title: Fracture resistance of teeth restored with onlays of three contemporary tooth-colored resin-bonded restorative materials.
abstract: BACKGROUND
  There are uncertainties regarding the use of large indirect composites and ceramics in the restoration of posterior teeth.
  
  
  OBJECTIVE
  This study investigated the fracture resistance of teeth restored with restorations of 3 contemporary resin-bonded tooth-colored materials placed in a standardized onlay preparation.
  
  
  METHODS
  A random sample of preparations for tooth-colored onlays was obtained from a full service dental laboratory. A preparation was then duplicated in 30 natural teeth by copy milling. An additional 10 teeth were not prepared, and acted as a control. Ten onlays of each of the 3 materials (Belle Glass, SR Isosit, and Empress) were produced and resin bonded into place according to the manufacturers' instructions. The restorations were compressively loaded to fracture and the mode of failure recorded.
  
  
  RESULTS
  The fracture resistances obtained for the teeth restored with the composite material (mean 1.56 kN; SD 0.54) were greater than those obtained for the teeth restored with the ceramic material (mean 0.99 kN; SD 0.49) and the fiber-reinforced composite material (mean 0.99 kN; SD 0.56).
  
  
  CONCLUSIONS
  Teeth restored with composite onlay restorations demonstrated a higher fracture resistance than equivalent sized onlay restorations produced from fiber-reinforced composite or a ceramic material. Failure under compressive loading may be found to be less catastrophic when a fiber-reinforced composite rather than a composite or ceramic material is used.
authors.affiliation: Turner Dental School, The University of Manchester, Manchester, England. paul.brunton@man.ac.uk
authors.forename: P A
authors.initials: PA
authors.lastname: Brunton
authors.forename: P
authors.initials: P
authors.lastname: Cattell
authors.forename: F J
authors.initials: FJ
authors.lastname: Burke
authors.forename: N H
authors.initials: NH
authors.lastname: Wilson
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D000704:Analysis of Variance; D001641:Bicuspid / Q000503:physiopathology*; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D006801:Humans; D007284:Inlays; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014082:Tooth Fractures / Q000209:etiology / Q000503:physiopathology*
chemical_list: D000180:Acrylic Resins; D000538:Aluminum Silicates; C029012:Composite Dental Resin; D003188:Composite Resins; D003764:Dental Materials; C075815:IPS-Empress ceramic; D008689:Methacrylates; D011140:Polyurethanes; C110370:belleGlass; D003776:Dental Porcelain; C513704:Isosit