Effect of thermo-cycling on resin cement shear bond strength

Objectives : Repeated exposure to cyclic temperatures can result in change of bond strength. The purpose of this study is to determine the difference in shear bond strengths between a standard 24-h test and a 4000×-thermo-cycle (TC) test for a range of resin cements and bonding substrates using a newly developed shear bond strength testing rig assembly.

Materials and methods : Rexillium III (Pentron) and Vitabloc ® (Vita Zahnfabrik) samples were sand blasted using 50-μm alumina, then washed with ethanol and dried. Cement was mixed in accordance with manufacturers’ instructions and applied to one end of a 4 mm diameter × 5 mm long acrylic rod. The rod was inserted into a thin walled stainless steel tube with 3.5 mm ID held onto the substrate by a self-aligning rig. A 400 g load was placed on the rod for 15 s after which samples were placed in an incubator (37 °C, 100% relative humidity). After 1 h the samples were removed from the rigs and stored in water (37 °C) for 24 h. Shear bond strengths were taken by forcing the bonded mold assembly off the substrate. The thermo-cycled test followed the same methodology as the 24-h test except for an additional step whereby each sample was cycled between 5 and 55 °C water baths for 4000 cycles.

Results:

seT PP G-cem automix Maxcem Elite RelyX Clicker
24 h TC 24 h TC 24 h TC 24 h TC
Rexillium 11.42 (2.15) 7.29 (2.25) 11.40 (2.35) 7.88 (1.50) 12.73 (1.66) 7.75 (3.05) 12.92 (1.47) 8.50 (0.35)
Bovine enamel 6.99 (1.26) 8.19 (1.06) 7.91 (0.69) 7.10 (0.84) 7.58 (0.76) 7.58 (0.76) 7.96 (1.01) 2.08 (1.50)
Vitabloc MKII 9.25 (2.60) 12.55 (1.87) 11.61 (6.01) 15.14 (5.85) 8.29 (1.55) 12.38 (3.60) 14.26 (2.04) 10.42 (1.80)
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Nov 30, 2017 | Posted by in Dental Materials | Comments Off on Effect of thermo-cycling on resin cement shear bond strength
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