A strong durable resin bond to fresh amalgam is desired in composite-v
eneered amalgam restorations and in adhesive amalgam restorations. The
purpose of this study was to evaluate the influence of long-term wate
r storage on the durability of the shear bond strength of new adhesive
systems bonded to fresh amalgam. Sixty cylindrical specimens composed
of equal parts of amalgam and composite, with a layer of bonding mate
rial in between, were prepared for each adhesive system: All-Bond 2, A
malgambond Plus, High-Q-Bond, and Comspan. Specimens were divided into
three subgroups and immersed in saline at 37 degrees C for either 48
hours, 3 months, or 6 months. After the immersion period, specimens we
re thermocycled and subjected to shear bond strength testing. Shear bo
nd strength of Comspan and High-Q-Bond adhesives did not deteriorate s
ignificantly during the B-month experiment and maintained a mostly mix
ed mode of failure. All-Bond 2 and Amalgambond Plus adhesives exhibite
d deterioration of the shear bond strength as a function of immersion
time and shifted from dominantly mixed mode of failure to totally adhe
sive (All-Bond 2) or mostly adhesive failure (Amalgambond Plus). Incub
ation in saline for long periods should be a standard test in evaluati
ng the bond of new adhesive systems to fresh amalgam, whereas short ex
posure time to water might be misleading.