title: [Relationship between vertical root fracture and the habits of chewing betel nut].
abstract: OBJECTIVE
  The aim of this article was to study the causes of vertical root fractures.
  
  
  METHODS
  Age and gender, personal history of the sickness and clinical features of vertical root fracture in 27 patients were studied.
  
  
  RESULTS
  Vertical root fracture tended to occur in patients with a higher mean age (54 years) and were more frequent in male (70%) than in female. Mesial or mesial-buccal roots of the first molars (78%) were the predilection site of vertical root fracture. All of the patients had chewed betel nut for 10 to 25 years. The occlusal surfaces were abrasive.
  
  
  CONCLUSIONS
  Vertical root fracture is associated with an excessive, repetitive, and heavy masticatory stress applied to a tooth.
authors.affiliation: Department of Stomatology, Second Xiangya Hospital, Central South University, Changsha 410011.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Gao
authors.forename: X M
authors.initials: XM
authors.lastname: Yin
authors.forename: H J
authors.initials: HJ
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D001114:Areca / Q000009:adverse effects*; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008409:Mastication; D008875:Middle Aged; D012189:Retrospective Studies; D014082:Tooth Fractures / Q000209:etiology*; D014092:Tooth Root / Q000293:injuries