A comparison of the shear bond strengths to a resin composite of two conventional and two resin-modified glass polyalkenoate (ionomer) cements.

The inability of resin composite to bond directly to dentine has compromised the clinical success of this restorative material. This problem may be overcome by the so-called laminate technique in which glass polyalkenoate cement is placed upon dentine and then covered with a resin composite. The cement both adheres to dentine and affords micromechanical attachment to the composite. The introduction of the resin-modified glass polyalkenoate cements (RMCs) offers the potential for chemical union between cement and composite. This investigation examined the shear bond strengths of P-50 resin composite to four glass polyalkenoate lining materials, with and without the application of an intermediate bonding agent (Scotchbond 2). Two of the cements were RMCs (Vitrebond, XR-Ionomer) and the others were conventional base materials (Baseline, Ketac-Bond). The bond between P-50 and Vitrebond with or without Scotchbond 2 was significantly (P < 0.01) stronger and more consistent (P < 0.05) than that observed for all other materials. The treatment of the conventional materials and XR-Ionomer with Scotchbond 2 significantly (P < 0.01) improved the bond strengths to P-50. It is concluded that Vitrebond formed the most favourable cement-resin composite bond and that the other materials studied should be used in conjunction with an effective intermediate bonding agent, such as Scotchbond 2.