Most dental fillings don’t need to be replaced on a fixed schedule. Instead, they’re replaced when they show signs of wear, damage, or decay underneath. That said, every filling has a finite lifespan, and knowing the typical range for your type of filling helps you understand what to expect. Composite (tooth-colored) fillings last about 7 years on average, amalgam (silver) fillings last around 15 years, and gold fillings can go 20 years or more.
How Long Each Filling Material Lasts
The material your dentist used plays the biggest role in how long your filling will hold up. Here’s what the averages look like:
- Composite resin (tooth-colored): about 7 years on average. These are the most common fillings placed today, but they wear faster under heavy bite forces, particularly on molars.
- Amalgam (silver): about 15 years. Amalgam handles heavy chewing loads better than composite, especially in large restorations on back teeth.
- Ceramic: about 15 years. These are more stain-resistant than composite and hold up well over time.
- Gold: 20 years or more, according to the American Dental Association. Gold is the most durable option, and fillings lasting 30+ years aren’t unusual.
These are averages, not deadlines. A well-placed composite filling in a low-stress area of the mouth can last well beyond 7 years, while the same material on a molar in someone who grinds their teeth might fail in 3 or 4. A randomized clinical trial that tracked nearly 1,750 fillings over seven years found a survival rate of 94.4% for amalgam and 85.5% for composite, with annual failure rates for composites ranging as high as 9.4% in some cases.
Why Fillings Eventually Fail
The overwhelming reason fillings need replacing is new decay forming around or beneath the existing restoration. One observational assessment found that secondary decay accounted for over 93% of failed composite cases and over 95% of failed amalgam cases. This happens when tiny gaps develop between the filling and your tooth, letting bacteria and acids seep underneath where your toothbrush can’t reach.
Those gaps form through several mechanisms. Composite fillings shrink slightly as they harden during placement, which can create microscopic spaces at the edges. Over years of chewing, thermal changes from hot and cold food, and general wear, those gaps gradually widen. Amalgam fillings corrode slowly over time, which can actually help seal margins initially but eventually contributes to breakdown.
Mechanical stress is the other major factor. Every time you chew, your fillings absorb force. On molars, those forces are substantial, and over thousands of meals, fillings chip, crack, or wear down. Composites lose material more readily under high pressure than amalgam or gold, which is why material choice matters more for back teeth than front teeth.
Habits That Shorten Filling Lifespan
Teeth grinding (bruxism) is one of the biggest threats to any restoration. The repeated clenching and lateral forces crack fillings, wear down their surfaces, and break the seal at the edges. If you grind your teeth, a custom night guard can significantly extend the life of your fillings by absorbing those forces overnight, when most grinding happens.
Diet and lifestyle matter too. Heavy alcohol use can double early failure rates within the first two years, according to a study published in Frontiers in Medicine. Smoking has been linked to higher failure rates in composite fillings, particularly on front teeth. Chewing ice, biting pen caps, or regularly eating very hard foods all accelerate wear. Poor oral hygiene speeds up the secondary decay that causes most failures, since more bacteria at the filling margins means faster breakdown of the seal.
Signs a Filling Needs Replacing
Rather than counting years, pay attention to what your fillings are telling you. These are the signals that something has changed:
- Pain when chewing or biting: this can mean the filling has cracked, pulled away from the tooth, or is pressing against a nerve.
- Lingering sensitivity: if cold, hot, or sweet drinks trigger sensitivity that doesn’t fade quickly, the seal around your filling may have broken down, allowing irritants to reach the inner tooth.
- Visible damage: a filling that looks rough, fractured, or chipped can harbor decay underneath, even if it doesn’t hurt yet.
- Dark lines at the edges: a shadow or dark border around a filling could be surface staining, but it can also signal decay or leakage beneath the restoration.
- A filling that feels loose or “off”: even after trauma that leaves a filling looking intact, tiny cracks may have formed that let bacteria in.
Your dentist checks for these signs at routine visits, often catching problems before you feel them. X-rays can reveal decay forming under a filling that looks perfectly fine on the surface. This is one of the practical reasons regular checkups matter: catching a failing filling early usually means a simpler, smaller replacement.
Why You Shouldn’t Replace Fillings Prematurely
Every time a filling is removed and replaced, some additional healthy tooth structure comes off with it. The cavity gets slightly larger, the walls of the tooth get slightly thinner, and the tooth becomes a little weaker. After multiple replacement cycles, a tooth may no longer have enough structure to support a filling at all and will need a crown instead.
This is why dentists generally don’t recommend replacing a filling just because it’s reached some age threshold. A 20-year-old amalgam filling with intact margins and no signs of decay underneath is better left alone than swapped out for something new. The goal is to preserve as much natural tooth as possible over your lifetime, and that means replacing fillings only when there’s an actual clinical reason to do so.
How to Make Your Fillings Last Longer
The same habits that protect your natural teeth protect your fillings. Brushing twice a day and flossing daily reduces the bacterial load around filling margins, slowing the development of secondary decay. Fluoride toothpaste helps strengthen the enamel surrounding your restorations.
If you grind your teeth, getting a custom night guard is one of the highest-impact things you can do for the longevity of your dental work. Limiting very hard or sticky foods reduces mechanical stress on fillings, especially composites on back teeth. And keeping up with dental visits every six months (or whatever interval your dentist recommends) lets problems get caught while they’re still small, often meaning a simple filling replacement rather than a crown or more involved procedure.