title: [Resistance to cyclic fatigue of pulpless teeth with flared root canals restored with three kinds of post-and-cores].
abstract: OBJECTIVE
  To observe the resistance to cyclic fatigue of maxillary incisors with flared canals restored with three post-and-core materials.
  
  
  METHODS
  Standard cylindrical samples with flared canals were made of 48 human maxillary central incisors and were assigned randomly to two groups (without ferrule and 2mm ferrule). Each main group was then divided into 3 sub-groups of 8 specimens and restored with cast metal post-core-crown,carbon fiber+resin composite post-core-crown ,and glass fiber+resin composite post-core-crown, respectively. Each group was subjected to a cyclic fatigue test, and the numbers of load cycles that had tooth fracture were measured with cyclic fatigue testing machine. All data were analyzed statistically for two-way ANOVA with SPSS 12.0 software package.
  
  
  RESULTS
  Fiber+resin composite post-core-crown showed significantly higher fatigue strength than cast metal post-core-crown in the two groups(P<0.05). Preparing dentin ferrules increased significantly fatigue resistance(P<0.05).
  
  
  CONCLUSIONS
  Fiber post-and-core system may get a long fatigue life in restoring pulpless teeth.Dentin ferrule preparation is necessary to enhance resistance to cyclic fatigue.
authors.affiliation: Department of Prosthodontics, China Medical University, Shenyang 110002, China. libinghong@yahoo.cn
authors.forename: Bing-hong
authors.initials: BH
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Zhao
authors.forename: Yang
authors.initials: Y
authors.lastname: Bao
authors.forename: Hong-jun
authors.initials: HJ
authors.lastname: Ai
mesh_terms: D003188:Composite Resins; D003442:Crowns; D003786:Dental Pulp Cavity; D003804:Dentin; D005898:Glass; D006801:Humans; D007180:Incisor; D011176:Post and Core Technique; D019228:Tooth Crown; D014082:Tooth Fractures; D019553:Tooth, Nonvital
chemical_list: D003188:Composite Resins; C009753:fiberglass