title: Fracture strengths of three core restorative materials supported with or without a prefabricated split-shank post.
abstract: OBJECTIVE
  The aim of this study was to compare the fracture strengths of three restorative materials, a lanthanide reinforced composite (Ti-Core Natural), a silver amalgam (Tytin), and a hybrid glass ionomer (Advance), supported by either a multitiered, threaded split-shank post (Flexi-Flange) or with a dentin spur without a post.
  
  
  METHODS
  A total of 60 recently extracted single-rooted human teeth were divided into six groups of 10. All groups were stored at 100% humidity at room temperature for 1 week before testing. Each specimen was placed in a special jig at a 45-degree angle to the buccolingual axis and subjected to a load that was recorded in pounds and converted to Newtons on a universal testing machine, with a crosshead speed of 0.63 cm/minute until failure. Two-way analysis of variance followed by the Newman-Keuls pairwise multiple comparisons test were used to compare the results.
  
  
  RESULTS
  There was a statistically significant difference between core materials (p < 0.001), but not regarding post conditions. Ti-Core Natural material had a significantly larger mean failure threshold for fracture than either Tytin silver amalgam or Advance material and the letter two core materials (Tytin and Advance) do not differ from each other. There was no statistical difference between Ti-Core material supported by a post and Ti-Core material supported without a post.
authors.affiliation: Essential Dental Systems, S. Hackensack, N.J., USA.
authors.forename: B I
authors.initials: BI
authors.lastname: Cohen
authors.forename: M K
authors.initials: MK
authors.lastname: Pagnillo
authors.forename: A S
authors.initials: AS
authors.lastname: Deutsch
authors.forename: B L
authors.initials: BL
authors.lastname: Musikant
mesh_terms: D000704:Analysis of Variance; D002484:Cementation; D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008674:Metals, Rare Earth / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry; D011176:Post and Core Technique; D013314:Stress, Mechanical; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: C094366:Advance cement; C070606:Amalgambond; D003188:Composite Resins; D003722:Dental Alloys; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D008674:Metals, Rare Earth; D008689:Methacrylates; C079578:Ti-Core composite resin; C100742:All-Bond 2; C036886:tytin; D015036:Zinc Phosphate Cement; D003723:Dental Amalgam