title: Bonding effectiveness and interfacial characterization of a HEMA/TEGDMA-free three-step etch&rinse adhesive.
abstract: OBJECTIVE
  Small and hydrophilic monomers as HEMA and TEGDMA can easily penetrate human tissues. For biocompatibility issues it is therefore better to avoid such monomers in dental adhesive formulations. The purpose of this study was (1) to determine the micro-tensile bond strength (muTBS) to enamel/dentin of a HEMA/TEGDMA-free three-step etch&rinse adhesive (cmf Adhesive System, Saremco), and (2) to characterize it's interfacial interaction with enamel/dentin using transmission electron microscopy (TEM).
  
  
  METHODS
  Twelve intact freshly extracted human third molars were used for muTBS. The three-step etch&rinse adhesive OptiBond FL (Kerr) served as control adhesive. After bonding procedures and subsequent composite build-up (Z100, 3M ESPE), specimens were sectioned to sticks and trimmed at the interface to a cylindrical hour-glass shape. TEM section of non-demineralized and demineralized sections were prepared by ultra-microtomy and examined.
  
  
  RESULTS
  The muTBS of the cmf Adhesive System to enamel was not statistically significantly different from that of the control (OptiBond FL) adhesive (p=0.3512); the muTBS to dentin was however significantly lower (p<0.0001). TEM showed a tight interface at enamel for both adhesives. A relatively thick, completely demineralized and acid-resistant hybrid layer was formed at dentin. Some degree of spot- and cluster-like nano-leakage was observed with cmf Adhesive System, but did not differ in extent and form in comparison to that observed with the OptiBond FL control.
  
  
  CONCLUSIONS
  The new three-step adhesive cmf Adhesive System showed indications of good bonding effectiveness, certainly to enamel and only significantly lower to dentin, when compared to the gold-standard adhesive. The latter may be related to the adapted HEMA/TEGDMA-free formulation and the somewhat lower mechanical properties.
authors.affiliation: Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Mine
authors.forename: Jan
authors.initials: J
authors.lastname: De Munck
authors.forename: Kirsten L
authors.initials: KL
authors.lastname: Van Landuyt
authors.forename: André
authors.initials: A
authors.lastname: Poitevin
authors.forename: Takuo
authors.initials: T
authors.lastname: Kuboki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Paul
authors.initials: P
authors.lastname: Lambrechts
authors.forename: Bart
authors.initials: B
authors.lastname: Van Meerbeek
mesh_terms: D000134:Acid Etching, Dental; D003432:Cross-Linking Reagents / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure*; D018772:Dental Marginal Adaptation; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects / Q000648:ultrastructure*; D006801:Humans; D008689:Methacrylates / Q000737:chemistry; D008964:Molar, Third; D019279:Resin Cements / Q000737:chemistry*; D013718:Tensile Strength
chemical_list: D003432:Cross-Linking Reagents; D003738:Dental Cements; D008689:Methacrylates; D019279:Resin Cements; C005044:hydroxyethyl methacrylate; C004919:ethylene dimethacrylate