title: Effect of resin luting film thickness on fracture resistance of a ceramic cemented to dentin.
abstract: OBJECTIVE
  The aim of this study was to evaluate the fracture resistance of ceramic plates cemented to dentin as a function of the resin cement film thickness.
  
  
  METHODS
  Ceramic plates (1 and 2 mm thicknesses) were cemented to bovine dentin using resin composite cement. The film thicknesses used were approximately 100, 200, and 300 microm. Noncemented ceramic plates were used as control. Fracture loads (N) were obtained by compressing a steel indenter in the center of the ceramic plates. ANOVA and Tukey tests (alpha= 0.05) were used for each ceramic thickness to compare fracture loads among resin cement films used.
  
  
  RESULTS
  Mean fracture load (N) for 1-mm ceramic plates were: control-26 (7); 100 microm-743 (150); 200 microm-865 (105); 300 microm-982 (226). Test groups were significantly different from the control group; there was a statistical difference in fracture load between groups with 100 and 300 microm film thicknesses ( p < 0.01). Mean fracture load for 2-mm ceramic plates were: control-214 (111); 100 microm-1096 (341); 200 microm-1067 (226); 300 microm-1351 (269). Tested groups were also significantly different from the control group ( p < 0.01). No statistical difference was shown among different film thicknesses.
  
  
  CONCLUSIONS
  Unluted specimens presented significantly lower fracture resistance than luted specimens. Higher cement film thickness resulted in increased fracture resistance for the 1-mm ceramic plates. Film thickness did not influence the fracture resistance of 2-mm porcelain plates.
authors.affiliation: Department of Restorative Dentistry, Endodontics and Dental Materials, Bauru Dental School, University of São Paulo, Vila Altinópolis, Bauru, São Paulo 17012-170, Brazil. prakki@yahoo.com
authors.forename: Anuradha
authors.initials: A
authors.lastname: Prakki
authors.forename: Renato
authors.initials: R
authors.lastname: Cilli
authors.forename: Alcides U
authors.initials: AU
authors.lastname: Da Costa
authors.forename: Sergio E De Paiva
authors.initials: SE
authors.lastname: Gonçalves
authors.forename: Rafael F Lia
authors.initials: RF
authors.lastname: Mondelli
authors.forename: Jose C
authors.initials: JC
authors.lastname: Pereira
mesh_terms: D000818:Animals; D002417:Cattle; D002516:Ceramics / Q000737:chemistry*; D019245:Compressive Strength; D001840:Dental Bonding / Q000379:methods*; D019232:Dental Restoration Failure; D019279:Resin Cements / Q000737:chemistry*
chemical_list: D019279:Resin Cements