Behavior of Two Dental Alloys as Ingot and Cast Crown in Artificial Saliva

Abstract

Dental alloys based on Co or Ni are commonly used in dentistry to fabricate dental prostheses, including crowns, bridges, and partial dentures, but even though both alloys are highly biocompatible, some patients may experience allergic reactions to nickel. This comparative study investigated the behavior of two dental alloys in the oral cavity, analyzing their microstructure, corrosion behavior, elastic modulus, hardness, and tensile strength for ingot and cast crowns. The microstructures of commercial Ni-Cr and Co-Cr samples were analyzed using optical microscopy, scanning electron microscopy (SEM), and X-Ray Diffraction (XRD); elastic modulus and corrosion behavior were determined after immersing the samples in artificial saliva. Ni-Cr alloy has a corrosion potential more negative than Co-Cr alloy; this means that the first alloy is more likely to undergo corrosion than the second alloy. Ni-Cr sample with a higher elastic modulus is generally more rigid and less flexible than Co-Cr sample with a lower elastic modulus. The analyzed Co-Cr alloy has a higher resistance to corrosion, resulting in a more esthetically pleasing and longer-lasting restoration. The Co-Cr alloy also has a lower density than the Ni-Cr alloy, which, combined with its strength-to-weight ratio, makes them ideal for partial dentures where the prosthesis needs to be lightweight. The Co-Cr alloy is more flexible than the Ni-Cr alloy, making it stronger and more durable. This makes them an ideal choice for dental prostheses that need to withstand high stresses and loads.