IADR Miami 2009 location:Miami date:1-4 april 2009
It was in the line of expectations that the success of self-adhesive composite cements would soon lead to the development of self-adhesive restorative composites that are bonded to tooth enamel and dentin without a separate adhesive. Objectives: to characterize using TEM the interaction of a self-adhesive flowable composite (Vertise Flow, Kerr) with enamel/dentin. Methods: The adhesive-free composite was applied to bur-cut (medium-grit: 100 µm) enamel, and to fractured (smear-free), 600-grit SiC-paper ground, and bur-cut dentin, first in a thin layer (<1 mm) using the bendable mini-brush with agitation for 15 sec, followed by 20-sec light-curing, and application of a second increment (<2 mm) and again 20-sec light-curing. Non-demineralized/demineralized 70-90 nm sections were prepared following common TEM-specimen processing procedures, including fixation, gradual dehydration, embedding, and diamond-knife ultra-microtomy. Results: The flowable composite showed a typical micro-hybrid filler distribution. At bur-cut enamel, a tight interface was formed, mostly with only tiny micro-tags and without distinct dissolution of hydroxyapatite observable. At fractured dentin, a relatively thin hybrid layer of maximum a few hundreds of nanometer was formed without clear surface demineralization. At SiC-ground and bur-cut dentin, the interaction of the adhesive-free composite appeared very superficial, with the surface structure being more irregular in case of bur preparation. No clear resin tags were formed due to the obstruction of dentin tubules with smear plugs. Conclusion: The obtained tight interface at both enamel and dentin demonstrates the self-adhesive capacity of the adhesive-free flowable composite.