Old Fillings That Are Failing: When to Replace Them
An old filling that has cracked, chipped, stained or fallen out may be failing, commonly through new decay or fracture. Not every old filling needs replacing: each replacement can remove more tooth, so monitoring or repair is sometimes better. Have a dentist check any change; NHS guidance says see one as soon as possible if you think you have tooth decay.
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Clinically reviewed by Dr Ibraheem Ijaz, dentist · GDC 301711
Medical disclaimer: This page is for general information only. It does not replace an examination or treatment by a dentist.
Dr Ibraheem Ijaz, principal dentist at Deepcar Dental Care and a General Dental Practitioner, GDC 301711, reviewed this page.
How do old fillings fail?
Old fillings commonly fail (restoration failure) through new decay at the edges, called secondary caries, or through fracture of the filling or tooth.
A 1992 review by Kidd and colleagues called secondary caries the major reason restorations fail, and difficult to diagnose. Kidd later suggested it is no different from other decay except that it occurs next to a filling; our page on how cavities form explains decay.
A filling's edge can also wear or chip, leaving a small gap or ditch where it meets the tooth (marginal breakdown). Have a dentist check any filling that looks or feels different.
What are the signs an old filling is failing?
Signs include a cracked, chipped or lost filling, decay beside it, and toothache.
- A cracked, chipped or lost filling, or a gap at its edge: show it to a dentist. First steps are on our page about what to do if a filling falls out.
- Decay beside a filling, such as a hole, white, brown or black spots, or sharp pain with hot, cold or sweet food or drink: NHS guidance says see a dentist as soon as possible if you think you have tooth decay.
- Toothache, which NHS guidance says a loose or broken filling can cause: see a dentist, not a GP, if it lasts more than 2 days, does not go away with painkillers, or comes with a high temperature, pain when you bite, red gums, a bad taste, or a swollen cheek or jaw. If you have no dentist or cannot get an emergency appointment, call 111 or visit 111 online.
Go to A&E if you have toothache and the area around your eye or your neck is swollen, or swelling in your mouth or neck makes it difficult to breathe, swallow or speak. Do not drive to A&E: ask someone to drive you or call 999.
What is the restoration cycle?
The restoration cycle describes fillings being replaced again and again over a tooth's life, with each replacement tending to make the filling larger.
In 1,337 decisions to replace back-tooth fillings (Brantley and colleagues, 1995), 70% of the recommendations increased the number of filled surfaces; the authors suggested avoiding premature replacement, since it could hasten the cycle. A laboratory study of extracted premolars (Gordan and colleagues, 2002) found replacing white biting-surface fillings lost tooth structure.
Among filled back teeth, a 2004 study (Bader and colleagues) also strongly associated cusp fracture (a raised point of the tooth breaking off) with a detectable crack line in the enamel and a filling occupying more of the crown.
Kidd and colleagues' 1992 review says operative treatment cannot treat secondary caries away for good, and that preventive self-care is essential. So not all old fillings need replacing.
To ask about an old filling, book online or call 0114 288 2121.
When is replacing an old filling justified?
Replacement may be justified when there is decay beneath a filling, or when it has broken beyond a smaller repair. Show any such filling to a dentist.
In a laboratory study of 112 extracted filled teeth (Kidd and colleagues, 1994), a decay cavity at the filling's edge, or mineral loss on an X-ray, indicated soft, discoloured dentine beneath and should trigger operative treatment; a ditch alone should not.
A larger failure may need more than a new filling: NHS guidance says crowns can be fitted where a tooth has broken, decayed or been damaged. Our pages cover inlays and onlays for larger cavities and dental crowns.
When is monitoring better than replacement?
Monitoring or a smaller repair may suit a filling with a minor defect that is otherwise sound, with no decay beneath it.
A 2015 Dental Update paper (Green and colleagues) sets out "5 Rs" for deteriorating or failed fillings (review, reseal, refurbish, repair or replace), a minimally invasive approach that helps preserve natural tooth structure and pulp health for as long as possible.
Cochrane reviews describe repairing partly defective fillings as more conservative and sometimes possible without local anaesthetic, but their 2014 updates found no randomised controlled trials comparing it with replacement, for amalgam or white fillings.
Among 5,889 defective fillings (Gordan and colleagues, 2015), further treatment within 12 months was more likely after repair (7%) than replacement (5%), but repaired fillings were less likely to need aggressive treatment, namely replacement, root canal treatment or extraction. Have any chipped filling checked by a dentist.
Do old amalgam fillings need replacing?
Not necessarily. The European Commission's SCENIHR committee (2015) found no general justification for unnecessarily removing clinically satisfactory amalgam fillings, except in patients diagnosed as having allergic reactions to one of the amalgam constituents.
Northern Ireland's Department of Health said in 2019 that EU mercury rules, then applied UK-wide, were introduced for environmental reasons rather than any relating to the patient safety of amalgam fillings. Scottish Government guidance explains the rules ended amalgam use from July 2018 in baby teeth, children under 15 and pregnant or breastfeeding women, except where the dentist deems it necessary based on the individual patient's medical requirements.
Our page on how white fillings and amalgam compare covers the two materials.
Frequently asked questions
Are fillings available on the NHS?
Usually, NHS guidance says. In England, Band 2 (£76.60) may include fillings, and Band 3 (£332.10) may include crowns, inlays and onlays. If you need treatments from different bands, you pay the highest band's charge, and some people can get free NHS dental treatment.
Is dental amalgam being phased out?
Yes, under a global treaty. In 2025, parties to the Minamata Convention on Mercury agreed that after 2034 the manufacture, import or export of dental amalgam would not be allowed, except when a dentist considers its use necessary based on the patient's needs. The parties will review the need for that exception at their twelfth meeting.
What is cracked tooth syndrome?
It is a back tooth with an incomplete crack that causes symptoms, a 2010 British Dental Journal review explains. NHS guidance says see a dentist, not a GP, if you have chipped, cracked or broken a tooth; put any broken piece in milk or saliva and take it to the dentist, who may be able to glue it back on.
Does a stained edge around a filling mean decay?
Not reliably. In a 1996 clinical study around tooth-coloured fillings (Kidd and Beighton), neither staining nor ditching at the edge reliably predicted soft dentine beneath; in that study, only an obvious decay cavity at the edge reliably signalled secondary caries. Show any stained or ditched filling to a dentist.
Can a failing filling have no symptoms?
It can. Secondary caries is decay next to a filling, and NHS guidance says tooth decay may not cause symptoms at first. It advises regular check-ups even without problems, and a dentist visit if you have not had one for 2 years, or 1 year if under 18. Our page explains what a dental check-up includes.
Book a consultation.
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Deepcar Dental Care is at 334 Manchester Road, Deepcar, Sheffield, S36 2RH, and is open 8am to 8pm, Monday to Sunday.
Restorations at Deepcar Dental Care include white fillings, composite and ceramic inlays and onlays, and crowns. Services also include replacing old amalgam fillings with white fillings, replacing old discoloured fillings and treatment for a lost filling.
For restorative dentistry, our cost page explains what it costs, and patient feedback is on the practice's reviews page.
Other restorative signs are among the options in this section, and our page on repairing and rebuilding damaged teeth explains how restorative dentistry aims to keep natural teeth rather than replace them with implants.
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Deepcar, Sheffield S36 2RH
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