Evaluation of Bond Strength of Pressed and Layered Veneering Ceramics to Nickel-Chromium Alloy

Statement of the problem: the success of metal- ceramic- restorations (mcr) depends on the presence of strong bond between porcelain and metal substructure.purpose: the purpose of this study was to evaluate the effect of hot pressing technique on the bond strength of a metal-porcelain composite in comparison to layering technique.materials and method: thirty nickel-chromium specimens were produced by two methods; conventional porcelain layering on metal and hot pressing (n=15). bond strengths of all specimens were assessed by the means of three–point bending test according to iso 9693: 1999 (e) instructions. the data were analyzed using students t-test (p < 0.001).results: the mean ± sd bond strength of conventional and hot pressing technique was 48.29 ± 6.02 and 56.52 ± 4.97, respectively. therefore, the conventional layering technique yielded significantly lower mean bond strength values than hot pressing technique (p < 0.001).conclusion: this study showed that it is possible to improve metal–porcelain bond strength significantly by applying an overpressure during porcelain firing.