Effect of Cavity Preparation Techniques on Composite-Resin/Dentin Interface – Sem Study

The bonding mechanism of current self-etching adhesive-systems consists of direct application over treated dentin by the cavity preparation techniques (CPT). Objectives: This study evaluated the effect of CPT on composite-resin/dentin interface, using self-etching adhesive-systems (Clearfil SE Bond – Kuraray (SE)/ Tyrian – Bisco (TY) / Unifil Bond – GC Corp (UN)) and a total-etch adhesive-system (Single Bond – 3M ESPE (SB)), by means of SEM analysis. Methods: Oclusal dentin flattened of third molars was treated with sonoabrasion (SA), Er:YAG laser (200mJ/4Hz) (LA) and 600-grit SiC paper (SiC). Twelve experimental groups were determined (n=4). Following each surface treatment, adhesive-systems were applied according to manufacturer's instructions and 5mm high blocks were incrementally built up with Clearfil AP-X (Kuraray) composite-resin. The specimens were stored for 24hrs in distilled water and teeth were serially sectioned in mesio-distal directions obtaining slabs of 2mm thick. Three central slabs were polished, fixed, critical-point dried and sputtered with gold before SEM analysis. Results: It was observed that teeth treated with LA showed thinner hybrid-layers (HL), with long tags when compared to SiC. For SA treatment HL was present with short tags. For SB, treatments with SA and SiC showed similar structures. Conclusion: SEM images suggests that CPT can influence the formation of the HL for the tested adhesive-systems.