The picture above is a cross-section of gold foil alloy porcelain teeth, and the metal layer of nichrome alloy porcelain teeth is white. Nickel-chromium alloy porcelain teeth are corrosion-resistant and inexpensive, and are currently the most commonly made porcelain teeth in China. Medical nickel-cadmium alloy, mainly composed of nickel, chromium and other small amounts of harmless metal elements, nickel-chromium alloy on the human body is mainly caused by the adverse effects of nickel. (1) Modern medicine proves that nickel is allergenic and carcinogenic to the human body, which can cause slight inflammation of gums in some people, resulting in slight redness and swelling of porcelain teeth in contact with the gums, which is harmful to the health of the gums and affects the beauty. (2) nickel chemical instability, its metal ions precipitation, oral odor, metal ions deposited in the cervical edge of the gums, so that the gums become black, porcelain teeth neck edge black, affecting the aesthetics. Some bad dental clinics or processing plants to reduce costs using industrial nickel-chromium alloy instead of medical nickel-chromium alloy, industrial nickel-cadmium alloy contains beryllium and other harmful impurities, beryllium has a carcinogenic effect on the human body, is strictly prohibited for human use. Foreign data show that 15-20% of women and 1-2% of men who wear nickel-containing hand jewelry have allergies and inflammatory reactions in the skin and mucous membranes. The probability statistics of allergy occurring in the oral cavity are rarely reported, but should not be as high as the probability of skin allergy, but once the allergy brings both pain to the patient and great trouble to the physician. Nickel-chromium alloy is also shown in the color gray and black, although the alloy surface covered by porcelain and does not show, but in the neck porcelain and metal joints can have black lines appear, especially after a long time is more obvious. In addition, recent studies have shown that nickel-containing dust, aerosol and long-term human contact can cause conjunctivitis, bronchitis, skin inflammation, and even become nasopharyngeal cancer, lung cancer carcinogenic factors. Some European countries, the authorities warned not to use nickel content of more than 1% of the alloy, and porcelain with nickel content is generally between 62 ~ 82%, so the nickel-chromium alloy porcelain teeth in these countries has actually lost the market. Studies have shown that the amount of chromium in the alloy has an absolute influence on the corrosion resistance of Ni-Cr alloys in the oral cavity. When the content of chromium in NiCr alloy exceeds 20%, the alloy is relatively stable and has a high corrosion resistance. On the contrary, the alloy is highly susceptible to corrosion and nickel ions are continuously precipitated, which will cause gum discoloration and blackening after absorption by human body. Some poor nickel-chromium alloy contains harmful elements of beryllium (carcinogenic metal), even if the content is very low, it can also cause great harm to health. Therefore, if the economic conditions permit, try to choose precious metal porcelain teeth, or all-porcelain crown porcelain teeth. More links 1. How to choose porcelain teeth, materials, prices http://blog.sina.com.cn/s/blog_65ccf1b10100zdx1.html 2. What is all-ceramic teeth, classification, prices, advantages and disadvantages http://blog.sina.com.cn/s/blog_ 65ccf1b10100yp9f.html 3. What is precious metal porcelain teeth, price, advantages and disadvantages http://blog.sina.com.cn/s/blog_65ccf1b10100ya9p.html 4. What is cobalt chrome porcelain teeth, price, advantages and disadvantages http://blog.sina.com .cn/s/blog_65ccf1b10100ya99.html 5. What is nickel-chromium porcelain teeth, price, hazards http://blog.sina.com.cn/s/blog_65ccf1b10100xxm9.html 6. What is dental implant http://blog.sina.com .cn/s/blog_65ccf1b10100hxgu.html 7. How to brush your teeth, and how to floss === video teaching http://blog.sina.com.cn/s/blog_65ccf1b10100hjk0.html 8. Porcelain veneer cosmetic repair side cut over small teeth Tanggu Wu Shichao http:// blog.sina.com.cn/s/blog_65ccf1b10100nns1.html 9. Zirconium dioxide is not a panacea, need whitening assistance http://blog.sina.com.cn/s/blog_65ccf1b10100nypo.html 10. Precision attachment Repair free missing http://blog.sina.com.cn/s/blog_65ccf1b10100iova.html 11. Make “sleeve crown” laugh —– happy dentist Wu Shichao http://blog.sina.com.cn/s/ blog_65ccf1b10100ovhs.html price The price of nickel-chromium alloy porcelain teeth in Tianjin Tanggu Dental Hospital is 400 yuan per piece, the price varies from region to region between 300-800 per piece