title: Adhesive bond strength between a ceramic system and composite resin bonded by resinous cement submitted or not to thermocycling process.
abstract: OBJECTIVE
  The success of ceramic restorations is influenced by biocompatibility and resistance provided after bonding with an adhesive system. The aim of this in vitro study was to evaluate the adhesive bond strength between ceramic (IPS Classic V, Ivoclar Vivadent) and composite resin (Z-250, 3M), submitted or not to thermocycling treatment.
  
  
  METHODS
  Forty ceramic cylinders were obtained with the following dimensions: 2 mm diameter and 3 mm high. The bond surface was polished with polishing paper (#600), conditioned with 10% hydrofluoric acid and silanized, according to manufacturer's recommendations. Later, the ceramic cylinders were bonded, with resinous cement (Rely X, 3M) to composite resin cylinders (Z-250, 3M) with the same dimensions, under 1 kg load. The assemblies were divided into two groups submitted to the following treatments: Group 1 (control): immersed in distilled water at 37 degrees C for 3 days, and Group 2: thermocycled (500 cycles) into two baths (5 degrees C and 55 degrees C), with 1 min of storing time each. In order to evaluate the adhesive resistance, the assemblies were tractioned in a universal testing machine (EMIC MEM 2000) with a crosshead speed of 0.5 mm/min. Obtained data were submitted to statistical analysis (ANOVA and Tukey's test).
  
  
  RESULTS
  The means (MPa) and standard deviation obtained for Groups 1 and 2 were, respectively, 29.64+/-9.48 and 17.55+/-4.78. Group 1 presented significantly higher values than Group 2 (P<0.05).
  
  
  CONCLUSIONS
  The results obtained in this study showed that the thermocycling procedure decreased the adhesive resistance between the materials studied.
authors.affiliation: Department of Dental Materials and Prostheses, Faculty of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Do Nascimento
authors.forename: R
authors.initials: R
authors.lastname: Tiossi
authors.forename: S C
authors.initials: SC
authors.lastname: Hallak Regalo
authors.forename: S
authors.initials: S
authors.lastname: Siéssere
authors.forename: M
authors.initials: M
authors.lastname: Da Glória Chiarello De Mattos
authors.forename: J P
authors.initials: JP
authors.lastname: Mardegan Issa
mesh_terms: D002516:Ceramics; D003188:Composite Resins; D008422:Materials Testing; D019563:Mechanics; D019279:Resin Cements; D013696:Temperature
chemical_list: D003188:Composite Resins; D019279:Resin Cements