title: Effect of polyacrylic acid on the interface and bond strength of self-adhesive resin cements to dentin.
abstract: OBJECTIVE
  To examine the influence of 11.5% polyacrylic acid pretreatment on the interface and bond strength of self-adhesive resin cements (Maxcem Elite, RelyX Unicem, SeT) to dentin.
  
  
  METHODS
  Fifty-six third molars were randomly divided into seven groups: RelyX ARC as control (ARC), RelyX Unicem (RLXU), Maxcem Elite (MCE), SeT (ST), polyacrylic acid+RelyX Unicem (RLXU-P), polyacrylic acid+Maxcem Elite (MCE-P), and polyacrylic acid+SeT (ST-P). Resin composite blocks were luted to flat dentin. After storage in distilled water for 24 h, sticks with a cross-sectional area of ca 0.80 mm2 were obtained (n = 24 per group) and submitted to a microtensile bond strength (µTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min. Two sets from each group were sectioned mesiodistally in the center of the crown and observed with a scanning electron microscope at 4000X magnification.
  
  
  RESULTS
  The mean results of the µTBS test (MPa) followed by the same letter do not differ statistically significantly according to ANOVA and Tukey's post-hoc test (p < 0.05): ARC = 24.19 (± 6.90)a, RLXU-P = 23.12 (± 6.18)a, MCE-P = 13.09 (± 5.87)b, RLXU = 10.23 (± 2.88)b,c, and MCE = 8.14 (± 4.63)c. All SeT specimens failed during the cutting procedure. The hybrid layer was not observed for the self-adhesive resin cements, and resin tags were observed for RelyX Unicem and Maxem Elite when dentin was pretreated with polyacrylic acid.
  
  
  CONCLUSIONS
  Pretreatment with 11.5% polyacrylic acid was effective for bonding RelyX Unicem and Maxcem Elite to dentin.
authors.affiliation: Department of Restorative Dentistry, Pontifical Catholic University of Rio Grande do Sul, Brazil.
authors.forename: Priscila
authors.initials: P
authors.lastname: Stona
authors.forename: Gilberto Antonio
authors.initials: GA
authors.lastname: Borges
authors.forename: Marcos Antônio
authors.initials: MA
authors.lastname: Montes
authors.forename: Luiz Henrique
authors.initials: LH
authors.lastname: Júnior
authors.forename: João Batista
authors.initials: JB
authors.lastname: Weber
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Spohr
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000180:Acrylic Resins / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; C515955:Maxcem; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; D014867:Water; C029824:urethane dimethacrylate luting resin; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C006903:carbopol 940