A comparative evaluation of bond strength of feldspathic porcelain to nickel-chromium alloy, when subjected to various surface treatments: An in vitro study

PURPOSE OF THE STUDY: The purpose was to evaluate the effect of various surface treatments and sandblasting with different particle size on the bond strength of feldspathic porcelain with predominantly base metal alloys, using a universal testing machine. MATERIALS AND METHODS: Totally, 40 specimen of nickel-chromium alloy were prepared in an induction casting machine. The groups divided were as follows: Group I-sandblasted with 50 μ Al(2)O(3), Group II-sandblasted with 110 μ Al(2)O(3), Group III-sandblasted with 250 μ Al(2)O(3) and Group IV-sandblasted with 250 μ Al(2)O(3,) followed by oxidation and again sandblasted with 250 μ Al(2)O(3). The dimensions of each specimen were adjusted so as to maintain the thickness of ceramic at 1 mm. The specimen were loaded on the assembly of the universal testing machine, and a cross head speed of 0.5 mm/min was used to apply a compressive force at the junction of metal and feldspathic porcelain. The force application continued until adhesive fracture occurred, and the readings of the load applied to that particular specimen were recorded. RESULTS: The means for shear bond strength for Group I, II, III and IV were found to be (226.92 ± 1.67), (233.16 ± 3.85), (337.81 ± 16.97) and (237.08 ± 4.33), respectively. Means of shear bond strength among the groups were compared using one-way analysis of variance test. Comparison between individual groups were made with Tukey's Honestly Significant Difference post-hoc test. CONCLUSION: Different particle size and surface treatment have an important role on the bond strength of ceramic-metal interface. Greater particle size demonstrated higher bond strength.