The microtensile strength of bonding resins

Background: The purpose of this study was to determine the effect of water on the tensile strength of three bonding resins (All Bond 2, Scotchbond Multi-Purpose Adhesive, Clearfil LB Bond) and a low viscosity resin composite (Protect Liner F) after 1, 7, 28, 84 and 168 days of storage. Methods: Cylinders of bonding resin 2.4 +/-0.2mm diameter and 9.5mm long were made and stored at 37 degreesC for 24 hours. The specimens were milled into dumb-bell shapes and stored in either air or water at 37 degreesC. Five specimens of each material were stressed in tension after the specified storage times at a crosshead speed of 1mm/min in a testing jig attached to a universal testing machine. The mean tensile strengths of bonding resins were calculated and analysed statistically using one-way analysis of variance, lower standard deviation and student t-tests. Results: Comparison of the air and water samples at all test periods showed the tensile strengths of specimens stored in water were significantly less than those stored in air (P <0.001). Conclusion: The effect of water on the tensile strength of bonding resins indicated a slight decrease in strength of each material over the 168 day test period, whereas the air samples showed little change over the test period.