title: [Influence of thermalcycling on bonding durability of self-etch adhesives with dentin].
abstract: OBJECTIVE
  To investigate influence of thermalcycling on the bonding durability of two one-step products [Adper Prompt (AP) and G-bond (GB)] and one two-step self-etching adhesive [Clearfil SE bond (SE)] with dentin in vitro.
  
  
  METHODS
  Forty-two extracted human molars were selected. The superficial dentin was exposed by grinding off the enamel. The teeth were randomly distributed into six groups with varied bonding protocols. The adhesives were applied to the dentin surface. Composite crowns were built up, then the samples were cut longitudinally into sticks with 1.0 mm×1.0 mm bonding area [for microtensile bond strength (MTBS) testing] or 1.0 mm thick slabs (for nanoleakage observation). Bonding performance was evaluated with or without thermalcyling. For the MTBS testing, the strength values were statistically analysed using One-Way ANOVA. Four slabs in each group were observed for nanoleakage by SEM with a backscattered electron detector.
  
  
  RESULTS
  Thermalcycling procedures affected MTBS. In the two one-step groups, the MTBS decreased significantly (P<0.05) after thermalcycling [AP group from (19.06±1.50) MPa to (12.62±2.10) MPa; GB group from (17.75±1.10) MPa to (6.24±0.42)MPa]. But in SE groups, MTBS did not significantly affect [(45.80±2.97) MPa compared with(40.60±5.76) MPa]. As a whole, one-step self-etching adhesives showed lower MTBS than two-step bonding system after aging.For AP and GB, continuous nanoleakage appearance was notable and more obvious than for SE.
  
  
  CONCLUSIONS
  Thermalcycling can affect the bonding performance of self-etch adhesives including decrease of bond strength and nanoleakage pattern. one-step self-etch adhesives showed more obvious change compared with their two-step counterparts.
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Fu-cong
authors.initials: FC
authors.lastname: Tian
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Xue-jun
authors.initials: XJ
authors.lastname: Gao
mesh_terms: D000269:Adhesives; D017438:Bisphenol A-Glycidyl Methacrylate; D001840:Dental Bonding; D003743:Dental Enamel; D003804:Dentin; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D010755:Organophosphates; D019279:Resin Cements; D013718:Tensile Strength
chemical_list: D000269:Adhesives; C489661:Adper Prompt Self-Etch; C438313:Clearfil SE Bond; C498353:G-Bond; D008689:Methacrylates; D010755:Organophosphates; D019279:Resin Cements; D017438:Bisphenol A-Glycidyl Methacrylate