Shear bond strength of veneer composite to cobalt-chromium alloys fabricated differently

Objective: The purpose of this study was to assess and contrast the shear bond strength of a veneer composite resin bonded to cobalt-chromium (CoCr) dental alloys produced by different techniques. Material-Method: Ninety cylindrical specimens (10mm in diameter, 8mm in height) made of CoCr dental alloys were prepared by casting (C), milling (M), LaserCUSING with and without annealing (CL+, CL), and direct metal laser sintering (DMLS) with and without annealing (EL+, EL). Veneer composite cylinders (5mm in diameter, 3mm in height) were built on metal specimens using a silicone jig. After storage in water for 24 hours, the specimens were assessed for bond strength with a shear force test at a crosshead speed of 0.5 mm/min. The shear bond strengths (SBSs) were statistically analyzed using the Kolmogorow-Smirnow test and Tukey-HSD multiple comparison test (α=.05). Results: When the SBS values of the groups were compared, significant differences were found among the groups (P .05). The debonded surfaces of the specimens exhibited mostly mixed failure types. Conclusions: The CoCr alloy fabrication technique has an effect on the SBSs between the veneer composite resin and the metal used. LaserCUSING casting, a new technology, seems to have the lowest metal-resin bond strength among all the techniques tested.