Marginal integrity of bonded amalgam restorations

To evaluate the marginal integrity of amalgam restorations in association with four different bonding agents in an in vitro stressing system.

Cylindrical cavities were prepared in extracted human molars. The enamel-dentin interface of each cavity was treated with one of four different bonding agents and a non-bonded group. Following treatment with one of the four systems; Amalgambond (AB), Amalgambond Plus (AP) Superbond D-liner II (SD) and Bond-It (BI). Each cavity was then restored with a high-copper spherical amalgam alloy Tytin (TY). Using a load of 75 Newtons (N), a total of 100,000 cycles were applied to each restoration surface. Marginal integrity of each tooth restoration interface was replicated with epoxy and evaluated for gap width with a profilometer and SEM.

There were no significant differences in gap width between the loaded and unloaded groups. The non-bonded group (before loading) was statistically different than AB, AP, and SD. In addition, there were no significant differences among the 4-META bonded groups, regardless of the type of bond system, whether loaded or unloaded. The four different bonding agents were significantly different after loading than the non-bonded group. Our SEM and profilometry data demonstrate that the marginal integrity of amalgam alloy restorations is significantly improved by use of bonding systems.