How Long Do Fillings Last? And Why a New Filling Feels Sensitive

Fillings feel permanent, which is exactly why their eventual failure catches people out. Every filling is a repair in a wet, warm environment that gets bitten on a few thousand times a day, and like any repair it has a working life. Knowing roughly what that life is, what shortens it, and what a new filling should and should not feel like takes most of the surprise out of the whole business.

The short answer

As broad working figures, white composite fillings typically last 5 to 10 years and silver amalgam fillings 10 to 15, with plenty lasting far longer and some failing sooner. The spread is mostly about you rather than the material: the size of the filling, where it sits, grinding, diet and cleaning move the numbers a long way in both directions. And a new filling feeling sensitive to cold or pressure is normal, settling over two to four weeks. Sensitivity that is worsening after that, or pain on biting that persists, is worth a call rather than patience.

What decides how long a filling lasts

Size and position. A small filling in a groove has an easy life. A large filling rebuilding half a molar takes full chewing force across a wide bond line, and the more tooth a filling replaces, the shorter its odds. There comes a size where a filling is the wrong tool and a crown protects the tooth better, and a good dentist tells you when a tooth has crossed that line.

The material. Amalgam is mechanically tough, which is much of its longevity record. Modern composite has closed a lot of the gap and bonds to the tooth rather than merely sitting in it, and it is the standard for visible teeth. Our guide to white filling costs covers the choice; here amalgam starts from £95 and composite from £125.

Grinding. The filling killer. Clenching and grinding, covered in our bruxism guide, chips composite edges and cracks the tooth around any filling. If your fillings keep failing and your jaw aches in the morning, the fillings are the symptom, not the problem.

Decay around the edges. The most common actual cause of failure is not the filling wearing out but new decay creeping in at the margin where filling meets tooth. That margin is a plaque trap, which is why cleaning and sugar frequency decide filling lifespans as much as materials do, and why check-ups examine old fillings, because margin decay caught early means replacing a filling rather than a root canal.

Time and load. Fillings do not have a expiry date, and a sound old filling is left alone. They are replaced when they leak, chip, crack or hide new decay, not because a birthday arrives.

Why new fillings feel sensitive, and when to worry

After a filling, the tooth has been drilled, dried, etched and rebuilt, and the nerve inside registers the disturbance. For the first days to weeks, brief sensitivity to cold, sweet things or first bites is completely normal, especially with deeper fillings where the work happened closer to the nerve. It fades as the nerve settles, usually within two to four weeks, occasionally longer for deep fillings. A desensitising toothpaste helps in the meantime, and our sensitive teeth guide covers the wider subject.

Three patterns are not normal, and each has a simple fix when caught early. Pain on every bite usually means the filling is sitting a fraction high, and a thirty-second adjustment cures it; do not wait that one out, because a high filling bruises the tooth beneath. Sensitivity that worsens week on week rather than fading suggests the nerve is not settling, and needs a look. A sharp edge, rough patch or catching floss means the filling needs smoothing or refinishing. None of these mean the filling has failed; all of them mean ring rather than endure.

What replacement costs, and the honest economics

Replacing a filling costs the same as having one: from £95 for amalgam, £125 for composite here, with everything published on our fees page. If a filling has fallen out entirely, our guide on what to do when a filling falls out covers the interim. The economics worth knowing: each time a filling is replaced, a little more tooth goes with it, so fillings do not get replaced indefinitely. A tooth on its third large filling is usually heading for a crown, from £600, and planning that deliberately beats meeting it as an emergency. Check-ups are how that planning happens, £89 for new patients including X-rays, and X-rays are precisely how margin decay under old fillings is found before it hurts.

Frequently asked questions

How long do white fillings last?

Typically 5 to 10 years, with well-maintained small fillings often lasting well beyond that. Size is the biggest factor: large composites doing structural work fail sooner than small ones in grooves. Grinding, sugar frequency and cleaning around the filling move the figure substantially in both directions.

How long should a filling be sensitive for?

Brief sensitivity to cold or biting is normal for two to four weeks after a filling, longer for deep ones, and it should be fading rather than building. Pain on every bite suggests the filling is slightly high and needs a quick adjustment. Sensitivity that worsens after the first month needs looking at.

How do I know when a filling needs replacing?

Often you do not, which is the point of check-ups: margin decay and hairline cracks show on examination and X-ray before they cause pain. Signs you can notice yourself include a chipped or rough edge, food packing where it never used to, new sensitivity around an old filling, or floss shredding at one spot.

Do fillings need replacing when they get old?

No. Age alone is not a reason, and a sound, sealed old filling is left exactly where it is. Fillings are replaced for leaks, fractures, lost pieces or decay at the margins. Routine replacement of intact fillings removes healthy tooth for no benefit.

Filling due a check?

If a filling is chipped, sensitive or simply old enough that you wonder, a check-up answers it properly. Call 01625 574609. New patient examinations are £89 including X-rays, fillings from £95, all on our fees page.

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