What is Amlagam:

It is a mix of alloys with Mercury that, when mixed form a hard substance that has been used for ages to fill teeth.
Side effects of Amalgam:
Amalgam lasts for years and has passed the test of time, as it has been in use in dentistry for centuries. However, it may cause some allergic reactions in the gums or cheeks. The theories that Amalgam leeks mercury into the blood stream that causes illness are still to be proven. The Australian Dental Association, The National Health and Medical Research Council, and the World Health Organization do not support the views that Amalgam causes illness.

Why replace Amalgam?

we feel that we shouldn’t pressure any person to replace the Amalgams to avoid ill health. However, such concern is understandable and we are happy to do so, and we are happy to use the rubber dam while removing the Amalgam if the person chooses so. Amalgam is better replaced with a white filling when a tooth is heavily filled with it. A tooth heavily filled with Amalgam will break,

while in a case where the tooth is heavily filled with a resin-based white filling, chances are that the filling will break under pressure rather than the tooth. In any case heavily filled teeth are better restored with an extracoronal restoration, ie a crown.