In vitro Study of the Structure and Adhesive Interface in Direct Restorations with Experimental Nanocomposite Materials and Adhesive Systems

Using nanotechnology to produce composite materials it has been possible to obtain materials with similar or better mechanical properties than previous generation of microhybrids, and with exceptional aesthetics and chandelier due to the particularities of nanomaterials. At the same time, the improvement of adhesive techniques to enamel and dentin allowed the expansion of the area of direct composite restorations with a better prognostic over time. Eight cane-free molars were used and each of them was prepared with two class II cavities, which were filled using the C13 and C20 nanocomposites and the A1 and A2 experimental adhesive systems prepared at the Raluca Ripan Chemistry Research Institute. The teeth were divided into four groups of two teeth each, depending on the adhesive system and the composite material used. Scanning electron microscopy images (SEM) have described the adhesive interface and structure characteristics for the two nanocomposite materials and for the two studied adhesive systems. The studied nanocomposites have a variable number of porosities and air bubbles, with a clinical importance which is yet hard to establish. The experimental adhesives used produce a good interface and infiltration of the smear-layer but have not been visualized inside the dentinal canals. In vitro studies are necessary to evaluate the durability of adhesion in the case of self-etch adhesives in one or two steps.