title: Evaluation of fiber post-supported restorations under simulated occlusal loading.
abstract: BACKGROUND
  There is a lack of information comparing the effect of a rigid versus flexible post on the marginal seal of post-and-core supported crowns subjected to long-term repeated loading.
  
  
  OBJECTIVE
  The purpose of this study was to examine the leakage pattern of complete coverage restorations retained with either a metal or fiber-reinforced resin post under simulated occlusal loads.
  
  
  METHODS
  Thirty-six maxillary central incisors were endodontically treated and provided with a post-and-core supported crown. One group was restored with a fiber-post (EasyPost Lux) and another was restored with a metal post (Parapost) (n=12). Both groups were loaded for 120,000 cycles to 70 N while immersed in a dye solution. A control group (n=12), similarly restored with a fiber post but not loaded, was also included. All teeth were transversely sectioned serially from the tooth-core interface towards the apex. Digital photographs were made to determine the extent of leakage on the buccal, mesial, palatal, and distal aspects along the depth of the post. A nonparametric Kruskal-Wallis test was used to determine any difference between groups (α=.05).
  
  
  RESULTS
  Dye penetration occurred in all stress-cycled specimens and was more extensive on the palatal than other aspects. The fiber-post group cyclically stressed to 70 N showed a significantly greater amount of leakage than the control or the Parapost group (P<.05).
  
  
  CONCLUSIONS
  In in vitro testing, the rigidity of the post influenced the seal of post-and-core-supported crowns at the palatal margin.
authors.affiliation: Comprehensive Dental Care (Endodontics), Faculty of Dentistry, The University of Hong Kong, Hong Kong.
authors.forename: J W W
authors.initials: JW
authors.lastname: Chang
authors.forename: Irwan
authors.initials: I
authors.lastname: Soo
authors.forename: Gary S P
authors.initials: GS
authors.lastname: Cheung
mesh_terms: D001732:Bite Force; D003763:Dental Leakage; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D005898:Glass; D006801:Humans; D007180:Incisor / Q000502:physiology; D011176:Post and Core Technique; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D019553:Tooth, Nonvital
chemical_list: C009753:fiberglass; D013193:Stainless Steel