title: Computer-aided-design/computer-assisted-manufactured adhesive restoration of molars with a compromised cusp: effect of fiber-reinforced immediate dentin sealing and cusp overlap on fatigue strength.
abstract: BACKGROUND
  Cracked teeth may traditionally require the use of complete coverage crowns. Alternative conservative treatments involve the use of adhesive inlays/onlays with the possibility of including a fiber patch to reinforce the cracked cusp.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the fatigue strength of compromised molars restored with computer-aided-design/computer-assisted-manufactured (CAD/CAM) composite resin inlays/onlays with and without fiber-reinforced immediate dentin sealing (IDS).
  
  
  METHODS
  Large mesio-occluso-distal preparations with cracked/undermined palatal cusps were simulated on 40 extracted maxillary molars. All teeth received IDS (Optibond FL, Kerr, Orange, CA, USA), and composite resin (Paradigm MZ100, 3M-ESPE, St. Paul, MN, USA) inlays (N = 20) and onlays (N = 20). A fiber patch (Ribbond, Ribbond Inc., Seattle, WA, USA) was applied in half of the preparations. Restorations were adhesively luted with pre-heated composite resin (Z100, 3-M ESPE) and submitted to cyclic isometric loading at 5 Hz, starting with a load of 50 N (5,000 cycles), followed by stages of 150, 300, 450, 600, 750, 900, and 1,050 N at a maximum of 25,000 cycles each. Specimens were loaded until fracture or to a maximum of 180,000 cycles. Groups were compared using the life table survival analysis.
  
  
  RESULTS
  Differences in survival probability were found (p = 0.04). The inlay group with fiber patch failed at an average load of 870 N, and none of the specimens withstood all 180,000 load cycles; survival rates of inlays and onlays without fibers, and onlays with fibers were 10, 30, and 50%, respectively.
  
  
  CONCLUSIONS
  Onlays (with or without fibers) increased the fatigue resistance of compromised molars in this in vitro study.
authors.affiliation: Division of Restorative Sciences, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, CA magne@usc.edu, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Magne
authors.forename: Luís L
authors.initials: LL
authors.lastname: Boff
authors.forename: Elisa
authors.initials: E
authors.lastname: Oderich
authors.forename: Antônio C
authors.initials: AC
authors.lastname: Cardoso
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D017076:Computer-Aided Design; D003387:Cracked Tooth Syndrome / Q000628:therapy*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D007284:Inlays; D008963:Molar / Q000293:injuries; D011095:Polyethylenes; D019279:Resin Cements / Q000627:therapeutic use*; D016019:Survival Analysis; D019228:Tooth Crown / Q000293:injuries*
chemical_list: D003188:Composite Resins; D011095:Polyethylenes; C084063:RIBBOND; D019279:Resin Cements