Nickel-Chromium Alloys

Nickel-chromium (Ni-Cr) alloys are base metal alloys commonly used in dental prosthetics, containing approximately 60-80% nickel, 11-20% chromium, and smaller amounts of molybdenum, beryllium, and other elements. They offer high strength, hardness, and resistance to deformation, making them suitable for PFM crown frameworks and fixed prosthetic substructures. The primary advantage of Ni-Cr alloys is their low cost compared to noble and high noble alloys, combined with adequate mechanical properties for most clinical applications. Their high modulus of elasticity allows thinner framework designs, conserving space for the porcelain veneer layer. The chromium content provides corrosion resistance through surface oxide formation. However, nickel is the most common cause of metal allergy in the general population, with estimated prevalence of 10-20% in women and 1-3% in men. Allergic reactions can manifest as contact dermatitis, stomatitis, or in severe cases, systemic symptoms. Some Ni-Cr alloys contain beryllium, which poses inhalation health risks during laboratory processing. Due to these concerns, many dental professionals prefer nickel-free alternatives such as cobalt-chromium alloys.