DENTIN BOND EFFICACY OF COMPOSITE RESIN RESTORATIONS USING RESIN INFILTRANT

Aim: To evaluate the bond efficacy of direct resin composite restorations bonded by three different dentin adhesives an etch-and-rinse, self-etch and resin infiltrant (ICON) using microtensile bond strength testing and Analyze their failure mode.
Methodology: Thirty molar teeth were selected and thoroughly cleaned. Each tooth was vertically embedded into self-curing acrylic resin up to the level of the cervical line. The occlusal enamel of teeth was removed perpendicular to the long axis of teeth to expose flat dentin surface at a standardized depth. The teeth were divided into three main groups of 10 teeth each; using Etch and rinse adhesive system control group A1 (All-bond Universal, Bisco), self-etch adhesive system group A2 (All-bond Universal, Bisco) and resin infiltrant group A3 (Icon). Direct resin composite nano-hybrid universal composite (FiltekTM Z250 XT, 3M ESPE) cores were build up on the flat dentin surfaces treated with different adhesive systems. The restored teeth were subjected to thermo-cycling at 5°C and 55°C for 2000cycle. Then each tooth was mounted on the cutting machine, sectioned into a series of 1 mm thick. The sticks were stressed to failure under tension using Universal Testing Machine to record the microtensile bond strength. The fractured sticks were evaluated for bond failure mode under a stereomicroscope at 40X magnification to detect the mode of failure. The collected data were submitted to ANOVA and Tukey’s test.
Results: Etch-and-rinse (A1) control group showed the highest significant mean Microtensile bond strength (MPa) followed by Self-etch adhesive (A2) followed by Resin infiltrant (ICON) (A3) at p≤0.001. The result of the stereomicroscopic examination revealed adhesive and cohesive failure mode in composite. The predominant mode of failure using resin infiltrant group A3 (Icon) and self-etch adhesive system group A2 group was adhesive failure with a higher percentage in resin infiltrant A3 (Icon) group 100%. On the other hand cohesive in composite is the predominant mode of failure using the Etch and rinse adhesive system group A1 80%.
Conclusion: The use of resin infiltrant (Icon) as an adhesive material impaired efficacy of the microtensile bond strength of direct resin composite to sound dentin .