Selecting Metals

Selecting Metals

Every laboratory will offer different testing panels to help doctors and patients choose what to test. Typically, the panels will be based on the patient’s current exposure. Ideally, patients should contact their health care provider to find out the exact composition of their fillings, crowns, wires, pin and/or implants. The clinic/laboratory testing panels have been devised to include the most commonly found allergy causing metals in various metal alloys used in dentistry and surgery.
 
Some patients will not have any internal metal exposure but will be exposed to metals in other ways. Common sources of metal exposure include:

  • Dental restorations: fillings, crowns, pins, root-fillings, implants. Amalgam/silver fillings contain mercury, silver, tin, copper and zinc. Crowns can contain gold, silver, palladium, copper, chromium, indium, gallium, iridium, nickel and more. Implants are often made of titanium, aluminium and vanadium.
  • Orthopedic and body implants such as hip replacements, screws, nails and clips are usually made from the following:-
  • Stainless steel: nickel, chromium, manganese, molybdenum.
  • Cobalt-chromium molybdenum steel: chromium, molybdenum, nickel, iron, manganese, tungsten, aluminium, titanium, cobalt.
  • Vitallium: cobalt, chromium, manganese, molybdenum.
  • Titanium: titanium, aluminium, vanadium, nickel (trace).
  • Nitinol: titanium, nickel.
  • Oxinium: zirconium (oxidized).
  • Smoking: both active and passive smoking contain mercury, nickel, cadmium and, manganese.
  • Vaccines: may contain thimerosal (a mercury-based preservative) and aluminium.
  • Medication: antacids contain aluminium and pills may have titanium dioxide (E171) or other metal oxides in their coating to enhance their appearance. Antiseptic preparations used to contain mercury and still do in some countries. Barium is found in x-ray fluids.
  • Piercings and jewellery
  • Costume jewellery may contain a lot of different metals, most notably nickel, which often cause skin rashes in sensitive patienys. Lead may also be present.
  • In more expensive jewelry, yellow gold is made by mixing pure gold with copper and zinc; rose gold contains copper and white gold is an alloy of gold and some white metals such as silver and palladium. Other metals used in jewelry are platinum, rhodium, tungsten and titanium. Titanium is often used for piercings and there are some rare cases of allergy to titanium alloy piercings.
  • Cosmetics: titanium dioxide is widely used in cosmetics, present in many products such as eye shadow, blush, nail polish, lotion, lipstick, powder and sunscreen. Metal pigments are used to give colour and act as preservatives. The following metals may exist in cosmetic products: lead, mercury, chromium, aluminium, arsenic, beryllium, nickel, cadmium and others.
  • Foods from contaminated areas may contain more metals than others, whether fish, meat, vegetables or fruit.
  • Fish can contain high amounts of methyl mercury, which accumulates up in the food chain so that large predatory fish contain more mercury than smaller fish.
  • Seafood may contain mercury, cadmium and arsenic.
  • Nickel is found in bananas, cocoa, oatmeal, green vegetables and a variety of other foods.
  • Vegetables from polluted areas may contain cadmium, palladium, lead etc.
  • Tinned food can contain tin and aluminium.
  • Wine can contain molybdenum, nickel and lead.
  • Occupational exposure: construction workers, miners, electricians, rubber/wood/paper/textile industry workers, dentists, hairdressers and painters are some occupations that are more exposed to metals in their work than others.
  • Residential exposure: living close to a highway, airport, crematory or factory or, for example, in the same building as a dental clinic may lead to increased exposure to metals such as palladium, cadmium, lead and mercury.