Dental amalgam is a material composed mainly of mercury, silver, copper and tin. It has been used in dentistry for over 150 years and remains the filling of choice for less-visible teeth in the back of the mouth.

Dental amalgam has many advantages: it is inexpensive and very durable, and seals the tooth very well, thus reducing the probability of a new cavity. In addition, it can withstand pressure from chewing. The main inconvenience is its silver colour, which may not appeal to everyone.

Dental amalgams release mercury vapours, especially when we chew. Scientific studies have shown that the actual amount of metallic mercury released is well below the toxic threshold.

In fact, we all absorb other forms of organic mercury from the environment every day, from the air, water and some foods, like fish.

Health Canada does not feel that a complete ban on dental amalgam is justified, and neither is the removal of existing sound amalgam fillings. Furthermore, there is no evidence that dental amalgams are causing illness in the general population.

It is recommended that amalgams not be used for the following patients:

• People with allergies to mercury, although such allergies are rare (less than 1% of people). A skin test and an oral exam can show whether you are allergic to mercury.
• People with kidney disease.

To read Health Canada's position statement: www.hc-sc.gc.ca.

To read the statement by the Ordre des dentistes du Québec: Policies and guidelines

Advantages

• Good seal
• Durable and abrasion resistant

Disadvantages

• Not esthetically pleasing
• Allergic reactions (very rare)

The Ordre des dentistes du Québec does not recommend that patients with sound amalgams have them replaced by other types of fillings.