title: Fatigue load of teeth restored with bonded direct composite and indirect ceramic inlays in MOD class II cavity preparations.
abstract: OBJECTIVE
  This study compared the fatigue life of human maxillary premolars restored with direct composites and indirect ceramic inlays in mesio-occlusodistal (MOD) cavities.
  
  
  METHODS
  Ten human maxillary premolars were divided into two groups of five and restored with (1) direct composite restorations, or (2) pressed ceramic restorations. Standardized MOD cavities were prepared for both groups. Teeth in the direct composite group were restored with Z250 composite and Single Bond adhesive, and those in the ceramic group were restored with IPS Empress ceramic inlays. The ceramic inlays were luted with Single Bond and RelyX ARC cement. Under the applied test load of 11.17 kg, strain measurements were recorded from an electric resistance stain gauge bonded to the buccal surface. These strains were recorded for the (1) intact tooth, (2) cavity preparation, and (3) restored tooth. These strain measurements were used to calculate the relative tooth compliance values for each tooth. The fatigue loading was applied until reinforcement loss was registered by the strain gauge.
  
  
  RESULTS
  A one-way ANOVA showed no significant compliance difference between the intact and restored tooth conditions, and no significant difference in fatigue cycles to failure between the two groups.
  
  
  CONCLUSIONS
  There were both adhesive and cohesive failures in both restoration groups, indicating that the adhesive joint is not the only weak link in these restorations.
authors.affiliation: University of Washington, Seattle 98195, USA. alexshor38@hotmail.com
authors.forename: Alexander
authors.initials: A
authors.lastname: Shor
authors.forename: Jack I
authors.initials: JI
authors.lastname: Nicholls
authors.forename: Keith M
authors.initials: KM
authors.lastname: Phillips
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Libman
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003187:Compliance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification*; D003776:Dental Porcelain / Q000737:chemistry; D003793:Dental Restoration, Permanent; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007284:Inlays; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014070:Tooth / Q000503:physiopathology*
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; C075815:IPS-Empress ceramic; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; C115612:single bond; D003776:Dental Porcelain; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate