Durability of resin bond strength to dental noble metal–ceramic alloys conditioned with novel mercapto silane-based primer systems

The purpose of this study was to investigate the efficacy of novel mercapto silane-based experimental primers on the resin bonding and its durability to dental noble metal–ceramic alloys in comparison with that of commercial primers. Disc-shaped gold–platinum–palladium, gold–palladium–silver, and palladium–silver alloy specimens were used as the adherents after air-abrasion. One of three commercial primers (M.L. Primer, Single Bond Universal, and All-Bond Universal) and two experimental primer systems (2-step application with γ-mercaptopropyltrimethoxysilane and then γ-methacryloxypropyltrimethoxysilane and a blend of the two silanes) was applied to each alloy. Resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and light-cured. All bonded specimens were stored in water at 37 °C for 24 h and then half of them additionally water immersed for 7 days (37 °C) and then thermocycled 10,000 times before the shear bond strength test (n = 10). The surface energy parameters for unprimed a...