The Amalgam Dilemma

The debate over the safety of amalgam fillings has been going on for decades and has caused much confusion and anxiety among consumers. The presence of mercury in amalgam has often been blamed for ill-health by some misinformed groups or parties with personal interest in this matter, in particular manufacturers of tooth-coloured dental materials. Dr Andrew Chan Kieng Hock discusses objectively the toxic effects of mercury as an element and presents a holistic view on the safety aspect of amalgam in dentistry.

- Dr Andrew Chan Kieng Hock

WHAT IS MERCURY?

Mercury is a naturally existing element in the environment. It is highly lipid-soluble and easily infiltrates nerve cells in our body. In high quantity, mercury can cause neurotoxicity (damage to the brain and nerves) and nephrotoxicity (damage to the kidneys). The World Health Organization (WHO) recommends that mercury is safe when the intake is less than 0.47 micrograms (µg) per kilogram body weight in a day.

There are three primary types of mercury:

Elemental mercury, which is found in the air as vapor and dental amalgam

Inorganic mercury compounds, for example, mercuric chloride, mercuric acetate, and mercury sulfide

Organic mercury compounds such as methylmercury.

Methylmercury is the most toxic mercury element and is found mostly in big fishes such as tuna, shark, and swordfish. It is mainly absorbed through our gut when we eat those types of fish. Most of the mercury that we ingest is through our food.

Each person’s body processes these different forms of mercury differently with different levels of tolerance. Exposure to mercury can be an occupational hazard for people working with the element eg, factory workers in the manufacture of thermometers as well as dental health providers. However, with good work practice in handling and proper disposal, mercury poses a negligible health hazard to people.