Silver fillings were once the most common type of filling material used in dentistry. Silver fillings are also referred to as amalgam fillings. Since the introduction of the tooth-coloured filling materials, the use of amalgams has dramatically decreased. Many people still have silver fillings and have questions about their safety.
Silver fillings contain a mixture of metals (alloy), including silver, mercury, tin, and copper. The alloy is in powder form and is mixed with about 50% liquid mercury by weight. These combine to form the amalgam which is placed into the prepared tooth. The filling gradually hardens into a strong dental filling.
Amalgam fillings are very durable and affordable. They have a long life-span and can withstand a lot of force. When correctly placed, they last many years.
The mercury content of amalgam fillings has led to the controversy and questioning of their safety. Mercury is a naturally-occurring element that is toxic in large quantities. Amalgam fillings release low levels of mercury in vapor form. However, studies show that the amounts released are not harmful. Health Canada has approved dental amalgams for use. Furthermore, there is no scientific evidence to indicate harm to the general public.
They should not be used during pregnancy, or for children under 6 years of age. Those with impaired kidney function should not have amalgam fillings placed. Same for those with sensitivities to the components of amalgams.
Aesthetics- Patients don’t like the dark color of the amalgam fillings. They prefer natural looking tooth-coloured fillings, especially for front teeth.
Conservative preparations- Tooth-coloured fillings bond directly to the tooth. Amalgam fillings require more of the tooth structure to be removed when preparing the tooth for a filling.
Expansion/contraction- When having hot or cold foods, the metals in amalgams expand and contract. This occurs at a different rate than natural teeth. As a result, it creates pressure against teeth which leads to micro-fractures in the enamel. Tooth sensitivity is another side effect of micro-fractures.
Break down- While amalgam fillings last a long time, they eventually break down. A dark halo or shadow surrounding the filling may mean it is time for a replacement.
Tooth sensitivity- This can be due to micro-fractures, corrosion or the conduction of hot and cold by the metal filling. Increased sensitivity in a tooth with an amalgam filling, may require replacement.
Decay- Decay under or around an amalgam filling also requires replacement.
If your silver fillings are intact, it is usually not recommended to replace them. Mercury exposure is highest during the placement and the removal of amalgam fillings. Removing them unnecessarily is not recommended.
If you have any further questions or concerns about your amalgam fillings, call us today!