Should I replace my metal fillings is a question I am asked several times a week, usually by someone who has noticed the dark shadows in their back teeth when they laugh. The honest answer, and it will not suit everyone, is: only if there is a reason to. A sound amalgam filling doing its job is often best left exactly where it is.
On this page
- The short answer
- When replacement is genuinely worthwhile
- When to leave them alone
- Are amalgam fillings safe?
- Replacing them for cosmetic reasons
- What goes in instead
- Practicalities if you do go ahead
- The bottom line
The short answer
Replacing a filling means removing it, and removing it means removing a little more of the surrounding tooth along with it. Every replacement makes the cavity slightly larger and the remaining tooth slightly weaker.
So the principle is straightforward: replace a filling when there is a clinical reason, or when you have decided you want it gone for appearance, having understood the trade-off. Do not replace one simply because it is old and metal.
When replacement is genuinely worthwhile
- The filling is cracked or fractured, which lets bacteria in underneath
- There is decay at the margin, visible clinically or on an X-ray
- The filling is leaking, with a gap opening at the edge
- It is worn down so it no longer meets the opposing tooth properly
- The tooth is cracked, which large amalgams can contribute to over decades
- You have symptoms, particularly pain on biting or lingering sensitivity
Any of these is a reason to act, and often the right answer is not another filling but something stronger. Our post on when a filling is too big explains why.
When to leave them alone
An amalgam filling that is intact, sealed at the margins, causing no symptoms and showing no decay on X-ray is doing precisely what it was placed to do. Some have been doing it for thirty years and will manage another ten.
Replacing it achieves nothing clinically, costs you money, and removes a little more of your tooth. I would tell you that plainly rather than book the appointment.
Be a little wary of any wholesale programme to replace all amalgam fillings on principle. Fillings should be assessed individually, on their own condition.
Are amalgam fillings safe?
This comes up often, so here is the position clearly.
Amalgam contains mercury bound into a stable alloy with other metals. UK and European health authorities consider amalgam fillings safe for the general population, and there is no evidence that having them removed improves general health in people without a specific allergy, which is rare.
There are some restrictions on its use, particularly for children, pregnant women and breastfeeding mothers, and the wider move away from amalgam is driven substantially by environmental concerns about mercury rather than patient safety.
Worth knowing: the process of drilling out an amalgam filling releases more mercury vapour than leaving it in place does. So removing sound fillings for health reasons is not the risk-free choice it might seem. If you have concerns, the honest conversation is worth having rather than acting on something read online. The NHS overview of dental treatments covers filling materials.
Replacing them for cosmetic reasons
This is an entirely legitimate reason, and I want to be clear about that after all the caution above.
If dark fillings show when you laugh and it genuinely bothers you, replacing them with tooth-coloured materials is a reasonable choice, and plenty of patients are delighted with the result. It is your mouth and your decision.
What you deserve is the full picture first: that a little more tooth is removed, that the new filling has its own lifespan, and that in a large cavity a white filling may not be the strongest option. Making that choice knowingly is quite different from being sold it.
A practical suggestion: replace them gradually, a few at a time, rather than all at once. It spreads the cost, and it lets you see how you feel about the result before committing to the lot.
What goes in instead
For small to medium cavities, a white filling is usually the direct replacement, bonded to the tooth and shade-matched.
For larger cavities, particularly where the old amalgam was extensive, a filling may not be the strongest choice. An inlay or onlay is custom-made and bonded in as one solid piece, and an onlay covers and protects the cusps. Where the tooth is seriously weakened, a crown is the answer.
Old amalgams tend to be in teeth that have been through a lot, so this conversation comes up more often than people expect.
Practicalities if you do go ahead
Expect some sensitivity for a few days to a couple of weeks afterwards, which is normal as the tooth settles. Our post on tooth sensitivity after a filling explains what is typical and what is not.
Deeper cavities occasionally turn out to be deeper than the X-ray suggested, and very occasionally a tooth that has been heavily filled for decades needs root canal treatment once the old filling is out. That is uncommon, but worth knowing before you start rather than hearing for the first time in the chair.
The bottom line
Replace metal fillings when they are cracked, leaking, decayed underneath, worn or causing symptoms, or when you have decided you want them gone for appearance and understand the trade-off. Do not replace sound ones on principle: they are considered safe, they are working, and removing them costs you tooth structure you cannot get back.
If you would like an honest assessment of which of yours actually need attention, ring us on 01255 422506. Our post on how often to visit the dentist explains how existing fillings are monitored over time.
This article is general information rather than personal dental advice. Every mouth is different, so please speak to your dentist about your own teeth.