Tensile strength of three resin cements following two alloy surface treatments.

Retainers for composite retained prostheses ("Maryland bridges") have traditionally relied upon an etched base metal alloy for micromechanical retention. This study compared the tensile bond strength of three resin cements using two alloy surface treatments. Rexillium III and Olympia disks were cast, oxidized, and given simulated porcelain firings. Paired specimens were cemented with Comspan, Panavia EX, or C & B Metabond after air abrasion with aluminum oxide or silicoating. Air-abraded Olympia disks were tin plated prior to luting with Panavia EX. Electrolytically etched Rexillium III specimens luted with Comspan served as controls. Specimens were thermocycled and tested in tension. Highest tensile bond strengths were achieved with: (1) Olympia specimens, where the bonding surface was air abraded but tin plated before cementation with Panavia EX, and (2) Rexillium III specimens, where the bonding surface was air abraded or silicoated and the disks were cemented with C & B Metabond.