Most cavity fillings last somewhere between 7 and 15 years, though the range varies widely depending on the material, the size of the cavity, and where it sits in your mouth. Some fillings hold up for two decades or more, while others need replacement within a few years. The material your dentist uses is only one piece of the puzzle.
Lifespan by Filling Material
The two most common filling materials are composite resin (tooth-colored) and amalgam (silver). For years, the conventional wisdom was that amalgam lasted longer. A 2016 meta-analysis supported that view, finding composites had shorter lifespans and higher rates of new decay forming around them. But a large real-world study published in 2024, drawing on over 600,000 restorations, flipped that narrative. Composite fillings had a failure rate of about 11.9% across all years studied, compared to 17.4% for amalgam. The annual failure rate was roughly 3% for composites and 3.6% for amalgam. At least 60% of composite fillings last beyond 10 years when placed correctly.
These numbers represent averages across all patients and all cavity sizes. A small, single-surface composite filling on a premolar will almost certainly outlast a large, multi-surface filling on a molar. For single-surface fillings specifically, composites showed a failure rate of about 10.8%, while multi-surface fillings climbed to 12% or higher.
Glass ionomer fillings, which release fluoride and are sometimes used for cavities near the gum line or in baby teeth, don’t last nearly as long. In permanent molars, only about half survive to five years, and roughly a third make it to ten. They’re best suited for small, low-stress areas or as temporary solutions. Resin-modified versions perform somewhat better, but they still fall short of composite in durability.
Ceramic and Gold Restorations
If you’re looking for maximum longevity, ceramic inlays and onlays (custom-fitted porcelain pieces) and gold restorations are in a different category. A retrospective study tracking these restorations for over two decades found that ceramic inlays maintained a survival rate of about 92% after 15 years and still held at roughly 92% after 23 years. Gold partial crowns performed similarly, with about 92% surviving past 23 years. Both had annual failure rates below 1%.
The tradeoff is cost and complexity. These restorations require lab fabrication and multiple appointments, and they’re significantly more expensive than standard fillings. When ceramic restorations do fail, it’s usually from fracture. Gold restorations fail more often from complications with the nerve inside the tooth. For large cavities on molars where you want something to last decades, these options are worth discussing with your dentist.
What Shortens a Filling’s Life
The single biggest factor is the size and location of the cavity. Fillings on molars fail more often than those on premolars or front teeth because molars absorb far greater chewing forces. The first molar, the most commonly filled tooth, shows the highest failure rate of any tooth in the mouth. Fillings in the upper jaw also tend to fail slightly more often than those in the lower jaw.
Cavity size matters enormously. Each additional wall of tooth structure that’s missing increases the annual failure rate by 30% to 40%. A filling that spans three surfaces of a tooth (called an MOD restoration, covering the top and both sides) is far more prone to fracture than a simple filling on a single surface. Composite fillings in teeth with fewer than two remaining walls fail 3.3 times more often than those with four walls intact. In practical terms, if your dentist tells you the cavity is large and suggests a crown instead of a filling, that recommendation is backed by solid evidence.
Teeth grinding puts enormous stress on fillings. If you wake up with jaw pain, headaches, or notice your teeth look flattened, you may be grinding at night without realizing it. A custom nightguard acts as a buffer between your upper and lower teeth and can significantly extend the life of your restorations.
Your dentist’s experience also plays a role. Studies comparing operators found that experienced dentists achieve annual failure rates of 1.0% to 1.5%, while less experienced operators see rates of 1.7% to 2.8%. That gap compounds over years.
How Fillings Typically Fail
The two main reasons fillings need replacement are fracture and new decay forming around the edges. Recurrent decay develops when a gap opens between the filling and the tooth, allowing bacteria to slip underneath. This gap can form right away if the bonding wasn’t perfect, or it can develop gradually as the bond breaks down over years of chewing and exposure to saliva. The gum-line edge of fillings between teeth is the most vulnerable spot, regardless of what material was used.
Gaps smaller than about 60 micrometers (thinner than a human hair) generally don’t cause problems. Larger gaps allow enough bacteria through to start demineralizing the tooth underneath. Acidic drinks and sticky foods accelerate this process by weakening enamel and the bonding material at the filling’s margins.
One important nuance: a dark shadow visible on an X-ray beneath an existing filling doesn’t automatically mean the filling has failed. Current understanding of decay recognizes that if the seal around the edges of the filling is intact, bacteria can’t reach whatever is underneath. A well-sealed filling can stay in place even if there’s some older discoloration beneath it. Not every dark spot on an X-ray requires drilling.
Signs Your Filling Needs Replacement
Most failing fillings give you warning signs before they become emergencies:
- Sharp pain or pressure when biting. This often means the filling has cracked, separated from the tooth, or is pressing on the nerve. Biting pain points to structural failure and warrants a prompt visit.
- Lingering sensitivity to hot, cold, or sweet foods. Brief sensitivity is common right after a new filling, but sensitivity that develops months or years later suggests the seal has broken down and irritants are reaching the inner tooth.
- Visible cracks or a loose feeling. If your filling looks fractured or feels rough to your tongue, decay may already be forming underneath, even if nothing hurts yet.
- Dark lines or discoloration at the edges. A shadow around the border of your filling could be surface staining, but it can also signal leakage or decay at the margin.
How to Make Your Fillings Last Longer
The basics matter more than anything fancy. Brushing twice a day with fluoride toothpaste removes the plaque that builds up along filling edges. Flossing daily clears bacteria from between teeth where your brush can’t reach, and those interproximal areas are exactly where fillings are most vulnerable to recurrent decay. An antibacterial mouthwash adds another layer of protection.
Diet plays a real role. Sticky candies can physically pull at fillings, and hard foods like ice or popcorn kernels can crack them. Acidic drinks, including soda and citrus juices, gradually weaken both enamel and the bonding material that holds tooth-colored fillings in place. If you do have acidic food or drinks, rinsing with plain water afterward helps neutralize the acid before it does damage. Chewing sugar-free gum stimulates saliva, which naturally buffers acid and washes away food particles.
Avoid using your teeth as tools. Opening packages, tearing tape, or chewing on pens puts uneven, concentrated force on fillings that they weren’t designed to handle. And if you grind your teeth, a nightguard is one of the single best investments you can make for the longevity of every restoration in your mouth.
Regular dental visits catch small problems early. A filling with a tiny crack or a slight gap at the margin can often be repaired or smoothed before the whole thing needs replacement, saving you time, money, and healthy tooth structure.