Although numerous types of porcelain-fused-to-metal crowns are available, many patients opt for nickel-chromium alloy crowns due to economic constraints. This remains China's most widely used porcelain crown primarily because of its low cost. What are the risks associated with this type of crown?
Nickel-chromium alloy offers corrosion resistance and affordability, making it the most commonly produced porcelain crown domestically.Medical-grade nickel-cadmium alloys primarily consist of nickel, chromium, and trace amounts of other metals harmless to humans. Nickel-chromium alloys have adverse effects on the human body, primarily due to the nickel content.
Nickel-chromium alloy porcelain-fused-to-metal crowns are currently the most widely used type in China due to their low cost. In domestic alloys, nickel accounts for approximately 70%, chromium for about 30%, with the remaining 3% comprising metals like ruthenium, tin, and manganese.
Hazards of Nickel-Chromium Alloy Porcelain-Fused-to-Metal Crowns:
1. Modern medical research confirms nickel's allergenic and carcinogenic properties. It may cause mild gum inflammation in some individuals, leading to slight redness and swelling where the crown meets the gumline. This compromises gum health and affects aesthetics.
2. Nickel's unstable chemical properties cause metal ions to leach out, producing an unpleasant metallic taste in the mouth. These ions deposit along the gumline, darkening the gums and causing discoloration at the crown's base, compromising aesthetics.Some unscrupulous dental clinics or laboratories substitute industrial nickel-chromium alloys for medical-grade ones to cut costs. Industrial nickel-cadmium alloys contain harmful impurities like beryllium, which is carcinogenic to humans and strictly prohibited for medical use.
Over 50% of patients opting for porcelain-fused-to-metal crowns choose this type. Clinical observations indicate that some individuals exhibit nickel allergies, leading to inflammation of the skin and mucous membranes.