Amalgam Fillings

Dental amalgam is a dental filling material used to fill cavities caused by tooth decay. It has been used for more than 150 years in hundreds of millions of patients around the world. Dental amalgam is a mixture of metals, consisting of liquid mercury and a powdered alloy composed of silver, tin, and copper. Approximately 50% of dental amalgam is elemental mercury by weight. The chemical properties of elemental mercury allow it to react with and bind together the silver/copper/tin alloy particles to form an amalgam. Amalgam is very hard-wearing so it is ideal for fillings in your back teeth. Amalgam fillings can last for 20 to 40 years, as long as you take good care of your teeth.

During the appointment

When placing dental amalgam, the dentist first drills the tooth to remove the decay and then shapes the tooth cavity for placement of the amalgam filling. Next, under appropriate safety conditions, the dentist mixes the powdered alloy with the liquid mercury to form an amalgam putty. This softened amalgam putty is placed and shaped in the prepared cavity, where it rapidly hardens into a solid filling. Once the material is set, the dentist will check your bite and adjust accordingly.

After having a filling

The local anaesthetic will make your gums, tongue, cheeks and even your lips feel numb for a while. Until this wears off, you may have difficulty talking, chewing and drinking. As sensation returns, you may feel some tingling. Avoid chewing on that side for a while, partly to protect your filling but also to prevent accidentally biting yourself.

For up to a week after your filling, your tooth may be more sensitive to cold and heat. If it gets much worse or goes on for longer, tell your dentist – this could indicate changes to the nerve, which may need treatment. If the tooth cavity is very deep, or the centre of your tooth is damaged, you may need root canal treatment to avoid having the tooth out. Although often called ‘root canal fillings’, these aren’t the same as a standard filling.

Things you should know before deciding on amalgam fillings

Deciding what filling material to use to treat dental decay is a choice that must be made by you and your dentist.

There are some cases where it would be best to talk with your dentist about alternatives to traditional amalgam. If you have a known allergy to mercury, are exposed to high levels of mercury daily, or are pregnant, make your dentist aware before having any dental work done.

If you would like to avoid amalgam altogether, there are alternative materials like composite resin. Composite resin can be more visually appealing because it is a tooth-coloured material. However, it takes longer to set and wears faster than amalgam, which means it can’t be used in every situation.

Is Amalgam Safe?

Some concern has been raised in the past over the elemental mercury used in amalgam (which we will get into soon), but there’s no need to worry. As of 2017, the FDA says that amalgam fillings are safe for adults and children six years old and older. Millions of people have amalgam fillings, and after extensive research and review of amalgam studies, the FDA has not found any reason to limit its use.