title: Comparison of the fracture resistances of pulpless teeth restored with a cast post and core or carbon-fiber post with a composite core.
abstract: BACKGROUND
  The survival of pulpless teeth restored with a post and core system is a controversial issue.
  
  
  OBJECTIVE
  This study compared the fracture resistance of 2 types of restorations: teeth restored with prefabricated carbon-fiber posts and composite cores to cast dowel-core restored teeth.
  
  
  METHODS
  A total of 44 recently extracted sound premolars were randomly distributed into 2 equal groups: group I, restored with prefabricated carbon-fiber post and a composite core; and group II, with custom-cast type III gold alloy post and cores. The size and shape of the posts were identical in the 2 groups. All teeth were fully covered with a nonprecious cast crown. Fracture resistance was measured by applying a point force at 45 degrees to the long angle of the tooth.
  
  
  RESULTS
  Mean fracture threshold was 103.7 +/- 53.1 kg for group I versus 202.7 +/- 125.0 kg for group II (differences significant with P = .003). In group II, however, fracture nearly always affected the tooth itself, whereas in group I, the post-core nearly always failed first.
  
  
  CONCLUSIONS
  Significantly higher fracture thresholds were recorded for the cast post and core group. Teeth restored with cast posts typically showed fracture of the tooth, although at loads rarely occurring clinically.
authors.affiliation: School of Dentistry, Faculty of Medicine and Odontology, Santiago de Compostela University, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Martínez-Insua
authors.forename: L
authors.initials: L
authors.lastname: da Silva
authors.forename: B
authors.initials: B
authors.lastname: Rilo
authors.forename: U
authors.initials: U
authors.lastname: Santana
mesh_terms: D000293:Adolescent; D001641:Bicuspid; D002244:Carbon; D000077482:Carbon Fiber; D002858:Chromium Alloys; D003188:Composite Resins; D003442:Crowns; D003764:Dental Materials; D019232:Dental Restoration Failure; D006047:Gold Alloys; D006801:Humans; D066298:In Vitro Techniques; D011176:Post and Core Technique / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric; D019553:Tooth, Nonvital / Q000534:rehabilitation*
chemical_list: D000077482:Carbon Fiber; D002858:Chromium Alloys; D003188:Composite Resins; D003764:Dental Materials; D006047:Gold Alloys; D002244:Carbon