Fillings wear out and fail over time, usually between 5 and 30 years depending on the material and how hard you chew
Dental fillings are not permanent. The material breaks down from constant chewing, temperature changes in your mouth, and the natural wear of daily use. A filling that is working fine today may develop a gap, crack, or decay underneath it in five years or fifteen years. Your dentist checks for these problems during routine exams—that is the main reason they look closely at old fillings and take X-rays around them.
The timeline varies sharply by material. Amalgam (silver) fillings typically last 10 to 30 years. Composite (tooth-colored plastic) fillings usually last 5 to 15 years. Glass ionomer fillings, often used on baby teeth or below the gum line, may last 5 to 10 years. Gold fillings can last 20 to 30 years but are expensive. The location of the filling matters too—fillings on back teeth that take the force of chewing wear faster than those on front teeth.
Key Takeaways
- Fillings fail when they crack, chip, or develop gaps that let bacteria underneath, and your dentist spots these problems during checkups using visual inspection and X-rays.
- Composite fillings typically last 5 to 15 years, while amalgam fillings last 10 to 30 years, so the age of your filling is one clue but not the only one.
- Decay under a filling is the most common reason for replacement, and it happens because bacteria slip past the edges when the seal breaks.
- You may not feel pain or notice anything wrong, which is why regular dental visits catch failing fillings before they cause problems.
Signs a filling is failing and needs replacement
A filling that is breaking down usually shows one or more of these signs. You might feel a rough edge with your tongue, see a visible crack or dark line around the filling, or notice that food gets stuck in the same spot repeatedly. Some people feel sensitivity to hot or cold near an old filling, which suggests the seal is compromised. A filling can also straightforward fall out or chip away, leaving a hole you can see or feel.
Decay underneath a filling is harder to spot on your own because it happens below the surface. This is why X-rays are important—they show decay that your eyes cannot see. If decay spreads under the filling, you might not have any symptoms until the cavity is large enough to cause pain or the filling fails completely. Your dentist will tell you during a checkup if they see decay on an X-ray around an old filling.
How dentists decide whether to replace a filling
Your dentist does not automatically replace every filling that is ten years old. They look at the filling itself—is it intact, or does it have cracks, gaps, or rough edges? They check the tooth underneath using X-rays to see if decay has started. They also ask about your symptoms: Do you feel pain, sensitivity, or food trapping? Have you noticed anything loose or rough?
If the filling is solid, the tooth underneath is healthy, and you have no symptoms, your dentist will likely leave it alone and monitor it at your next visit. If there is a crack, a gap, visible decay on the X-ray, or you are having symptoms, replacement is usually recommended. Sometimes a filling can be patched or repaired rather than fully replaced, but this depends on how much of the original filling is still sound.
What happens during filling replacement
Replacement is similar to the original filling procedure. Your dentist numbs the tooth with local anesthetic, removes the old filling and any decay underneath it, cleans the space, and fills it again with new material. The whole process usually takes 20 to 60 minutes depending on the size of the filling and whether decay removal takes longer than expected.
If decay has spread deep into the tooth, the dentist may find that a straightforward filling will not hold. In that case, they might recommend a crown instead, which covers the whole tooth. This decision happens during the procedure—your dentist cannot always know how much decay is present until they remove the old filling and look inside.
Choosing a material for your replacement filling
When you replace a filling, you have a choice of materials. Composite (tooth-colored) fillings match your natural tooth and look better, especially on front teeth. They bond directly to the tooth and require less drilling away of healthy tooth structure. The trade-off is that they do not last as long as amalgam and cost more.
Amalgam (silver) fillings are durable, less expensive, and work well on back teeth where appearance matters less. They last longer than composite but require more of the healthy tooth to be removed during placement. Some people avoid amalgam because it contains mercury, though the American Dental Association considers the amount used in fillings to be safe. Glass ionomer fillings are weaker and used mainly on baby teeth or below the gum line. Your dentist can explain which material makes sense for your specific tooth and situation.
How to extend the life of your fillings
You cannot stop fillings from eventually wearing out, but you can slow the process. Brush twice a day with fluoride toothpaste and floss daily to keep decay from starting around the edges of the filling. Avoid chewing on hard objects like ice, hard candy, or pen caps—these crack fillings faster. If you grind your teeth at night, ask your dentist about a night guard, which protects fillings from the constant pressure.
See your dentist every six months for a checkup. These visits let your dentist catch problems with fillings before they become serious. If you notice a crack, rough edge, or sensitivity around an old filling, call your dentist rather than waiting for your next scheduled visit. Early treatment of a small problem is simpler and cheaper than waiting for the filling to fail completely.
Frequently Asked Questions
How do I know if my filling is failing?
Common signs include a rough or jagged edge you can feel with your tongue, visible cracks or dark lines around the filling, food getting stuck in the same spot, or sensitivity to hot or cold. Some fillings fail silently with decay underneath, which is why regular dental checkups and X-rays matter. If you notice anything unusual, contact your dentist.
Can a filling last forever?
No. Even the most durable fillings eventually wear out from chewing, temperature changes, and normal use. Amalgam fillings may last 20 to 30 years, but composite fillings typically last 5 to 15 years. Your dentist monitors them during checkups and recommends replacement when they show signs of failure.
Is it painful to have a filling replaced?
No. Your dentist numbs the tooth with local anesthetic before starting, so you should feel pressure and vibration but not pain. You may feel some sensitivity for a day or two after the procedure, especially to cold, but this usually fades quickly. If you have pain after a few days, contact your dentist.
What happens if I ignore a failing filling?
Decay can spread underneath and into the tooth, eventually reaching the nerve and causing an infection. This may require a root canal, which is more expensive and time-consuming than a straightforward filling replacement. Ignoring a failing filling also risks the filling falling out completely, leaving the tooth exposed to further damage.
Do all my old fillings need to be replaced at once?
No. Your dentist replaces fillings one at a time as they fail or show signs of problems. If you have multiple old fillings, your dentist will prioritize the ones that are cracked, leaking, or have decay underneath. Healthy fillings are left alone and monitored at future visits.