Bonding effectiveness and interfacial characterization of a HEMA/TEGDMA-free three-step etch&rinse adhesive

OBJECTIVES: 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