Mechanical and corrosion behavior of some Ni-Cr and Co-Cr dental alloys

Abstract

Ni-Cr and Co-Cr alloys have been used in dentistry for porcelain-fused-to-metal (PFM) crowns due to their biocompatibility, wear resistance, long service life, good mechanical properties and superior corrosion resistance. Non-precious alloys have an improved elastic modulus compared to dental precious alloys, which allows for the use of thinner substructures in metal-ceramic restorations with a reduced amount of tissue destruction in crown preparation. The present study evaluated and compared the corrosion behavior of two NiCr-based and two CoCr-based dental materials in Ringer's solution, using the following techniques: potentiostatic polarization curves (chronoamperometry), microstructural analysis and EIS (Electrochemical Impedance Spectroscopy). The results obtained showed that for NiCr-based samples the stability of the passive layer was destroyed after polarization and stable pitting development and growth was found in the microstructural analysis after electrochemical treatment.