title: [Effects of change of crown contour on health of gingiva].
abstract: OBJECTIVE
  To study the effects of different excessive crown contours on the health of periodontium.
  
  
  METHODS
  A total of 63 posterior teeth of 12 volunteers were randomly divided into three groups and each group was consisted of 21 teeth. The buccal surfaces of the teeth were overcontoured 0.2 mm, 0.5 mm, and 0.8 mm respectively. At the point of 1 week, 4 weeks and 8 weeks, gingival cervical fluid (GCF) were collected, GCF-aspartate aminotransferase (GCF-AST) and GCF-alkaline phosphatase (GCF-ALP) levels were tested and the debris amount was assessed for three groups.
  
  
  RESULTS
  The 0.8 mm group presented most amount of GCF, highest level of GCF-AST, GCF-ALP and most debris. The 0.5 mm group was the second. When the excess was 0.2 mm, all indexes showed no statistically significant change.
  
  
  CONCLUSIONS
  Excessive crown contour is unfavourable to periodontium health. The more the teeth are excessively contoured, the more they impair periodontium.
authors.affiliation: Special Dental Department, Peking University School of Stomatology, Beijing 100081, China.
authors.forename: X
authors.initials: X
authors.lastname: Deng
authors.forename: X
authors.initials: X
authors.lastname: Hu
authors.forename: X
authors.initials: X
authors.lastname: Ouyang
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000378:metabolism; D001219:Aspartate Aminotransferases / Q000378:metabolism; D005260:Female; D005883:Gingival Crevicular Fluid; D006801:Humans; D008297:Male; D010519:Periodontium / Q000502:physiology*; D019228:Tooth Crown / Q000473:pathology*
chemical_list: D001219:Aspartate Aminotransferases; D000469:Alkaline Phosphatase