Abstract
The aims of this study were to determine the mean shear bond strength of fast setting fluoride releasing core materials (vitremer core build up restorative system,compoglass F resin modified glass ionomer,Tetricceram composite and Definite composite) to dentin and the effect of one hour, 24 hour, and one week storage on mean shear bond strength. One hundred thirty molar teeth Were mounted in a plastic cylinder using self-curing resin, then the teeth were prepared to expose flat superficial dentinal surfaces. Each material was mixed according to the manufacturer ' s instruction ' s. A prefabricated nylon mold was applied to the exposed denton, filled with the core material, then light cured and stored in distilled water at 37°C for one hour, 24 hours and one week. The 24 hours and one week storage groups were thermocycled(5°C to 55°C) for 100 cycles before shearing, The specimen were tested with universal compression machine and the mode of failure was observed. The result showed that Vitrether core build up exhibited the greatest bond strength followed by compoglass F and then Tetrie Composite, Definite showed the lowest for all storage time. The differences among time groups were not statistically significant except for vitremer core build up and compoglass F which showed an improvement after 24 hour storage. The adhesive mode of failure revealed a combination of cohesive adhesive failure and failure for vitremer core build up and compoglass F and adhesive failure for Tetricceram and Definite composite resin.
