title: The influence of intrinsic water permeation on different dentin bonded interfaces formation.
abstract: OBJECTIVE
  To determine the effects of intrinsic wetness on the formation of dentin bonding interfaces of four resin cement systems bonded to dentin under different pulpal pressures.
  
  
  METHODS
  Thirty-six freshly extracted third molars were selected and processed for dentin μTBS. The teeth were randomly assigned into 12 experimental groups, according to the adhesive luting system [Adper Single Bond Plus (3M ESPE) combined with two luting agents RelyX ARC (3M ESPE) and heated Filtek Z250 Universal Restorative (3M ESPE), Clearfil CD Bond (Kuraray) combined with Clearfil Esthetic Cement (Kuraray), and RelyX Unicem 2 Automix (3M ESPE)] and pulpal pressure (0, 5, and 20 cm of simulated pulpal pressure). Leucite-reinforced glass-ceramic slabs (IPS Empress CAD, Ivoclar Vivadent) of 3mm thickness were bonded to dentin. The samples were stored in distilled water for 24h and then sectioned in X/Y directions across the adhesive interface to obtain specimens with a cross section of 0.8 ± 0.2mm(2). All sticks were fractured by tension at a crosshead speed of 1.0mm/min and the data were submitted to Kruskal-Wallis and Mann-Whitney Tests (α=0.05). Ultrastructural analysis of the interfaces was performed using Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM).
  
  
  RESULTS
  The statistical analyses showed that pulpal pressure decreased μTBS for all groups. Significantly higher μTBS values were obtained in heated Z250 group restored without any pulpal pressure. CLSM showed that the uptake of water through the dentin tubuli and their anastomosis of lateral branches during the adhesive luting procedures prevented adequate formation of the dentin bonding interfaces. SEM showed that the luting film created is material- dependent and all adhesive failure occurred at the resin-dentin interface.
  
  
  CONCLUSIONS
  The constant intrinsic wetness replenishment prevents adequate formation of the hybrid layer.
  
  
  CONCLUSIONS
  Intrinsic moisture during adhesive luting procedures significantly affects the interaction between luting materials and dentin subtract and decreases the quality and bonding strength of the resin-dentin bond.
authors.affiliation: Ostrow School of Dentistry of University of Southern California, Division of Restorative Sciences, Los Angeles, CA, USA. Electronic address: sartori@usc.edu.
authors.forename: Neimar
authors.initials: N
authors.lastname: Sartori
authors.affiliation: Ostrow School of Dentistry of University of Southern California, Division of Restorative Sciences, Los Angeles, CA, USA.
authors.forename: Lais Dalmagro
authors.initials: LD
authors.lastname: Peruchi
authors.affiliation: Ostrow School of Dentistry of University of Southern California, Division of Restorative Sciences, Los Angeles, CA, USA.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Phark
authors.affiliation: Ostrow School of Dentistry of University of Southern California, Division of Restorative Sciences, Los Angeles, CA, USA.
authors.forename: Sillas
authors.initials: S
authors.lastname: Duarte
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D003799:Dental Stress Analysis; D003804:Dentin / Q000000981:diagnostic imaging / Q000648:ultrastructure*; D003806:Dentin Permeability / Q000502:physiology; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008964:Molar, Third; D019279:Resin Cements / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: C029849:Clearfil Bonding Agent; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C511238:Single Bond Plus; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: Bond strength; Confocal scanning laser microscopy; Degradation; Dentin bonding agents; Dentin permeability; Ethanol; Ethanol-wet bonding; Hybrid layer; Pulpal pressure; Resin cements