title: Ethanol-wet bonding and chlorhexidine improve resin-dentin bond durability: quantitative analysis using raman spectroscopy.
abstract: OBJECTIVE
  To directly test the effectiveness of ethanol-wet bonding (EW) in improving monomer infiltration into demineralized dentin through quantitative measurement of bis-GMA and TEG-DMA molar concentrations within hybrid layers, and to comprehensively evaluate the effect of EW and chlorhexidine on durability of resin-dentin bonds compared to conventional water-wet bonding (WW).
  
  
  METHODS
  A three-step etch-and-rinse adhesive (70% bis-GMA/28.75%TEG-DMA) was applied to coronal dentin using a clinically relevant ethanol-wet bonding protocol (EW) or the conventional water-wet bonding (WW) technique. Bis-GMA and TEG-DMA molar concentrations at various positions across the resin/dentin interfaces formed by EW and WW were measured using micro-Raman spectroscopy. The experiment was repeated at the same positions after 7-month storage in phosphate buffer solution containing 0.1% sodium azide. The μTBS and hybrid layer morphology (TEM) of bonding groups with and without chlorhexidine application were compared immediately and after 1-year storage in terms of nanoleakage, collagen fibril diameter, collagen interfibrillar width, and hybrid layer thickness.
  
  
  RESULTS
  Specimens bonded with EW showed significantly higher monomer molar concentrations and μTBS throughout the hybrid layer immediately and after storage, providing direct evidence of superior infiltration of hydrophobic monomers in EW compared to WW. Microscopically, EW maintained interfibrillar width and hybrid layer thickness for resin infiltration and retention. The application of chlorhexidine further preserved collagen integrity and limited the degree of nanoleakage in EW after 1-year storage.
  
  
  CONCLUSIONS
  EW enhances infiltration of hydrophobic monomers into demineralized dentin. The results suggest that a more durable resin-dentin bond may be achieved with combined usage of a clinically relevant EW and chlorhexidine.
authors.forename: Supitcha
authors.initials: S
authors.lastname: Talungchit
authors.forename: Julie L P
authors.initials: JL
authors.lastname: Jessop
authors.forename: Deborah S
authors.initials: DS
authors.lastname: Cobb
authors.forename: Fang
authors.initials: F
authors.lastname: Qian
authors.forename: Saulo
authors.initials: S
authors.lastname: Geraldeli
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Steven R
authors.initials: SR
authors.lastname: Armstrong
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002710:Chlorhexidine / Q000737:chemistry*; D003094:Collagen / Q000648:ultrastructure; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003763:Dental Leakage / Q000145:classification; D003764:Dental Materials / Q000737:chemistry*; D003804:Dentin / Q000648:ultrastructure*; D000431:Ethanol / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D061965:Matrix Metalloproteinase Inhibitors / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D061965:Matrix Metalloproteinase Inhibitors; D011109:Polymethacrylic Acids; D012997:Solvents; C083568:Z100 composite resin; D014867:Water; C020946:triethylene glycol dimethacrylate; D000431:Ethanol; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D003094:Collagen; D015040:Zirconium; D002710:Chlorhexidine