Effect of condensation techniques on amalgam bond strengths to dentin

This in vitro study determined the shear bond strengths of Tytin amalgam to dentin using All-Bond 2, Amalgambond Plus, Amalgambond Plus with HPA powder, and OptiBond with hand and mechanical (Condensaire) condensation. The occlusal enamel surfaces were ground flat to expose the dentin surfaces, and polished with 600-grit SiC paper. The dentin surfaces were treated with one of the combinations of a dentin bonding agent and a condensation technique. All specimens were thermocycled 300 cycles in water between 5-55 degrees C, and shear bond strengths were determined with a Zwick Universal Testing Machine. Two-way ANOVA and Duncan's tests showed no significant differences (P > 0.05) in shear bond strength between hand and mechanical condensation of the paired groups, with the exception of Amalgambond Plus, where hand condensation was shown to be significantly better. For both condensation techniques, shear bond strength of Amalgambond Plus with HPA powder was significantly higher than the other materials. For mechanical condensation, OptiBond was significantly higher than either Amalgambond Plus or All-Bond 2, and no significant difference was found between Amalgambond Plus and All-Bond 2. For hand condensation, OptiBond was only significantly higher than All-Bond 2, while there was no significant difference between OptiBond and Amalgambond Plus or between Amalgambond Plus and All-Bond 2. In conclusion, for both condensation techniques, Amalgambond Plus with HPA powder performed the best in bonding amalgam to dentin. The two different condensation techniques did not significantly affect shear bond strength, except with Amalgambond Plus.