title: Effect of enamel and dentin surface wetness on shear bond strength of composites.
abstract: OBJECTIVE
  This study investigated the effect of the wetness of human enamel and dentin surfaces on the shear bond strength of composites.
  
  
  METHODS
  Seven dentin bonding systems were used. Three methods of preparing the enamel or dentin surface before applying primer or bonding agent were adopted as test conditions: wet (blot dried), semidry (3-second air blast), and dry (15-second air drying). Shear bond strength was measured with a universal testing machine. Mean bond strengths were analyzed with analysis of variance and Scheffe's F-test. Enamel and dentin surfaces were observed by a dissecting microscope after shear bond testing.
  
  
  RESULTS
  Enamel specimens tested by all systems and dentin tested by two systems did not reveal significant differences in shear bond strengths (p > 0.05). Among dentin specimens tested by two systems with water-based primers, the shear bond strength values of the dry technique group were higher than those of the other two groups (p < 0.05). However, among dentin specimens tested by systems having acetone-based primers or bonding agents, bond strength values of the wet or semidry technique groups were higher than those of the dry technique group (p < 0.05).
  
  
  CONCLUSIONS
  It was concluded that some water might be needed by dentin surfaces or for primers to obtain high bond strength on the dentin surface, but that drying methods did not affect bonding strength to enamel surfaces either before priming or after conditioning.
authors.affiliation: Department of Conservative Dentistry, Osaka University Faculty of Dentistry, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Iwami
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Kawai
authors.forename: S
authors.initials: S
authors.lastname: Ebisu
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000706:statistics & numerical data; D003743:Dental Enamel / Q000187:drug effects*; D003804:Dentin / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D008334:Mandible; D008422:Materials Testing / Q000379:methods / Q000706:statistics & numerical data; D008437:Maxilla; D008963:Molar; D013314:Stress, Mechanical; D013499:Surface Properties; D017155:Wettability
chemical_list: D003188:Composite Resins