Most old amalgam fillings don’t need replacing. The ones that do, usually announce themselves through cracks, leaks, or visible decay around the margin.
If you’ve been told a long-standing silver filling should come out and be replaced with something tooth-coloured, it’s worth understanding why before you agree. Some replacement is genuinely warranted. Some isn’t. Our fillings service handles both routine replacement and assessment of older restorations, and we’d rather explain the reasoning than have a patient feel pressured into work they don’t need.
What Amalgam Is, and Why It’s Lasted So Long
Dental amalgam is an alloy of silver, tin, copper, and mercury, used as a restorative material since the mid-1800s. It’s been the workhorse of NHS restorative dentistry for the better part of a century, and there’s a reason: it’s strong, durable, relatively cheap, and forgiving of moisture during placement. A well-placed amalgam can last twenty to thirty years, sometimes longer.
The mercury content is what makes patients hesitate. Mercury is bound within the alloy in a stable form once the filling has set, but small amounts can be released through chewing wear over time. The clinical and regulatory consensus, as summarised in the long-running discussion on the dental amalgam controversy, is that placed amalgam is safe in the mouth for the vast majority of patients. Removing it for non-clinical reasons can actually expose patients to more mercury vapour than leaving it in place.
Worth knowing: that fact surprises most patients who come in asking for replacement.
When Replacement Is Genuinely Needed
There are several clinical signs that an old amalgam should be replaced. None of them are about age alone. Age, on its own, isn’t a reason to remove a filling that’s working.
- Visible fracture or crack in the filling itself
- Cracks in the surrounding tooth, particularly on the cusps
- New decay at the margin where the filling meets the tooth
- Recurrent food packing or sensitivity that wasn’t present before
- The filling has worn down significantly and no longer meets the opposing tooth properly
- Marginal staining that turns out, on closer examination, to be a leak rather than just discolouration
- The patient reports persistent dull ache or sensitivity to cold that traces to that tooth
If your dentist points to one of those, replacement is reasonable. If the only reason offered is the age of the filling or its appearance, we’d want a second opinion before agreeing.
The Cosmetic Replacement Question
Some patients want amalgam fillings replaced purely for aesthetic reasons. That’s a legitimate choice, and we don’t talk patients out of it. We do explain the trade-offs.
Replacing a sound amalgam with a composite involves removing the existing material, which inevitably takes a small amount of additional tooth structure with it. The tooth ends up slightly weaker afterwards, not because composite is inherently weaker (it isn’t, in modern formulations) but because the cavity preparation has been re-cut. This is sometimes called the restoration cycle: every time a filling is replaced, a little more tooth is lost.
That doesn’t mean you shouldn’t replace amalgams for cosmetic reasons. It means it’s worth doing the maths over the lifetime of the tooth.
A patient came to us recently who had eight amalgam fillings dating back to the 1990s. All of them were intact, none were leaking, and the patient was in their late forties with no symptoms. They’d seen advertising suggesting all amalgams should be removed for health reasons. We talked through the evidence, explained the restoration cycle, and they decided to leave six of the eight in place, replacing only the two that had visible marginal staining we wanted to investigate further. That seemed the right balance.
The Mercury Concern, Honestly Addressed
To put it precisely: amalgam contains roughly 50% mercury by weight, but once set, the mercury is chemically bound within the alloy. Some vapour is released by the very act of removing an amalgam filling, which is why modern dental practices use rubber dam, high-volume suction, and sometimes additional protective measures during removal.
The European Union introduced restrictions on amalgam use in pregnancy, breastfeeding, and in children under fifteen, and from January 2025 banned amalgam use across the EU entirely. The UK situation is slightly different post-Brexit, but the general clinical direction is towards composite for new fillings. Existing amalgams are not subject to mandatory removal.
The MHRA and NHS positions are aligned: don’t remove sound amalgam fillings unless there’s a clinical reason to do so.
Worth knowing: that position has held for decades and reflects the current weight of evidence.
How We Assess an Old Amalgam at Examination
At a routine check-up, we’d look at each existing amalgam in turn and assess several things. The visual margin first: is the filling sitting flush, or has it shrunk slightly with age? The bitewing X-ray next: is there any sign of decay underneath, or any darkness suggesting microleakage? Probing carefully: does the explorer catch on any rough edges? And finally, the patient’s symptoms: any sensitivity, any dull ache, any change since the last visit?
If everything looks and feels stable, we leave the filling alone. We note its age in the records and re-check it at the next examination.
It’s common for patients to ask whether we should replace fillings preventively, before they fail. We don’t, generally. The risk of cutting a sound restoration usually outweighs the benefit, and the new filling has its own lifespan that may not be longer than what’s already there.
Replacement Costs and What’s Involved
If replacement is needed, the procedure is straightforward, though slightly slower than placing a new filling because of the removal step. The table below sets out what’s typical.
| Stage | Time | What Happens |
|---|---|---|
| Anaesthetic | 5–10 minutes | Topical gel, then local injection; brief wait for full numbness |
| Isolation | 3–5 minutes | Rubber dam placed over the tooth being treated |
| Amalgam removal | 5–10 minutes | Old filling sectioned and lifted out under high-volume suction |
| Caries check and preparation | 5–10 minutes | Any decay underneath removed, cavity reshaped |
| Composite placement | 15–25 minutes | Bonding, layering, curing, polishing |
| Bite check | 3–5 minutes | Final adjustment |
For NHS patients in England, replacement of a single filling falls under Band 2, currently £76.60 for the course of treatment. The current band charges are listed at how much NHS dental treatment costs.
Privately, costs vary by practice and the size of the restoration. We’d quote on examination rather than over the phone, because the time involved depends on what’s underneath.
What to Expect Afterwards
Mild sensitivity for a few days is normal after any filling replacement. Cold sensitivity in particular tends to settle within a week, sometimes two. Persistent sensitivity beyond three weeks should be checked, because it can indicate either an over-filled bite (easily adjusted) or, less commonly, that the underlying tooth has had more inflammation than expected and may need further attention.
Most replacements are uneventful. Some take a little longer to settle than the patient hopes, but settle they generally do. In our experience, two weeks is the rough threshold beyond which lingering sensitivity should be reviewed rather than waited out.
It’s also worth saying something about replacement timing. If a patient has several amalgams that genuinely warrant replacement, we don’t usually do them all in one go. Spreading the work across two or three appointments lets us assess how each tooth settles before moving on to the next. That’s a small but meaningful detail of how good restorative dentistry tends to be sequenced.
And if you’re at all uncertain about what you’ve been advised, a second opinion is always reasonable. We’d rather you came in for a review and went away told everything’s fine, than have you replace work unnecessarily on someone else’s recommendation.
If you’d like an honest assessment of the amalgam fillings you’re carrying, our team at Westcliff Dental Practice in Westcliff-on-Sea is happy to talk through what’s actually warranted and what isn’t. Call us on 01702 344 500 and we’ll book you in for an examination.
