title: Effect of dimethyl sulfoxide wet-bonding technique on hybrid layer quality and dentin bond strength.
abstract: OBJECTIVE
  This study examined the effect of a dimethyl sulfoxide (DMSO) wet bonding technique on the resin infiltration depths at the bonded interface and dentin bond strength of different adhesive systems.
  
  
  METHODS
  Flat dentin surfaces of 48 human third molars were treated with 50% DMSO (experimental groups) or with distilled water (controls) before bonding using an etch-and-rinse (SBMP: Scotchbond Multi-Purpose, 3M ESPE) or a self-etch (Clearfil: Clearfil SE Bond, Kuraray) adhesive system. The restored crown segments (n=12/group) were stored in distilled water (24h) and sectioned for interfacial analysis of exposed collagen using Masson's Trichrome staining and for microtensile bond strength testing. The extent of exposed collagen was measured using light microscopy and a histometric analysis software. Failure modes were examined by SEM. Data was analyzed by two-way ANOVA followed by Tukey Test (α=0.05).
  
  
  RESULTS
  The interaction of bonding protocol and adhesive system had significant effects on the extension of exposed collagen matrix (p<0.0001) and bond strength (p=0.0091). DMSO-wet bonding significantly reduced the extent of exposed collagen matrix for SBMP and Clearfil (p<0.05). Significant increase in dentin bond strength was observed on DMSO-treated specimens bonded with SBMP (p<0.05), while no differences were observed for Clearfil (p>0.05).
  
  
  CONCLUSIONS
  DMSO-wet bonding was effective to improve the quality of resin-dentin bonds of the tested etch-and-rinse adhesives by reducing the extent of exposed collagen matrix at the base of the resin-dentin biopolymer. The improved penetration of adhesive monomers is reflected as an increase in the immediate bond strength when the DMSO-wet bonding technique is used with a water-based etch-and-rinse adhesive.
authors.affiliation: Piracicaba Dental School, University of Campinas - UNICAMP, Department of Restorative Dentistry, Av. Limeira 901, Piracicaba, SP 13414-903, Brazil. Electronic address: thiagohs@hotmail.com.
authors.forename: Thiago Henrique Scarabello
authors.initials: TH
authors.lastname: Stape
authors.affiliation: Institute of Dentistry, University of Oulu, and Medical Research Center Oulu, Oulu University Hospital, PO Box 5281, 90014 University of Oulu, Finland; Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki University Hospital, Helsinki, Finland. Electronic address: leo.tjaderhane@oulu.fi.
authors.forename: Leo
authors.initials: L
authors.lastname: Tjäderhane
authors.affiliation: Piracicaba Dental School, University of Campinas - UNICAMP, Department of Morphology, Av. Limeira 901, Piracicaba, SP 13414-903, Brazil. Electronic address: marques_fop@hotmail.com.
authors.forename: Marcelo Rocha
authors.initials: MR
authors.lastname: Marques
authors.affiliation: Piracicaba Dental School, University of Campinas - UNICAMP, Department of Restorative Dentistry, SP 13414-903, Brazil. Electronic address: aguiar@fop.unicamp.br.
authors.forename: Flávio Henrique Baggio
authors.initials: FH
authors.lastname: Aguiar
authors.affiliation: Piracicaba Dental School, University of Campinas - UNICAMP, Department of Restorative Dentistry, SP 13414-903, Brazil. Electronic address: martins@fop.unicamp.br.
authors.forename: Luís Roberto Marcondes
authors.initials: LR
authors.lastname: Martins
mesh_terms: D001840:Dental Bonding; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D019279:Resin Cements; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D004121:Dimethyl Sulfoxide
keywords: Collagen; Etch-and-rinse adhesive; Microtensile bond strength, DMSO; Resin infiltration; Resin–dentin biopolymer; Self-etch adhesive