How Long Does a Cavity Filling Last: Lifespan, Wear, and Replacement Signs

Short answer

• A cavity filling is not usually permanent, but it is not short lived either. Most fillings last for years, and many last a decade or longer. As a broad guide, amalgam (silver) fillings commonly last about 10 to 15 years and sometimes longer, tooth colored composite fillings average roughly 5 to 10 years, gold fillings can last 20 years or more, ceramic fillings often last around 15 years, and glass ionomer fillings, the weakest of the group, typically last about 5 years or less. These are typical ranges drawn from clinical summaries, not promises for any individual tooth. A filling in a heavily loaded back molar, in a mouth that grinds at night, can fail years earlier than the same material in a small front tooth filling that is well cared for. A filling usually ends its life in one of a few ways. It can wear down, chip, or crack under chewing forces. Its edge can open a microscopic gap that lets bacteria in, so new decay starts underneath or around it. Or the tooth itself can develop a new problem, such as a crack or fresh decay elsewhere, that makes the old repair unsalvageable. Warning signs include new or worsening sensitivity, pain when biting, a rough edge your tongue keeps finding, food trapping around the filling, or a visible crack or missing piece. Regular dental checkups matter because a dentist can often spot wear or leakage at an exam, sometimes with X-rays, before the filling hurts. This article is general information only. It does not diagnose any individual tooth, and it cannot tell you how long your own filling will last. Only your dentist, who can examine the filling and the tooth around it, can judge its condition. What this article can do is explain the typical lifespans by material, the factors that shorten or extend them, the signs that a filling needs attention, and what replacement involves, so you know what questions to ask at your next appointment.

What a Filling Does, and Why It Cannot Last Forever

A filling repairs a tooth after decay has been removed. Cleveland Clinic describes dental fillings as a restorative treatment used to repair cavities and to fix minor chips and cracks: the dentist removes the damaged or decayed part of the tooth and replaces it with a sturdy material that seals the hole and restores the tooth’s shape. That seal is the filling’s whole job. It keeps bacteria and food debris out of the cleaned cavity and lets the tooth bear chewing forces again.

The reason no filling lasts forever is that the seal lives in a hostile environment. A filled tooth is heated and cooled by food and drink many times a day, loaded with chewing pressure thousands of times, and bathed in the acids that mouth bacteria produce from sugars and starches. The filling material and the natural tooth around it do not expand, contract, and wear at exactly the same rate, so the junction between them, called the margin, is under constant slow stress. Over years, that margin can open slightly, stain, or crumble. Mayo Clinic makes the same point from the decay side: over the years, dental fillings can weaken, begin to break down, or develop rough edges, which lets plaque build up more easily and makes it harder to remove.

It also helps to know that dentists divide fillings into two families. Direct fillings are built up inside the tooth during a single visit; Cleveland Clinic lists amalgam, resin composite, and glass ionomer as the common direct materials. Indirect fillings, such as gold or porcelain inlays and onlays, are made by a dental technician in a laboratory and then fitted to the tooth, usually across two visits, although some practices can design and mill them in one appointment. Indirect restorations tend to sit at the long lasting, higher cost end of the spectrum, because they are precision made for one tooth and cemented into place.

How Long Each Filling Material Typically Lasts

Material is the single biggest predictor of lifespan, because the materials differ in strength, wear resistance, and how they bond to the tooth. The ranges below are the typical figures reported in a clinical summary of American Dental Association (ADA) material guidance, cross checked against the ADA’s own MouthHealthy information. Read them as averages across many mouths. Your filling’s actual life depends on the factors in the next section.

Material	Typical lifespan	Where it is usually used
Amalgam (silver)	10 to 15 years, sometimes 20 or more	Back teeth and large cavities under heavy chewing load
Composite resin (tooth colored)	About 5 to 10 years; ADA summaries put the average near 7	Front teeth and small to medium cavities anywhere appearance matters
Gold	20 years or more; reported ranges run to 30	Back teeth, where maximum durability matters more than looks or cost
Ceramic (porcelain)	Around 15 years, often quoted as 10 to 15 or more	Inlays and onlays, and visible teeth where appearance matters
Glass ionomer	About 5 years or less	Small cavities near or below the gumline, children’s teeth, and low stress areas

Amalgam

Amalgam is the silver colored mixture of metals, including silver, copper, tin, zinc, and mercury, that dentists have used for more than a century. The ADA’s MouthHealthy site lists its strengths plainly: it is durable, it hardens quickly, it tolerates areas that are hard to keep dry during placement, and it is the least expensive filling material. Those qualities made it the standard choice for large cavities in back molars, where chewing force is greatest. Its typical lifespan is 10 to 15 years, and well placed amalgam fillings in favorable conditions can run to 20 years or beyond. Its drawbacks are appearance, since the silver color shows, and preparation, since a dentist may need to remove more tooth structure to place it securely. If you have older silver fillings and wonder about the mercury question, our explainer on mercury dental amalgam fillings and what the FDA guidance actually says covers it in detail. The ADA’s position is that a sound amalgam filling does not need to be removed just because it is amalgam.

Composite resin

Composite is the tooth colored material, a resin base mixed with powdered quartz, silica, or glass, that is bonded directly to the tooth and hardened in layers. Because it can be shade matched, it is the default choice for front teeth and for any filling that shows when you smile. ADA summaries put its average lifespan at about 5 to 7 years, with broader clinical ranges of 5 to 10 years; small composite fillings in low stress positions, in mouths with good hygiene, can last 10 years or more. Composite generally wears faster than amalgam under heavy chewing pressure, which is why very large composite fillings in back molars tend to have shorter lives than small ones. It also stains more readily than ceramic over time.

Gold

Cast gold fillings and gold inlays or onlays are the durability benchmark. Gold does not corrode, it wears at a rate close to natural tooth, and it is gentle on the opposing teeth. Reported lifespans start at around 15 to 20 years, the ADA attributed average is 20 years or longer, and ranges up to 30 years are commonly cited. The trade offs are cost, since gold is usually the most expensive option and can cost several times more than amalgam, visibility, and process: because the restoration is made in a laboratory, it normally takes at least two appointments.

Ceramic and porcelain

Ceramic fillings, most often porcelain inlays and onlays, are tooth colored like composite but are made in a laboratory or milled from a solid block, which makes them denser and more wear resistant. Typical lifespans are around 15 years, with 10 to 15 years or more quoted across clinical summaries. Ceramic resists staining better than composite, so it keeps its appearance well. It can cost as much as gold, and because porcelain is somewhat brittle, a ceramic restoration can fracture under extreme or sudden load rather than wearing gradually.

Glass ionomer

Glass ionomer is a tooth colored material made from silica glass powder and acrylic type acids. It is the weakest filling material in this list and typically lasts about 5 years or less, which is why dentists reserve it for places that carry little chewing load: small cavities on root surfaces near or below the gumline, fillings in children’s teeth, and temporary or intermediate repairs. It has one compensating virtue. Glass ionomer releases fluoride over time, which can help protect the surrounding tooth against further decay, a useful property in patients at high risk of new cavities.

What Affects How Long a Filling Lasts

Two fillings placed on the same day, in the same mouth, can age very differently. These are the factors dentists weigh when they judge how much life a filling has left.

Where the filling sits

Back teeth, especially molars, do most of the grinding work of chewing and take forces many times greater than front teeth. A filling on a chewing surface of a molar lives a harder life than a small filling on the smooth side of a front tooth. Fillings that wrap around a corner of the tooth or replace a whole cusp are under more stress again, because less natural tooth remains to share the load.

How big the filling is

A small filling is mostly supported by sound tooth around it. A large filling reverses that relationship: the filling becomes most of the tooth’s chewing surface, and the thin walls of remaining tooth flex under load. Large fillings wear faster, crack more readily, and leave the tooth itself more vulnerable to fracture. This is one reason a dentist may suggest a crown instead of another filling when a tooth has been filled several times.

Grinding and clenching

Bruxism, grinding or clenching the teeth, often during sleep, multiplies the forces a filling must survive and is one of the fastest ways to shorten its life. It can crack filling material, chip the tooth at the filling’s edge, and wear the surface flat. If you grind, tell your dentist: a night guard, and sometimes a different material choice, can protect both the filling and the tooth.

Diet and habits

Frequent sugary or acidic food and drink feed the bacteria whose acids attack the tooth at the filling’s margin, which is where new decay usually starts. Hard habits matter mechanically too: chewing ice, pens, or hard candy, opening packaging with your teeth, and biting nails all concentrate force on filling edges. None of these will necessarily break a filling on one occasion, but repeated over years they add up.

Hygiene and new decay at the edges

The most common reason fillings fail is not the material wearing out but new decay forming at the margin, sometimes called recurrent or secondary decay. Bacteria entering a tiny gap at the edge can hollow out the tooth underneath a filling that still looks intact from above. Brushing twice a day with fluoride toothpaste and cleaning between the teeth attack exactly this risk. The ADA’s prevention advice for avoiding fillings in the first place is the same advice that protects existing ones: brush twice daily with fluoride toothpaste, clean between your teeth every day, eat balanced meals low in added sugar, limit snacking, drink water, and visit your dentist regularly. Our explainer on how sugar leads to tooth decay, and why frequency matters most, explains the acid attack pattern behind margin decay.

How well it was placed, and the tooth underneath

Placement quality matters. A filling placed in a dry, well isolated field bonds and seals better than one placed under difficult conditions, which is one reason amalgam, which tolerates moisture during placement, earned its reputation in awkward spots below the gumline. Finally, the tooth itself sets a ceiling: a tooth weakened by a very deep cavity, a crack, or previous root canal treatment may fail around a filling that is itself still sound.

Signs a Filling May Be Failing

A failing filling often announces itself, but the signs are easy to dismiss. Any of the following deserves a dental appointment rather than a wait and see approach:

• New or returning sensitivity to hot, cold, or sweet things in a tooth that had settled down.
• Pain when biting or chewing, especially a sharp twinge when you bite on one spot, or pain that releases as you let go.
• A rough, sharp, or jagged edge that your tongue keeps finding, or a filling that suddenly feels different.
• Food trapping in the same place after meals, or floss that catches, shreds, or will not pass a spot it used to pass.
• A visible crack in the filling or the tooth, dark staining spreading at the filling’s edge, or a piece that has chipped away.
• A filling that feels loose, moves, or falls out altogether.
• A bad taste or bad breath localized around one tooth, which can accompany decay under a filling. Our article on whether cavities cause bad breath explains that connection.

Not every warning sign means the filling is finished. Sensitivity in the first days after a new filling is common and usually settles, and a filling that feels slightly high can often be fixed with a quick bite adjustment. The next section separates normal settling from genuine red flags. It is also worth knowing that a filling can be failing with no symptoms at all, which is why dentists probe filling margins and take periodic X-rays at checkups: decay under a crown or filling may only show on an image. If you are wondering what decay itself feels like as it develops, see what does a cavity feel like.

Sensitivity After a New Filling: What Is Normal and What Is Not

Some sensitivity after a filling is expected. The tooth has been drilled, and if the cavity was deep, the nerve inside the tooth sits close to the new filling and can react to cold, heat, and pressure while it calms down. Mild sensitivity that is improving week by week, and that fades within seconds of the trigger being removed, is the usual pattern. Numbness from the local anesthetic wears off within a few hours, and dentists generally advise not chewing on the numb side until feeling returns, because it is easy to bite a cheek or tongue you cannot feel.

The pattern matters more than the presence of sensitivity. Sensitivity that is getting worse rather than better, pain that lingers for a long time after hot or cold is removed, spontaneous pain that arrives without any trigger, pain that wakes you at night, swelling of the gum or face, or a bad taste near the tooth are not normal settling. Those can point to a bite problem, a cracked tooth, decay left near the nerve, or the nerve itself becoming inflamed, and they need examination. Sensitivity that simply refuses to settle after several weeks should also be reported rather than endured. A dentist can test the bite, check the filling, and take an X-ray to see what is happening under it, then decide between monitoring, adjusting, repairing, or replacing.

What Replacing a Filling Involves

Replacement is similar to getting the original filling, with one extra step. The dentist numbs the area if needed, removes the old filling material along with any new decay that has formed under or around it, cleans and reshapes the space, and places a new filling, either directly in that visit or, for an indirect restoration such as an inlay, onlay, or crown, after a laboratory step. If the bite feels high afterward, a short follow up adjustment is routine.

Two honest caveats belong here. First, every replacement makes the cavity slightly larger, because the dentist must remove the old material and any softened tooth around it. A tooth can only be refilled so many times before the remaining structure cannot support another filling, which is when a crown or another restoration enters the conversation. Our guide to crown, bridge, and filling aftercare covers what to do after restorative treatment of any of these kinds. Second, replacement is not always the answer. Small defects at a filling’s edge can sometimes be repaired or resealed rather than replaced wholesale, and a sound filling should not be replaced just because it is old, or just because it is amalgam. Age alone is not failure. The decision rests on the margin’s integrity, the presence of decay or cracks, and your symptoms, all of which your dentist assesses at the appointment.

How to Help a Filling Last Longer

You cannot make a filling permanent, but the evidence based habits below protect the margin, which is where most fillings are lost:

• Brush twice a day with fluoride toothpaste and clean between your teeth daily with floss or interdental brushes. This is the ADA’s core prevention advice, and it directly lowers the risk of decay starting at a filling’s edge.
• Cut the frequency of sugar and acid. It is how often teeth meet sugar, not only how much, that drives decay. Keep sugary and acidic drinks to mealtimes where you can, and choose water between meals.
• Do not use your teeth as tools. Avoid chewing ice and very hard foods on filled teeth, and never open bottles or packaging with them.
• Ask about a night guard if you grind. Protecting fillings from sleep grinding removes one of the largest sources of avoidable stress.
• Keep regular dental checkups. A professional cleaning reaches places home care misses, and an examination catches worn margins, early cracks, and new decay while repair is still simple. Professional polishing is part of that maintenance; our article on what teeth polishing does and when it helps explains what it can and cannot do.
• Report changes early. A rough edge, a new sensitivity, or food starting to catch are cheap problems at the appointment where they are first noticed, and expensive ones a year later.

When to See a Dentist Promptly

Book an appointment soon, rather than waiting for a routine checkup, if a filling falls out, if a tooth cracks, if you have pain when biting that persists beyond a day or two, if sensitivity is worsening or lingers long after the trigger is gone, or if you notice swelling, a bad taste, or a pimple like bump on the gum near a filled tooth. If a filling comes out, keep the area clean, avoid chewing on that side, and call your dentist for advice; the exposed tooth can be sensitive and is unprotected until it is repaired. Seek urgent care the same day for facial swelling, fever alongside tooth pain, or difficulty opening your mouth, swallowing, or breathing, since those can signal a spreading infection. If neglected decay is what brought a filling to the end of its life, our explainer on how cavities turn into root canals describes the path dentists work to interrupt early.

Two Related Questions That Are Not About Filling Lifespan

Two questions are often grouped with this topic but ask something different, and confusing them leads to bad decisions.

How long can you wait before filling a cavity? That is a treatment timing question, not a lifespan question. A cavity does not heal on its own; once decay has broken through the enamel into a hole, it generally progresses, and delay can turn a small filling into a large one, a crown, or root canal treatment. If a dentist advises a filling, ask about timing at that appointment rather than deciding from a general article. Our guide to how to get rid of cavities and what a dentist actually does covers the treatment options by stage.

How long does a cavity itself last if untreated? A cavity has no fixed lifespan either. Untreated decay usually worsens over time, at a speed that varies with diet, hygiene, and the tooth, which is precisely why early treatment matters. Filling lifespan, how long a repair survives, should never be confused with cavity duration, how long decay can be left.

Frequently Asked Questions

Are cavity fillings permanent?

No. No filling material lasts forever, and the ADA’s guidance is explicit that longevity depends on the material and the patient’s habits. Many fillings serve for a decade or more, and gold can serve for two or three decades, but every filling should be regarded as a long lasting repair that will probably need replacement one day, not as a permanent fix.

How long does a temporary filling last?

Temporary fillings are a different product with a different job: they seal a tooth for a short interval, for example between stages of treatment. Clinical summaries put their life at roughly 6 to 8 weeks. They are softer and weaker than permanent materials, so a temporary that is still in place after a couple of months, or that breaks or falls out, needs a call to your dentist rather than patience.

Do fillings wear out even if they do not hurt?

Yes. Wear, margin breakdown, and decay under a filling can all progress silently. Pain is a late signal, not an early one, which is why filling condition is checked at routine examinations and why X-rays are taken periodically even when nothing hurts.

Should I replace my old amalgam fillings with white ones?

Not automatically. The ADA states that existing amalgam fillings are safe and do not need to be removed while they are in good condition, and every replacement removes a little more tooth. Replacement makes sense when a filling is cracked, leaking, decayed at the edge, or causing symptoms, and the material choice for the new filling is a conversation with your dentist. Appearance alone is a personal decision to weigh against that cost to the tooth.

Can a failing filling be repaired instead of replaced?

Sometimes. A small chip, a rough edge, or early margin damage can in some cases be smoothed, resealed, or patched, keeping the rest of a sound filling in service. Widespread cracks, decay under the filling, or a loose filling usually mean full replacement. Only an examination can say which category yours falls into.

How long does recovery after a filling take?

For most people it is short. Numbness wears off within a few hours, and mild sensitivity to cold or pressure may last a few days, occasionally a few weeks after a deep filling, improving as it goes. Sensitivity that worsens, lingers, or arrives with swelling or a bad taste should be reported to your dentist.

Does a replaced filling last as long as the first one?

Often slightly less, on average, because the cavity is a little larger each time and less natural tooth remains to support the repair. That is a tendency, not a rule: a well placed replacement in a tooth that is otherwise healthy, in a mouth with good habits, can still serve for many years.

Sources & references

• American Dental Association, MouthHealthy. Dental Amalgam. https://www.mouthhealthy.org/all-topics-a-z/dental-amalgam
• Cleveland Clinic. Dental Fillings: Types, Materials and What They Are For. https://my.clevelandclinic.org/health/treatments/17002-dental-fillings
• Gentle Dental. How Long Do Dental Fillings Last: Lifespan by Type (summarizing American Dental Association material guidance). https://www.GentleDental.com/resources/articles/how-long-do-dental-fillings-last
• Mayo Clinic. Cavities and Tooth Decay: Diagnosis and Treatment. https://www.mayoclinic.org/diseases-conditions/cavities/diagnosis-treatment/drc-20352898