title: In situ effect of 10% carbamide peroxide on resin-dentin bond strengths: a novel pilot study.
abstract: OBJECTIVE
  This pilot study used a novel study design to evaluate the effect of a 10% carbamide peroxide bleaching gel on the bond strength of a resin-based composite system to dentin.
  
  
  METHODS
  Dentin disks were obtained from human third molars, polished to 600 grit, and mounted on the palatal aspect of a removable orthodontic retainer. Two disks were exposed to a 10% carbamide peroxide bleaching gel for 2 h/d for 21 days, whereas two disks were not treated and served as controls. A retainer was worn by the participant regardless of whether bleaching was used, simulating the action of the saliva/oral fluids on the dentin specimens. After the treatment phase, the dentin disks were retrieved and a resin-based composite system was applied to the specimens following manufacturer's instructions. Composite dentin "sticks" were obtained and tested in microtensile mode. Bond strength values were obtained for treated (n = 20) versus nontreated (n = 26) dentin and were analyzed statistically.
  
  
  RESULTS
  Mean bond strengths values (SD) were 29.9 MPa (6.2) and 39.2 MPa (5.8) for treated and nontreated dentin specimens, respectively (p < .001).
  
  
  CONCLUSIONS
  The results of this study suggest that nightguard (home) bleaching with 10% carbamide peroxide for 2 h/d for 21 days significantly affects resin-dentin bond strengths when dentin is exposed to bleaching material. CLINICAL SIGNIFICANCE The findings of this novel pilot study imply that dentin bonding, such as to exposed root surfaces and cervical areas of the teeth, should not be performed immediately after bleaching with 10% carbamide peroxide.
authors.affiliation: Department of Operative Dentistry, University of Joinville (Univille), SC, Brazil.
authors.forename: Luiz C
authors.initials: LC
authors.lastname: Miguel
authors.forename: Luiz N
authors.initials: LN
authors.lastname: Baratieri
authors.forename: Sylvio
authors.initials: S
authors.lastname: Monteiro
authors.forename: André V
authors.initials: AV
authors.lastname: Ritter
mesh_terms: D000328:Adult; D017438:Bisphenol A-Glycidyl Methacrylate; D000077463:Carbamide Peroxide; D003188:Composite Resins; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects*; D017220:Dentin-Bonding Agents; D004338:Drug Combinations; D006801:Humans; D008297:Male; D016877:Oxidants / Q000009:adverse effects*; D010545:Peroxides / Q000009:adverse effects*; D010865:Pilot Projects; D013718:Tensile Strength; D014073:Tooth Bleaching / Q000009:adverse effects*; D014508:Urea / Q000009:adverse effects* / Q000031:analogs & derivatives*
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D004338:Drug Combinations; C444701:Filtek Z250; D016877:Oxidants; D010545:Peroxides; C115612:single bond; D000077463:Carbamide Peroxide; D017438:Bisphenol A-Glycidyl Methacrylate; D014508:Urea