Journal of Dental Research vol:87 issue:Spec Iss B
annual meeting of IADR-Continental European and Israeli Divisions edition:42 location:Thessaloniki date:26-29, Sept 2007
Objectives: The new three-step adhesive 'cmf adhesive system' (CMF, Saremco) is free of co-monomers such as TEGDMA and HEMA for biocompatibility reasons, for instance in prevention of allergic reactions of patients and dental staff. The purpose of this study was 1) to determine the micro-tensile bond strength (µTBS) to enamel/dentin, and 2) to characterize its interfacial interaction with enamel/dentin using transmission electron microscope (TEM).
Methods: Twelve intact freshly extracted human third molars were used for µTBS. Optibond FL (OBFL, Kerr) served as control. After bonding procedures following the respective manufacturer's instructions and subsequent composite build-up (Z100, 3M ESPE), specimens were sectioned to 1.8x1.8 mm sticks and trimmed at the interface to a cylindrical hour-glass shape (±1.2 mm) using the MicroSpecimen Former (University of Iowa). TEM non-demineralised and demineralised sections, and sections of specimens immersed in ammoniacal silver nitrate were prepared by ultra-microtomy and examined (EM 900, Zeiss).
TEM showed a tight interface at enamel. The etch-pits produced by the 'mild' phosphoric-acid conditioner (pH=1.5) were rather shallow, but resulted in clearly defined micro-tags. A relatively thick, completely demineralised and acid-resistant hybrid layer was formed, varying in thickness between 1.5-3 µm at dentin. The dentin tubules were opened and enabled the formation of resin tags. Some degree of spot and cluster-like nanoleakage was observed, but did not differ in extent and form in comparison to that observed with the OBFL control.
Conclusion: The new three-step adhesive 'cmf adhesive system' showed clear indications of good bond reliability.