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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 +/- 0.2 mm diameter and 9.5 mm long were made and stored at 37 degrees C for 24 hours. The specimens were milled into dumb-bell shapes and stored in either air or water at 37 degrees C. Five specimens of each material were stressed in tension after the specified storage times at a crosshead speed of 1 mm/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.