Effect of surface treatment on resin bonding to 3D printed Co-Cr dental alloy

Objectives. Despite the widespread use of resin cements in bonding different dental restorations, their bond strength to 3D printed Cobalt-Chromium alloys has not been thoroughly studied.
Abstract: The study compared three different surface treatment methods on the shear bonding of adhesive resin cement to laser sintered Co-Cr alloy. The surface treatment methods were blasting with 30µm alumina chemically modified with silica (Cojet sand) for group A, fine 50µm and 110µm aluminum oxide blasting for groups B and C respectively.
Materials and Methods: Thirty disk-shaped samples of 8mm diameter and 3mm thickness were manufactured of 3D printed (laser sintered )Co-Cr alloy, then were wet ground with 200-1000-grit silicon carbide abrasive then polished. Disks were divided to three groups according to the selected surface treatment method. Self adhesive resin cement disks of 5mm diameter were bonded to the alloy samples with the aid of a Teflon mold following manufacturer’s instructions. Bonded samples were thermocycled (2000 cycles between 5°and 55°C, 30 seconds dwell time) to simulate fluctuation of temperature within the oral cavity. Then, shear bond test was performed and mode of failure was inspected.
Results: debonding numericals were analyzed using one-way ANOVA followed by Tukey’s post hoc test. The significance level was set at p<0.05 within all tests. Shear bond values were greater when sandblasting with aluminum oxide was used((12.35±1.53 and 11.85±1.41)MPa, compared with silica blasting (6.84±1.14) MPa. A combined failure mode (adhesive-cohesive)was encountered at the resin cement –alloy interface.