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the Australian Dental Association
Written by the Australian Dental Association, Jun 16, 2022
Fact Checked

Fillings are used to replace natural tooth structure when it becomes fractured, broken or damaged by tooth decay. If you need a filling, your dentist can use a range of filling materials to fix your tooth. A filling will fix the tooth so it looks and works at its best. 

Filling material options

When a filling is needed there are different filling material options that your dentist can choose from to fix the tooth. Each filling material has advantages and disadvantages. There are different factors that can influence the choice of filling material. Some factors include where the tooth is located in the mouth, how the teeth bite together and the how big or small the filling will be. Your dentist will give you advice on what is best for your tooth. This could be different for each tooth. 

Amalgam

Dental amalgam is a silver-coloured filling material. It is made of mercury, silver, copper, zinc and tin. It has been used as a filling material to fix teeth for over 150 years and has one of the longest life-expectancies of dental filling materials. Dentists and scientists have done a lot of research on dental amalgam. 

Amalgam was commonly used by dentists in the 1990’s. These days it is used less commonly. Some dental practices do not use it at all any more. Amalgam is strong and long-lasting, but more tooth structure needs to be cut away to fix the tooth with an amalgam filling. This is because the amalgam is held in place by the shape of the cavity that is cut into the tooth. Amalgam does not stick to the tooth surface like white filling materials do.

This filling material is silver in colour and can appear darker over time. Some people claim that mercury in dental amalgam can cause health issues. There is no quality research that has shown that this is true. Scientific research has shown that the mercury in amalgam fillings is not absorbed well by the body. Small amounts of mercury from amalgam do get into the blood but are removed by the kidneys and passed out of the body in urine. There are only two proven side-effects of amalgam:

  • Lichen planus - a condition involving small sores on the gum or inside of the cheek.
  • An allergic reaction affecting the soft tissues near the filling. Signs of an allergic reaction can include swelling, redness, and itching, but these are rare.

Dental amalgam has been used less and less in dental clinics over the years. The decreased use of amalgam is not due to concerns directly related to human health but concerns about the environment. Mercury from dental clinics can get into the environment. To stop this, dentists have created policies and installed equipment to help them to safely get rid of amalgam waste to limit the amount released into the environment.

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A dental amalgam filling in a molar tooth. Getty Images.

Should I remove my amalgam fillings?

Dental amalgam is a safe and very useful filling material. There is no need to remove and replace your amalgam fillings for no specific reason. There is no evidence that changing healthy amalgam fillings with a different material option, without a specific reason, will produce a better health outcome for patients.

If you choose to have your amalgam fillings removed, make sure you understand the effects of this decision. Each time a filling is cut out of a tooth, more tooth strucuture is cut away. There is also no guarantee that the new filling or material will be better than the amalgam filling already in place. All dentists are trained in how to remove and replace amalgam fillings. Dentists do not need specifialist training to do this.

Even though dental amalgam is not commonly used any more, your dentist may still recommend it as the filling material of choice for certain situations.

Composite resin

Composite resin is a tooth-coloured or white filling material. It can be used for fillings in both the front and back teeth. It is commonly used to fix broken or decayed teeth and for cosmetic dental treatments, such as veneers. Composite resin fillings are glued to the surface of the tooth, which is called bonding. Because composite resin is bonded to the tooth’s surface, less tooth structure needs to be cut away for the filling to be placed. This means more natural tooth structure can be kept.

The colour of the material can be matched to the tooth being fixed. When the colour is well matched, the filling may not be able to be found by other people looking at your teeth. 

Before and after a composite resin filling in a molar tooth. Getty Images.

Left Cavity cut into the tooth after removing tooth decay. 
Right Cavity filled with a tooth-coloured composite resin filling.
This filling was completed using a rubber dam to isolate the tooth from the rest of the mouth.

Glass-ionomer cement

Glass-ionomer cement (GIC) is also a white or tooth-coloured filling material. It is not as strong as composite resin. Fluoride is an ingredient in this filling material. It has many uses but common uses include fissure sealants and temporary fillings.

Gold and porcelain

Fillings can be made of gold and porcelain. These fillings are created outside of the mouth and then glued into the tooth’s cavity. This type of filling is called an inlay.

Gold and porcelain inlays are very strong and can last a long time. The porcelain inlay can also be matched to the colour of your tooth. Both gold and porcelain inlays take time as they need to be made at a dental laboratory. It often takes at least two appointments.

A gold inlay used to fix a molar tooth. Getty Images.

Fissure sealants

Fissures are the grooves that are naturally present on the top, biting surface of the back teeth. These grooves can be very thin and deep. This can cause food and bacteria to become stuck. When food and bacteria keeps gets stuck over and over again, it can increase the risk of tooth decay developing inside the grooves.

A fissure sealant is a thin layer of filling material placed over the grooves of the teeth. It is done to prevent food and bacteria sticking in the grooves and to decrease the risk of tooth decay developing. Fissure sealants are most commonly placed in the grooves of the back adult molar teeth in children and teenagers. Sometimes other teeth may also need fissure sealant treatment. The filling material is commonly white or clear. Sometimes the filling material will include fluoride for even more protection. Over time, using your teeth can cause the fissure sealant to wear down.

Fissure sealant in a back molar teeth. Getty Images.


Fissure sealants are not required in all children. Your dentist will let you know if this treatment is recommended for your childrens teeth.

Temporary fillings

Your dentist may call a filling they are placing in your tooth as temporary. In certain situations, a temporary filling may be placed in a tooth. An example of when a temporary filling may be used is when the filling material will need to be removed again very soon or at your next dental appointment. Example situations where this may be done can include:

  • when the same tooth needs to be treated a few times over multiple appointments,
  • there is not enought time to complete a treatment in one dental visit,
  • during emergency dental treatment, or
  • when covering up a tooth cavity between root canal treatment appointments.

After a filling

After a filling, the treated tooth may be sensitive when biting down or to hot and/or cold temperatures. This is called post-operative sensitivity. The sensitivity should go away after a few days. Sometimes, it can last 1 or 2 weeks. If the sensitivity does not go away or becomes worse where it causes pain, you should return to your dentist for them to investigate further.

How long will my filling last?

Fillings do not last forever. Fillings can become worn, chipped, cracked, or they may change colour. Over time, pressure applied to teeth can cause the join between the tooth and the filling to open. This can let food particles and decay-causing bacteria to collect in this space. This may cause tooth decay. The amount of time a fillings lasts for can also depend on how well you look after it. It is important to brush your teeth twice daily and clean between your teeth every day as well. 

Fillings can change colour. This means they may no longer match the colour of your natural tooth. This may be a concern for some people when it affects the front teeth. A dentist can replace the filling so it matches the colour of your natural tooth again.

Summary

Your dentist has many filling material options available to them. They will let you know the best filling material to fix your tooth. Make sure to continue seeing your dentist for regular check-ups so that they can monitor your fillings. Your dentist can detect and treat any issues before they become more serious. If you are due for a check-up but do not have a regular dentist use the ADA's Find-A-Dentist search tool to find a ADA member dentist near you.