title: [Effect of base layer thickness of a self-adhesive resin on dentin bonding strength].
abstract: OBJECTIVE
  To evaluate the effect of base layer thickness of DyadFlow(DF) self-adhesive resin on dentin bonding strength.
  
  
  METHODS
  Twenty extracted intact human molars were randomly selected and the occlusal surface of each molar was prepared by removing the enamel and exposing the dentin surface. The prepared molars were divided, randomly and equally, into 4 groups. For groups G0.5, G1.0 and G2.0, DF was applied directly on the dentin surfaces following the manufacturer's instruction, and for group GOB, OptiBond All-in-One(OB) self etching adhesive was applied on the dentin surface before using DF. The base layer thickness of DF was 0.5 mm, 1.0 mm, 2.0 mm, 2.0 mm for groups G0.5, G1.0, G2.0 and GOB, respectively. Composite crown were built up on each tooth, then the samples were sectioned longitudinally into sticks with proximately 1.0 mm2 bonding area(for microtensile bond strength[MTBS] testing) or slabs (for bonding interface observation with SEM). Fifteen sticks were obtained for each group. The fracture surface was also observed using SEM and the fracture type of each specimen was determined.
  
  
  RESULTS
  The MTBS were: GOB (20.19±3.11) MPa>G0.5 (8.65±1.58) MPa>G1.0 (6.65±1.13) MPa>G2.0 (5.70±0.60) MPa(P<0.05). Bonding interface fracture B2 was most frequently observed for all groups: G0.5: 14/15, G1.0: 13/15, G2.0: 14/15 and GOB: 13/15.
  
  
  CONCLUSIONS
  The MTBS decreased when the base layer thickness of DF increased. Direct application of DF self-adhesive resin on dentin surface adhesive restorations should be concerned.
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Zhaoran
authors.initials: Z
authors.lastname: Fu
authors.lastname: CaiXue
authors.forename: Fucong
authors.initials: F
authors.lastname: Tian
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wang
mesh_terms: D000269:Adhesives / Q000737:chemistry; D003442:Crowns; D001840:Dental Bonding; D003743:Dental Enamel; D003804:Dentin / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008963:Molar; D019279:Resin Cements / Q000737:chemistry; D013718:Tensile Strength
chemical_list: D000269:Adhesives; D017220:Dentin-Bonding Agents; C092987:Optibond; D019279:Resin Cements