EDTA or H3PO4/NaOCl dentine treatments may increase hybrid layers' resistance to degradation: A microtensile bond strength and confocal-micropermeability study

Salvatore Sauro, Francesco Mannocci, Manuel Toledano, Raquel Osorio, David H. Pashley, Timothy F. Watson

Research output: Contribution to journalArticle

47 Scopus citations


Objectives: The aim of this study was to reduce hybrid layer degradation created with simplified dentine adhesives by using two different methods to condition the dentine surface. Methods: A smear-layer was created on flat dentine surfaces from extracted human third molars with a 180-grit/SiC-paper. Dentine specimens were conditioned before bonding with the following procedures: 37% H3PO4; H3PO4/0.5% NaOCl; 0.1 M EDTA; 0.1 M EDTA/0.5% NaOCl. Two etch-and-rinse adhesives: (Scotchbond 1XT or Optibond Solo Plus) were applied and light-cured. Composite build-ups were constructed. The bonded teeth were sectioned into beams, stored in distilled water (24 h) or 12% NaOCl solution (90 min) and finally tested for microtensile bond strengths (μTBS). Additional dentine surfaces were conditioned and bonded as previously described. They were prepared for a pulpal-micropermeability confocal microscopy study and finally observed using confocal microscopy. Results: μTBS results revealed that both adhesives gave high bond strengths to acid-etched dentine before, but not after a 12% NaOCl challenge. Bonds made to acid-etched or EDTA-treated dentine plus dilute NaOCl, gave high μTBS that resisted 12% NaOCl treatment, as did EDTA-treated dentine alone. A confocal micropermeability investigation showed very high micropermeability within interfaces of the H3PO4, etched specimens. The lowest micropermeability was observed in H3PO4 + 0.5% NaOCl and 0.1 M EDTA groups. Conclusions: The use of dilute NaOCl (0.5%) after acid-etching, or the conditioning of dentine smear layers with 0.1 M EDTA (pH 7.4) produced less porous resin-dentine interfaces. These dentine-conditioning procedures improve the resistance of the resin-dentine bond sites to chemical degradation (12% NaOCl) and may result in more durable resin-dentine bonds.

Original languageEnglish (US)
Pages (from-to)279-288
Number of pages10
JournalJournal of Dentistry
Issue number4
Publication statusPublished - Apr 1 2009



  • Adhesion
  • Chemical degradation
  • EDTA
  • Etch-and-rinse dental adhesive
  • Hybrid layer
  • NaOCl

ASJC Scopus subject areas

  • Dentistry(all)

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