title: In vitro evaluation of the retention of composite fiber and stainless steel posts.
abstract: OBJECTIVE
  This study compared the tensile retentive strength of composite fiber-reinforced dowels luted with a resin cement to stainless steel dowels luted with zinc phosphate cement.
  
  
  METHODS
  The crowns of 40 extracted human mandibular premolars were removed with a separating disc 1-mm coronal to the cementoenamel junction. The teeth were randomly divided into 4 groups (n = 10). A post space was prepared in each specimen to a depth of 9 mm, using the drill supplied by the respective manufacturer. For the stainless steel post group, 1.25-mm-diameter posts were cemented with zinc phosphate cement. For the composite fiber reinforced groups, posts with diameters of 1.00, 1.25, and 1.50 mm were luted with a Bisphenol A-Glycidyl Methacrylate (BIS-GMA) resin bonding system (Jeneric/Pentron, Wallingford, CT) according to manufacturer specifications. The specimens were stored in a sealed container with a moist environment for 24 hours, placed in a fixture in an 801 Materials Test Systems (MTS) machine (MTS Systems Corp, Minneapolis, MN), and loaded in tension at a rate of 5.0 mm/min until failure. Differences among the 4 groups were determined using a one-way analysis of variance and Tukey-B post-hoc tests (alpha = 0.05).
  
  
  RESULTS
  The mean loads to failure ranged from 43.9 +/- 10.4 kg for the stainless steel dowel group to 19.9 +/- 5.7 kg for the composite fiber-reinforced 1.00-mm-diameter group. The stainless steel post luted with zinc phosphate cement provided significantly greater tensile resistance than all composite fiber dowel groups. The retention of the 1.00-mm composite fiber-reinforced post was significantly less than the remaining groups.
  
  
  CONCLUSIONS
  Under the conditions of this study, the stainless steel dowel luted with zinc phosphate cement provided significantly greater retention.
authors.affiliation: LSUHSC School of Dentistry, New Orleans, LA 70119, USA. jgallo@lsuhsc.edu
authors.forename: John R
authors.initials: JR
authors.lastname: Gallo
authors.forename: Troy
authors.initials: T
authors.lastname: Miller
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Xu
authors.forename: John O
authors.initials: JO
authors.lastname: Burgess
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002484:Cementation; D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry*; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013718:Tensile Strength; D019231:Tooth Preparation, Prosthodontic / Q000295:instrumentation; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003722:Dental Alloys; C113550:FiberKor, sculpture; D019279:Resin Cements; C009753:fiberglass; D013193:Stainless Steel; D017438:Bisphenol A-Glycidyl Methacrylate; D015036:Zinc Phosphate Cement