Evaluation of the effect of recasting on the elastic modulus of Ni-Cr dental alloy structures: An in vitro study

Aim: To evaluate the effect of recasting on the elastic modulus of Ni-Cr dental alloy structures. Materials and Methods: This study was of an in vitro experimental type. The sample consisted of n=30 specimens that were divided into three groups. The study was conducted in vitro, both prospectively and longitudinally, on rectangular specimens of Ni-Cr dental alloy structures made with specific measurements by means of a casting process using the lost wax technique. Subsequently, a laboratory test to obtain the value of the elastic modulus was conducted by means of a bending test with a universal testing. The groups were as follows: Group 1: 100% reused Ni-Cr dental alloy structures; Group 2: 50% reused Ni-Cr dental alloy structures; and Group 3: 25% reused Ni-Cr dental alloy structures. The data were expressed in mega pascals (MPa). All statistical analysis was performed by using Stata software with a confidence level of 95% (Kruskal-Wallis test was used (p 0.05)). Results: When evaluating the elastic modulus of group 1 (100% reused Ni-Cr dental alloy structures), it was found that the highest value was in the first recast. In both group 2 (50% reused Ni-Cr dental alloy structures) and group 3 (25% reused Ni-Cr dental alloy structures), the highest values occurred in the third recast. Conclusions: The number of recasts did not influence the modulus of elasticity of the Ni-Cr dental alloy structures tested in this study.