Effect of an acidulated fluoride etchant on bonding between titanium and two luting materials

Adhesive bonding between resin and titanium is useful for resin-bonded prostheses. The purpose of this study was to investigate the efficacy of an etchant, consisting of ammonium hydrogen fluoride (AHF) and phosphoric acid (PA), in titanium bonding. Cast specimens of commercially pure titanium were air-abraded with alumina and etched for 30 s, after which a primer (ALP) was applied. An acrylic rod was bonded to the specimen with one of the two luting agents being examined (Super-Bond QUICK and Panavia F2.0). Shear bond strengths were determined following 10,000 thermocycles. When Panavia F2.0 was applied, neither the etchant nor the ALP primer showed significant effect on bond strength. The postthermocycling bond strength of Super-Bond QUICK was significantly improved with the use of an etchant and ALP primer. Although microscopic observation revealed that considerable numbers of submicron pits were created on the specimens etched using AHF with PA, no significant difference in bond strength was detected in the application of AHF, with or without PA. The present findings suggested that the improved bonding durability was due to the micromechanical retention between the resin and the microscopically roughened titanium surface.