Effect of long-term water storage on dentin bonding

To determine the effect of long term water storage on assembly bond strength and interfacial integrity of resin composite bonded to dentin.

Four groups, each containing 10 molar teeth, were established to measure the shear strength of All-Bond 2 and Amalgambond bonded P50 resin composite assemblies at 24 hours and after 6-month water storage at 37 degrees C. An additional four groups of similarly bonded Class V restorations were subjected to the same immersion periods. Marginal leakage was determined using eosin dye and the restoration interface was observed using polyvinyl siloxane impressions to determine gap location.

The shear strength values (MPa) for All-Bond 2 were 32.68 +/- 7.12 and 23.29 +/- 5.77 at 24 hours and 6 months respectively. The mean values for Amalgambond were 26.03 +/- 5.94 and 12.90 +/- 6.90. The difference between the values at different immersion times was statistically significant (P < 0.05). There was no evidence of dye leakage in any of the teeth. No gaps were found at the margins of the restorations correlating with the absence of microleakage. Gaps were found commonly at the floor of the Amalgambond restorations.