Evaluation of a novel dentin bonding system compared to commercial bonding system

Objective. The aim of the current study was to compare the bond strength of an experimental bonding system with commercial bonding systems. Material and methods. An aqueous solution of 10% ascorbic acid and 5% ferric chloride was prepared as an experimental conditioner (Exp). The flattened human dentin surfaces were conditioned with phosphoric acid, NaOCl, and Exp. They were bonded to a stainless steel rod with 4-META/MMA-TBB resin. Super-Bond C&B (10-3), Panavia Fluoro Cement (Panavia), Panavia Fluoro Cement with AD gel (AD/Panavia), and All-Bond 2 system (All-Bond 2) were also used. After immersion in water for 24 h, half of the specimens of each group were tested for tensile bond strength, and the remaining specimen groups were subjected to 10,000 cycles of thermo-cycling prior to tensile testing. All of the data were analysed by ANOVA and a post hoc test. In addition, two thermo-cycled specimens (10-3/10,000, Exp/10,000) were prepared for photomicrography. Results. The bond strengths of Exp and AD/Panavia groups showed no decrease after 10,000 thermo-cycles, although those of 10-3, Panavia, and All-Bond groups decreased significantly after thermo-cycling. SEM micrographs exhibited that cracks and voids can be observed in the 10-3/10,000 specimen at the interface of the adhesive resin and the hybrid layer, although neither a hybrid layer nor cracks can be seen in the Exp/10,000 specimen. Conclusion. Comparison of the tensile bond strengths for all adhesive resins revealed that the novel dentin bond system with experimental conditioner and Panavia Fluoro Cement with AD gel exhibited the most durable bonding after thermo-cycling.