title: Influence of post-thickness and material on the fracture strength of teeth with reduced coronal structure.
abstract: OBJECTIVE
  To evaluate the fracture strength of endodontically treated teeth with reduced coronal structure reinforced with glass-fiber posts and cast posts and core (nickel-chromium alloy) with different thickness.
  
  
  METHODS
  Forty maxillary central incisors were sectioned at 1 mm of the cementoenamel junction and endodontically treated. The teeth were divided into four groups (n = 10) and restored with cast post and core and glass-fiber posts with diameters of 1.5 mm and 1.1 mm. The fracture strength was evaluated using a Universal Testing Machine (Instron 1144) at 45° of angulation. The results were submitted to analysis of variance two-way and Tukey's test (P < 0.05). The failure mode was also evaluated.
  
  
  RESULTS
  Cast post and core were statistically superior to the glass-fiber posts with the self-post diameter (P = 0.001). When the self-post material was considered, no significant difference was observed between the two post-diameters (P = 0.749). The glass-fiber post-groups presented more fractures in the cervical third than the cast post and core groups.
  
  
  CONCLUSIONS
  Teeth restored with cast post and cores present higher fracture strength than those reinforced with glass-fiber posts. An increased post-thickness does not increase the fracture strength. Glass-fiber posts lead to less severe fractures.
authors.affiliation: Department of Prosthodontics and Periodontics, School of Dentistry, Campinas State University - FOP/UNICAMP, Av. Limeira, 901 Piracicaba, SP, Brazil.
authors.forename: Ataís
authors.initials: A
authors.lastname: Bacchi
authors.forename: Mateus Bertolini Fernandes
authors.initials: MB
authors.lastname: Dos Santos
authors.forename: Marcele Jardim
authors.initials: MJ
authors.lastname: Pimentel
authors.forename: Conrado Reinoldes
authors.initials: CR
authors.lastname: Caetano
authors.forename: Mário Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Rafael Leonardo Xediek
authors.initials: RL
authors.lastname: Consani
keywords: Fracture strength; intracanal posts; root canal