Dental Fillings

Last updated: 25th July 2023

Written by: Dr Zaeem Jafri


What is a Dental Filling?

A dental filling is a procedure used to restore the function, integrity, and shape of a tooth that has been damaged due to decay or trauma. A filling prevents further damage and infections by sealing the hole or cracks, ensuring the tooth can function normally.

When is a Filling Needed?

A filling is typically required when:

  • A tooth has decay that has caused a cavity.

  • There's a chip or crack in the tooth.

  • Old fillings break down or fall out.

  • The side of a tooth gets worn down due to habits like nail-biting or tooth-grinding.

Different Types of Fillings

Dental fillings are made up of different materials. The most common types of fillings are:

Amalgam (Silver) Fillings

Durable and cost-effective metal amalgam fillings have been used for decades. They are noticeable due to their silver colour but are highly resilient. Modern dental clinics are phasing out the use of amalgam more and more because of environmental mercury concerns and the fact that patients don’t like big pieces of metal in their teeth.

Amalgam fillings don’t stick to your teeth but are held in mechanically by the shape of the cavity.

Composite (Tooth-Colored or white) Fillings

Made from a mixture of resin and glass filler particles, these fillings can be matched to your tooth colour, making them aesthetically pleasing. Composite fillings bond directly to your tooth and can be stuck into your teeth without drilling a retentive cavity.

Ceramic Fillings (inlays and onlays)

Made from porcelain, these fillings are incredibly strong and can be made to look extremely natural. Porcelain inlays and onlays are made by a lab technician and cemented in place by your dentist. These are done when there is significant tooth structure loss or the cavity is extremely deep.

These fillings are known as ‘indirect’ fillings.

Gold Fillings (inlays and onlays)

Made from gold, they are well-tolerated by gum tissues ad your teeth. Gold fillings are highly effective and can last a very long time. However, due to how expensive they are, the improvements in porcelain and composite materials and their appearance, they are harder to come by.

Glass Ionomer (GIC) fillings

Made of acrylic and a specific type of glass material, these fillings release fluoride, which can help protect the tooth from further decay. GIC fillings are often used when dentists need to place a long-term temporary filling. GIC fillings are not used as permanent fillings.

Temporary fillings

There are several different materials used for temporary fillings. These are done in emergency situation when a dentist may not have the time to carry out a final filling or when a dentist thinks that they will need to re-access a cavity at a subsequent appointment.

The Process of a Dental Filling

A filling is now one of the most common procedures in dental surgery; below is an overview of how fillings are placed.

  1. Diagnosis: Using X-rays alongside a clinical examination, your dentist will identify the area of decay an analyse what the most effective way to treat the tooth will be

  2. Local Anesthesia: Before the filling procedure, your dentist will use some local anaesthetic the make the tooth go numb so that you don’t feel any pain during the procedure.

  3. Isolation: In order for a tooth-coloured composite filling to stick to your teeth, your tooth needs to be kept completely dry. Your dentist will isolate your tooth using cotton wool rolls, dry tips and rubber dams.

  4. Removal of Decay: The dentist will remove the decayed tooth portion using specialised tools, including handpieces and burs (what most people call the drill).

  5. Cleaning the Cavity: After removal, the cavity is thoroughly cleaned to prepare for filling. For composite fillings, the cavity will be conditioned and a ‘bond’ (glue) will be placed to allow the filling to stick to your tooth.

  6. Filling: The chosen filling material will be placed in the cavity and shaped to match the contour of the tooth.

  7. Polishing: Finally, the dentist will polish the filled tooth, ensuring it feels smooth and natural.

The final finished filling should feel natural, without sharp or rough surfaces. You should be able to bite comfortably on the tooth; if not, your dentist can mark any high spots on the filling and adjust them to the correct height.

How to Look After a Filling

Looking after your filling is extremely important. Bacteria can infiltrate your tooth and cause more decay underneath the filling, so you need to ensure you keep the edges of your filling clean and free from plaque buildup.

  • Regular Oral Care: Brushing twice daily and flossing daily will keep the filled tooth clean. Fillings commonly occur between teeth, so flossing the margins of the fillings is extremely important.

  • Avoid Hard Foods: Especially after a new filling, it's advisable to steer clear of very hard or crunchy foods that could dislodge the filling.

  • Regular Dental Checkups: Ensure you have regular check-ups to monitor the filling status and catch any potential issues early. For example, if a gap between the filling nad tooth and decay starts to spread again, you want to catch this early on an x-ray.

  • Avoid Grinding: If you have a habit of grinding your teeth, consider a night guard to protect your filling and other teeth.

How to brush your teeth properly

How Long Do Fillings Last?

The lifespan of a dental filling largely depends on its type and where it's placed, so it is hard to say precisely how long a filling will last. Generally, if a filling is placed correctly in good condition, it should last 12-15 years; however, this depends on several factors.

  • You must ensure you are cleaning and looking after your filling correctly.

  • The dentist needs to be able to access the tooth and keep it dry; this can be difficult in hard-to-reach areas of your mouth.

  • Some fillings can be extremely deep, and moisture from your gums can affect the seal of the filling; your dentist will let you know if there is a risk of this affecting your filling.

  • Some fillings can be very deep and close to your nerve, and even if the filling is okay, the nerve underneath the filling may die. In this scenario, you may need a root canal filling or extraction instead.

Regular dental visits will help ensure your fillings are in good shape and doing their job of protecting your teeth.

Fillings on the NHS

NHS dentists will offer silver amalgam fillings for your back teeth and tooth-coloured composite fillings for your front teeth. Fillings on the NHS currently cost £79.70, although you should check this website as the prices change every year. £79.70 is the total fee you will pay for your check-up and fillings (no matter how many fillings you need).

Speak to us about fillings

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Common questions about fillings

When can I eat/drink after a filling?

There are a few things to consider here. Firstly, if your dentist used local anaesthetic you need to wait until you regain feeling in your mouth again. Eating when your mouth is numb can be dangerous (you may end up damaging and chewing your lips and cheeks without realising)

Amalgam fillings set to their full strength over the next day so wait for the next day before you start eating on that tooth.

Composite fillings set to their full strength immediately.

Are fillings covered by dental insurance?

Yes, fillings are almost always covered by dental insurance companies, however, there may be limitations to the amount of cover they provide.

Are amalgam fillings safe?

Many people are worried about the fact that metal amalgam fillings contain mercury and that mercury is toxic for you. The short answer amalgam fillings are safe for you. The mercury in the amalgam is bound to other metals and elements so you will not ingest any significant mercury during the process of a filling.

If you have amalgam fillings and are concerned about them, removing them will expose you to more mercury than keeping them in place.

That being said, there are many other disadvantages to metal amalgam fillings (they can cause cracks in teeth) and that is why most private practices will not use them.