title: Effect of antioxidant treatment on bond strength of a luting resin to bleached enamel.
abstract: OBJECTIVE
  The aim of this study was to comparatively investigate the effect of antioxidant treatment and delayed bonding after bleaching with carbamide peroxide on the shear bond strength (SBS) of a luting resin to enamel.
  
  
  METHODS
  Forty flat enamel surfaces were prepared from freshly extracted human molars using a low speed diamond saw, then divided into three bleaching groups (n=10/group) and a control group (n=10). Group 1 consisted of specimens bonded immediately after bleaching. Group 2 specimens were treated with an antioxidant agent, 10% sodium ascorbate, while Group 3 specimens were immersed in artificial saliva for 1 week after bleaching. Specimens in Group 4 were not bleached, but immersed in artificial saliva for 1 week before bonding. Forty ceramic blocks (Empress 2, Ivoclar) were prepared and luted to teeth using a dual-curing resin cement (Variolink II, Ivoclar). The specimens were thermocycled and the SBS tests were performed using a universal testing machine (crosshead speed: 0.5mm/min). Fracture analysis of the bonded surfaces was done using a scanning electron microscope. Statistical analysis was carried out by Kruskall-Wallis and Mann-Whitney U-tests.
  
  
  RESULTS
  While the samples that were immediately bonded after bleaching (Group I) demonstrated significantly lower shear bond strengths and 10% sodium ascorbate group (Group II) demonstrated significantly higher bond strengths than control group samples (p<0.05), no significant differences were found among delayed bonded group and control group (p>0.05).
  
  
  CONCLUSIONS
  Using sodium ascorbate with a concentration of 10% may be reliable for reversing the compromised bond strength.
authors.affiliation: Ege University, School of Dentistry, Department of Prosthodontics, Izmir, Turkey. bulentgokce@yahoo.com
authors.forename: Bülent
authors.initials: B
authors.lastname: Gökçe
authors.forename: M Erhan
authors.initials: ME
authors.lastname: Cömlekoğlu
authors.forename: Birgül
authors.initials: B
authors.lastname: Ozpinar
authors.forename: Murat
authors.initials: M
authors.lastname: Türkün
authors.forename: Ayşegül Demirbaş
authors.initials: AD
authors.lastname: Kaya
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D000077463:Carbamide Peroxide; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D003799:Dental Stress Analysis; D004338:Drug Combinations; D006801:Humans; D008964:Molar, Third; D010545:Peroxides / Q000494:pharmacology; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D012464:Saliva, Artificial; D033081:Shear Strength; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D003738:Dental Cements; D004338:Drug Combinations; D010545:Peroxides; D019279:Resin Cements; D012464:Saliva, Artificial; D000077463:Carbamide Peroxide; D014508:Urea; D001205:Ascorbic Acid