title: Diametral and compressive strength of dental core materials.
abstract: BACKGROUND
  Strength greatly influences the selection of core materials. Many disparate material types are now recommended for use as cores. Cores must withstand forces due to mastication and parafunction for many years.
  
  
  OBJECTIVE
  This study compared the compressive and diametral tensile strengths of 8 core materials of various material classes and formulations (light-cured hybrid composite, autocured titanium containing composite, amalgam, glass ionomer, glass ionomer cermet, resin-modified glass ionomer, and polyurethane).
  
  
  METHODS
  Materials were manipulated according to manufacturers' instructions for use as cores. Mean compressive and diametral strengths with associated standard errors were calculated for each material (n = 10). Analyses of variance were computed (P <.0001) and multiple comparisons tests discerned many differences among materials.
  
  
  RESULTS
  Compressive strengths varied widely from 61.1 MPa for a polyurethane to 250 MPa for a resin composite. Diametral tensile strengths ranged widely from 18.3 MPa for a glass ionomer cermet to 55.1 MPa for a resin composite. Some resin composites had compressive and tensile strengths equal to those of amalgam.
  
  
  CONCLUSIONS
  Light-cured hybrid resin composites were stronger than autocured titanium containing composites. The strengths of glass ionomer-based materials and of a polyurethane material were considerably lower than for resin composites or amalgam.
authors.affiliation: University of Southern California School of Dentistry, Los Angeles, CA 90033, USA.
authors.forename: G C
authors.initials: GC
authors.lastname: Cho
authors.forename: L M
authors.initials: LM
authors.lastname: Kaneko
authors.forename: T E
authors.initials: TE
authors.lastname: Donovan
authors.forename: S N
authors.initials: SN
authors.lastname: White
mesh_terms: D000704:Analysis of Variance; D016722:Cermet Cements; D003188:Composite Resins / Q000737:chemistry; D019245:Compressive Strength; D003722:Dental Alloys; D003723:Dental Amalgam / Q000737:chemistry; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D008298:Maleates; D008422:Materials Testing; D011140:Polyurethanes; D011176:Post and Core Technique; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D014025:Titanium
chemical_list: D016722:Cermet Cements; D003188:Composite Resins; C074317:Core Paste composite resin; D003722:Dental Alloys; D005899:Glass Ionomer Cements; D008298:Maleates; D011140:Polyurethanes; C099128:Prodigy; C084550:Vitremer; C078906:Herculite Condensable; C079578:Ti-Core composite resin; D003723:Dental Amalgam; C040964:Ketac-Fil; C072894:Valiant PhD; D014025:Titanium