title: [Study of pretreatment with ethanol to compensate premature volatilization of self-etch adhesive system].
abstract: OBJECTIVE
  To evaluate the effect of pretreatment with ethanol on dentin to compensate premature volatilization of self-etch adhesive system.
  
  
  METHODS
  Thirty-two intact human molars were randomly divided into two groups using a table of random numbers (n = 16): A, an acetone-base adhesive (G-bond) and B, an ethanol-based adhesive (Clearfile S(3) bond). Then each group was randomly assigned into foursub groups (n = 4) : group 1, no premature volatilization; group 2, premature volatilization; group 3, premature volatilization + stepwise ethanol pretreatments; and group 4, premature volatilization + absolute ethanol treatment. After composite resin building, microtensile bond strengths (MTBS) of each subgroup were then tested. Fracture modes were classified by stereomicroscopy and representative interface was observed by field-emission scanning electron microscopy (FE-SEM).
  
  
  RESULTS
  For adhesive A, there was significant difference on MTBS among different subgroups (P < 0.05); the MTBS of group A2 [(26 ± 12) MPa] and A4 [(27 ± 7) MPa] was lower than that of group A1 [(41 ± 11) MPa] and A3 [(40 ± 11) MPa] (P < 0.05). No significant different was found between group A2 and A4 (P > 0.05); neither between group A1 and A3 (P > 0.05). For adhesive B, there was no difference on MTBS among different subgroups (P > 0.05).FE-SEM showed that the main fracture mode was located at the bottom of the hybrid layer for adhesive A groups, the collagen fibrils were capsulated by resin monomers more densely in group A1 and group A3 in comparison with other two subgroups.For adhesive B groups, the main failure modes were at the top of the hybrid layer.
  
  
  CONCLUSIONS
  Premature volatilization can obviously decrease the bonding strength of acetone-base self-etch adhesives, but has no significant effect on ethanol-based self-etch adhesives. Dentin pretreatment with a series of increasing ethanol concentrations can effectively compensate the adverse effect of premature volatilization of acetone-base self-etch adhesives on bonding strength.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Hongye
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Prosthodontics, School of Stomatology, Wuhan University, Wuhan 430079, China. Email: huangcui@whu.edu.cn.
authors.forename: Cui
authors.initials: C
authors.lastname: Huang
authors.forename: Donglai
authors.initials: D
authors.lastname: Deng
mesh_terms: D000269:Adhesives; D003188:Composite Resins; D001840:Dental Bonding; D003764:Dental Materials; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents; D000431:Ethanol / Q000737:chemistry*; D006801:Humans; D008689:Methacrylates; D008855:Microscopy, Electron, Scanning; D008963:Molar; D019279:Resin Cements; D013718:Tensile Strength; D014835:Volatilization
chemical_list: D000269:Adhesives; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C498353:G-Bond; D008689:Methacrylates; D019279:Resin Cements; D000431:Ethanol