A sound amalgam filling does not need replacing for its colour alone. Replacement is based on findings such as fracture, leakage or new decay.
If a silver filling has been in place for years without symptoms, it does not need to come out because of its colour. Leaving a sound amalgam alone is often the more conservative choice, since every replacement removes a little more healthy tooth and the new filling is always larger than the old one.
What amalgam is
Amalgam is an alloy of silver, tin, copper and mercury. It does not bond chemically to the tooth; it is packed into the cavity and held mechanically. That makes it less sensitive to moisture during placement and durable under heavy chewing loads, which is why it served for so long.
Its drawbacks are real too: it does not match tooth colour, it requires a retentive cavity shape, and it can shadow the tooth grey over time. Modern fillings are usually tooth-coloured, but that is not an argument for removing existing sound ones.
When replacement is justified
- A visible gap, chip or fracture at the margin.
- New decay under the filling on a radiograph.
- A crack in the surrounding wall, or sharp pain on biting.
- Surrounding tooth structure that has broken or thinned badly.
- Persistent sensitivity to hot, cold or sweet.
Replacing one for appearance
Swapping a visible amalgam for a tooth-coloured material is a reasonable personal preference. The only thing to understand is that it costs some tooth structure. For a sound filling at the back of the mouth, that trade-off is harder to justify.
About mercury
Mercury in amalgam is bound within the alloy. Public health bodies generally advise against removing sound amalgams wholesale, partly because removal itself increases short-term exposure. At the same time, many countries are phasing amalgam down for environmental reasons and avoid it in children and during pregnancy. Tell your dentist if you have a known metal allergy.
How replacement is done
The old filling is removed under water cooling and high-volume suction, the underlying tissue is cleaned and the remaining walls assessed. Loss beneath an old filling is often wider than expected; if the walls are weak, a cuspal-coverage restoration such as a zirconia crown may be advised.
In short: no findings, no rush; clear findings, act early. See our dental filling page for the available options.
