Abstract
Introduction. the study aims at investigating the microtensile bond strength of composite repairing using a universal adhesives agent and at comparing it to 2-step Etch & Rinse adhesives with or without silane coupling treatment Materials and methods. 20 blocks of resin composite were fabricated then subjected to thermocycling, followed by air-abrasion with 50 mu m Al2O3. The blocks were divided randomly into ten groups, then assigned to five dental adhesives: Etch and Rinse Adhesive Single-Bond2 (SB2) and four different universal adhesives: Futurabond M+, Single-Bond Universal, Tetric-N-Bond- Universal, and Prime and Bond Universal with or without silane application. After surface treatment, the adhesive was applied, then fresh composite resin blocks were built on at 2 mm layer increments. The bonded blocks were sectioned to obtain beams with 1.0 mm2 cross-section. A micro-tensile bond strength testing using Universal Testing Machine was utilized for the specimens and a stereomicroscope was used to evaluate the fracture mode. Results and discussion. There was a significant difference in micro- tensile bond strength between all universal adhesives compared to the Etch and Rinse adhesive (SB2) without using silane. The application of silane resulted in a significant increase only with Etch and Rinse adhesive SB2, G1 (21.56 MPa) and G2 (37.11MPa) (P > 0.05), while other groups were not significantly affected. Conclusions. When adhesives were used without silane, Universal adhesives had a stronger micro-tensile bond compared to the SB2 the 2-step Etch&Rinse adhesive. Silane application enhanced significantly only the 2- step Etch&Rinse adhesive group.