.lastname: Ge
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D007014:Hypophosphatasia; D008297:Male; D008855:Microscopy, Electron, Scanning; D014070:Tooth / Q000473:pathology* / Q000648:ultrastructure