Shear bond strengths of 10 adhesive resin/amalgam combinations

This study compared the shear bond strengths of amalgam to dentin using two amalgam alloys and five adhesive resin systems. One hundred extracted human third molars were flattened occlusally to expose dentin. Dentin surfaces were treated with one of five adhesive resins: All-Bond 2, Amalgambond Plus, Amalgambond Plus with HPA Powder, OptiBond, and Resinomer. Tytin (spherical) or Dispersalloy (admixed) amalgam was condensed onto the treated dentin surface through a Teflon split mold. The samples were stored 7-10 days and thermocycled before shear testing using a Zwick Materials Testing Machine. Two-way ANOVA revealed significant differences among the 10 groups (P < 0.05). The combination of Tytin/OptiBond produced the highest bond strength to dentin (14.17 MPa), while Dispersalloy/Amalgambond Plus produced the lowest (3.89 MPa). In general, the filled resin systems (Amalgambond Plus with HPA Powder, OptiBond, Resinomer) produced higher bond strengths than the unfilled systems (All-Bond 2, Amalgambond Plus). Additionally, for four of the five resins, bond strengths were higher with Tytin than with Dispersalloy, although differences were statistically significant in only two groups.