title: Effects of long-term water storage on the microtensile bond strength of five experimental self-etching adhesives based on surfactants rather than HEMA.
abstract: OBJECTIVE
  The purpose of this study is to evaluate the hypothesis that replacing 2-hydroxyethyl methacrylate (HEMA) for surfactant dimethacrylates (SD) does not affect the immediate and long-term microtensile bond strength (μTBS) of experimental two-step self-etch HEMA-free adhesive systems applied on dentin.
  
  
  METHODS
  Five experimental HEMA-free two-step self-etching systems containing different SD (ethoxylated bisphenol A diglycidyl dimethacrylate (Bis-EMA 10, B10), Bis-EMA 30 (B30), poly-ethyleneglycol (400) dimethacrylate (PEG 400, P400), PEG 1000 (P1000), and PEG 400 urethane dimethacrylate (UDMA) (UP400)) and a HEMA-containing system (control) (HA) were formulated. Specimens were subjected to the μTBS test after 24 h and 6 and 12 months of storage. Data (in megapascals) were analyzed by Kruskal-Wallis and Dunn tests (α = 0.05).
  
  
  RESULTS
  Medians of the μTBS data after 24 h of storage are: HA = 57.2(A), B10 = 26.2(BC), B30 = 24.0(C), P400 = 32.6(BC), P1000 = 37.3(B), and UP400 = 57.9(A); after 6 months are: HA = 47.9(A), B10 = 18.5(B), B30 = 7.8(C), P400 = 16.1(B), P1000 = 14.6(BC), and UP400 = 51.6(A); and after 12 months are: HA = 31.2(A), B10 = 15.2(B), B30 = 9.0(B), P400 = 9.1(B), P1000 = 13.3(B), and UP400 = 35.7(A). Between the HEMA-free groups, the adhesive system formulated with PEG 400 UDMA produced similar μTBS to the HEMA-containing group. Also, the storage of specimens decreased the μTBS (p < 0.05).
  
  
  CONCLUSIONS
  Replacing HEMA for PEG 400 UDMA in an adhesive system formulation generated a satisfactory μTBS to dentin.
  
  
  CONCLUSIONS
  Surfactant dimethacrylates have a potential use in the development of HEMA-free self-etching adhesive systems, which are more chemically stable.
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, Rua Gonçalves Chaves, 457, Pelotas, RS, Brazil, 96015-560. chzanchi@gmail.com
authors.forename: Cesar Henrique
authors.initials: CH
authors.lastname: Zanchi
authors.forename: Eliseu Aldrighi
authors.initials: EA
authors.lastname: Münchow
authors.forename: Fabrício Aulo
authors.initials: FA
authors.lastname: Ogliari
authors.forename: Rodrigo Varella
authors.initials: RV
authors.lastname: de Carvalho
authors.forename: Stefano
authors.initials: S
authors.lastname: Chersoni
authors.forename: Carlo
authors.initials: C
authors.lastname: Prati
authors.forename: Flávio Fernando
authors.initials: FF
authors.lastname: Demarco
authors.forename: Evandro
authors.initials: E
authors.lastname: Piva
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D003432:Cross-Linking Reagents; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004356:Drug Storage; D008689:Methacrylates / Q000737:chemistry*; D011092:Polyethylene Glycols; D019279:Resin Cements / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013501:Surface-Active Agents / Q000737:chemistry*; D013718:Tensile Strength; D014867:Water
chemical_list: D003432:Cross-Linking Reagents; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D013501:Surface-Active Agents; D014867:Water; D011092:Polyethylene Glycols; C005044:hydroxyethyl methacrylate