Metal to White Fillings
Many adults have a mouthful of silver-grey fillings placed years ago and wonder whether they should come out. Sometimes the honest answer is yes, and sometimes it's to leave well alone. Here's how to tell the difference.
Should I Replace My Amalgam Fillings with White Ones?
Replacing a metal (amalgam) filling is worth it when it is broken, leaking, has decay underneath or you want a tooth-coloured result, but there is no health reason to remove sound amalgam. At Comely Bank Dental in Edinburgh, white fillings start at £170, and a large old filling may be better replaced with a ceramic onlay at £800.
Should You Replace Your Metal Fillings?
Only if there's a good reason. A metal filling that is intact, sealed at its edges and sitting in a healthy tooth can carry on working for many more years, and taking it out always removes a little more tooth. On the other hand, an amalgam filling that has cracked, leaked or has decay creeping underneath needs replacing anyway, and at that point a white filling or onlay is the natural choice.
Appearance is a reasonable reason too. Plenty of people simply prefer not to see grey metal when they laugh, and that's a fair decision to make, as long as you understand what's involved and the small risks to the tooth.
What you shouldn't do is have sound fillings drilled out because you're worried they're harming your general health. The evidence doesn't support it: UK health bodies regard intact amalgam fillings as safe for the general population.
Are Amalgam Fillings Safe?
Dental amalgam is an alloy of silver, tin and copper bound together with mercury. Once set, the mercury is locked into a stable compound. Tiny amounts of vapour are released when you chew or grind, but the levels are well below those known to cause harm.
The position of UK and international health bodies is that, for the general population, amalgam fillings are safe and there is no need to remove sound amalgam for health reasons. Drilling one out actually releases more mercury vapour in the short term than leaving it in place.
There are a few genuine exceptions:
- True allergy to amalgam is rare, but it does happen
- Lichenoid reactions, white or red patches on the cheek or tongue directly touching a filling, can sometimes settle once that filling is replaced
- Some guidance suggests avoiding new amalgam for people with significantly reduced kidney function
If you've been told your symptoms are caused by your fillings and you're not sure, talk it over with us. We'll give you a balanced view rather than either dismissing your concern or selling you treatment.
Want Your Old Fillings Checked?
Book an examination and we'll tell you which fillings, if any, need attention, and which are best left in place. Fees are agreed in writing before any treatment.
Why Is Amalgam Being Phased Down?
The main reason is environmental. Mercury that leaves dental practices, crematoria and waste can build up in rivers and the food chain. The UK is part of the Minamata Convention, an international treaty to reduce mercury use, and the use of dental amalgam is being steadily phased down as part of it.
Since July 2018, the rules have been that amalgam should not be used for:
- Baby teeth
- Children under 15
- Women who are pregnant or breastfeeding
unless the dentist judges it strictly necessary for a specific medical reason. These are precautionary measures, not a sign that existing fillings in adults are dangerous.
If you're pregnant or breastfeeding, it's sensible to postpone any non-urgent replacement of amalgam until afterwards, because removal briefly increases exposure. A filling that has broken or is causing pain can still be dealt with, and we'll plan the safest way to do it.
Tooth-coloured materials are increasingly used in place of amalgam, and amalgam waste from dental practices has to be captured and disposed of under strict regulations.
Good Reasons to Replace a Metal Filling
At a dental examination we examine each filling and take X-rays where needed. These are the findings that usually mean a filling should be replaced:
- Decay under or beside the filling, often visible on an X-ray before you notice anything
- A gap or ditch at the edge, where food and bacteria can get in
- A fracture in the filling itself
- Cracks in the tooth around it, particularly where a large amalgam has acted like a wedge over the years
- A broken cusp next to the filling
- Sensitivity or pain that we can trace to that tooth
- Appearance, if a visible filling bothers you
Old amalgam can also leave the surrounding tooth looking grey. Replacing the filling often improves this, but some staining is in the tooth itself and may not disappear completely, so it's worth knowing in advance.
When Is It Better to Leave a Metal Filling Alone?
Replacing a filling is not risk-free. Each time a filling comes out, the cavity becomes slightly bigger, because some sound tooth inevitably comes away with the old material. In a deep filling, the work also takes place close to the nerve.
For most people this goes smoothly. But a small proportion of teeth become sensitive afterwards, and occasionally a nerve that was already under strain doesn't recover and needs root canal treatment. That risk is higher with very large, deep fillings.
So we'd usually advise leaving an amalgam alone when:
- It's intact, well sealed and shows no decay on X-ray
- It's at the back of the mouth and doesn't bother you cosmetically
- It's very large and deep, and the tooth is comfortable
We'd rather tell you a filling is fine than replace something that isn't causing a problem. If you're replacing for appearance, we'll usually suggest starting with the fillings you can actually see.
White Filling or Onlay: What Replaces a Large Amalgam?
For small and medium cavities, a composite (white) filling is usually the right replacement. It's bonded to the tooth, which helps seal the edges and lets us remove less healthy tooth than amalgam ever needed.
Large amalgams are a different matter. Many were placed in an era when big metal fillings were routine, and the tooth around them may now be thin, cracked or missing a cusp. Here the choice is between a large composite filling and a laboratory-made ceramic onlay.
| Feature | Large white filling | Ceramic onlay |
|---|---|---|
| Visits | One | Usually two |
| Protects weak cusps | Limited | Yes, covers them |
| Wear and chipping over time | More likely in big cavities | More resistant |
| Fee | £250 | £800 |
If the walls are strong, a large white filling can do well. If they're thin or cracked, an onlay holds the tooth together and is often the better long-term option. Our patient guides include one on choosing between a crown, onlay or filling, which explains this in more detail.
What Happens When a Metal Filling Is Replaced?
The appointment is very similar to having any filling done:
- Numbing. The tooth is anaesthetised so the procedure is comfortable.
- Isolation. Where possible we place a rubber dam, a thin sheet that isolates the tooth, with high-volume suction to keep it dry and capture debris.
- Removal. The amalgam is cut out in sections with plenty of water cooling, which keeps vapour and dust to a minimum.
- Checking the tooth. Any decay is removed and we look for cracks. Occasionally this changes the plan, and we'll talk to you before going ahead with anything different.
- Restoring. A composite filling is bonded in layers and set with a light, then shaped to your bite and polished. For an onlay, the tooth is scanned with our iTero scanner, a temporary is placed and the onlay is fitted at a second visit.
Most people have one or two fillings replaced per visit. If you'd like several done, we'll usually plan them side by side over a few appointments.
How Will the Tooth Feel Afterwards?
The numbness wears off within a few hours. After that, it's common for a newly filled tooth to feel slightly sensitive to cold or when biting for a few days, sometimes a couple of weeks, and then settle.
Contact us if:
- The bite feels high or the tooth is sore every time you close together
- Sensitivity is getting worse rather than better
- You have a throbbing or lingering ache
A high spot is easily adjusted. Persistent pain needs checking, as it can mean the nerve is struggling. Our aftercare page has general advice for after fillings.
How Much Does It Cost in Edinburgh?
Fees at our Comely Bank practice depend on the size of the filling:
- Small white filling: £170
- Medium white filling: £220
- Large white filling: £250
- Ceramic onlay: £800
We'll tell you which size each filling is likely to be before we start, though a large old filling can sometimes turn out bigger once it's out. All fees are guide prices, confirmed in a written treatment plan before treatment, and members of our dental plan save 10% on most private treatment. You can see our full price list on the fees page.
Questions
This guide is general information, not a diagnosis. A dentist needs to examine you to say what is right for your teeth.