When you need a filling
Decay usually starts without pain. By the time a tooth hurts, the cavity is often deep. Signs to look out for:
- sensitivity to sweet, cold or hot that is getting worse
- food catching between two teeth in a new place
- a dark spot or a hole you can feel with your tongue
- a rough or broken edge on a tooth or old filling
- mild pain when you bite on something
Fillings are also used to repair small chips and to replace old fillings that have cracked or leak at the edges.
Filling materials
| Material | Looks | Best for |
|---|---|---|
| Composite (tooth-coloured resin) | Matches your tooth | Most fillings, front and back teeth, small chips and gaps |
| Glass ionomer (GIC) | Tooth-coloured, less polished | Milk teeth, fillings near the gum line, temporary fillings |
| Amalgam (silver) | Silver-grey | Rarely used now; old intact ones can be left in place |
When too much of the tooth is missing for a filling to hold, a crown or onlay protects it better. We will tell you if a filling is likely to be the weak option.
What happens
- Diagnosis. The dentist checks the tooth and, if needed, takes a small X-ray to see how deep the decay goes.
- Numbing. Gel on the gum, then a local anaesthetic.
- Removing the decay. Only the soft, decayed part is removed. Healthy tooth is left alone.
- Placing the filling. Composite is placed in layers and each layer is set with a blue light.
- Shaping and bite check. The filling is shaped, polished and checked with marking paper so your bite feels normal.
Most fillings are done in one visit. Several fillings can often be done together.
If the decay is deep
When decay is close to the nerve, we may place a protective lining under the filling and watch the tooth. If the nerve is already inflamed (lingering pain, pain at night), a filling alone won’t fix it, and root canal treatment may be needed. We’ll explain this before starting, not halfway through.
Looking after fillings
- Brush twice a day with fluoride toothpaste and clean between teeth every day. New decay at the edge of a filling is the main reason fillings fail.
- Cut down on how often you have sugary snacks and drinks; frequency matters more than amount.
- If you grind your teeth, ask about a night guard.
- Come for regular check-ups so a worn filling is replaced before the tooth breaks.
What affects the fee
The size of the filling, the number of surfaces it covers, the material, and whether the tooth needs a lining or extra build-up. Fillings on several teeth are quoted together. We give you the fee after examining the tooth.
Questions patients ask us
How long does a tooth filling last?
A tooth-coloured composite filling commonly lasts five to ten years and often longer. Small fillings last longer than large ones. Grinding, new decay around the edges and biting hard things are the usual reasons fillings fail.
Is getting a filling painful?
With local anaesthetic you shouldn't feel pain, only pressure and vibration. The injection itself is the part most people notice, and we numb the gum with gel first.
Why does my tooth hurt after a filling?
Some sensitivity to cold or biting for a few days, sometimes a couple of weeks, is common, especially with deeper fillings. Pain when you bite usually means the filling is slightly high and needs a quick adjustment. Pain that throbs, lingers after hot or cold, or wakes you at night can mean the nerve is inflamed, so come back and let us check.
Silver filling or white filling, which is better?
Most fillings today are tooth-coloured composite. It bonds to the tooth, needs less drilling and matches the colour. Silver (amalgam) fillings are hard-wearing but are now placed far less often. If you have an old silver filling that is intact and not causing problems, it doesn't need to be replaced just because it's silver.
Can a cavity heal without a filling?
A very early white spot on the enamel can sometimes be stopped with fluoride and better cleaning, and we'll watch it rather than drill. Once there is an actual hole, the decay won't heal by itself and needs a filling.
Can a filling fill the gap between front teeth?
Yes. Composite bonding can close small gaps and repair chips on front teeth in one visit, without drilling the tooth in most cases. See cosmetic dentistry for more on bonding.
What should I eat after a filling?
Wait until the numbness wears off so you don't bite your cheek or tongue. Composite fillings are fully set when you leave, so you can eat normally after that. Avoid very hard foods on a large new filling for a day.
Sources
ADA MouthHealthy: tooth-coloured fillings ↗NHS: tooth decay ↗NHS: dental treatments ↗Last updated 14 October 2026. This page explains options in general terms; your own plan comes from an examination.