Fixing a cavity depends on how far the decay has progressed. Small cavities caught early can sometimes be reversed without any drilling at all, while moderate cavities need a filling, and deep decay may require a crown or root canal. Most people will need a standard filling, which takes about 20 to 60 minutes in the dentist’s chair and costs anywhere from $50 to $300 depending on the material used.
Very Early Cavities Can Be Reversed
Before a cavity becomes a full hole in your tooth, it starts as a weakened spot on the enamel where minerals have been lost. At this stage, the damage is reversible through a process called remineralization. Your saliva naturally deposits calcium and phosphate back into weakened enamel, and fluoride accelerates that repair. Under healthy conditions, fluoride and saliva are often enough to remineralize these early lesions on their own.
You can support this process by using fluoride toothpaste, drinking fluoridated water, and adding a calcium-phosphate rinse or gel to your routine. These products supply the raw materials your enamel needs to rebuild. Your dentist may also apply a concentrated fluoride varnish directly to the weak spot. The catch: this only works on incipient lesions, meaning the decay hasn’t broken through the enamel surface yet. Once there’s an actual hole, remineralization can’t close it, and you’ll need a filling.
What Happens During a Filling
A filling is the most common cavity fix. The procedure is straightforward. Your dentist numbs the tooth with a local anesthetic, then uses specialized instruments to remove all the decayed tissue. The cleaned-out space is filled with a restorative material, shaped to match your tooth’s natural contours, polished smooth, and checked to make sure your bite feels normal. For tooth-colored composite fillings, a curing light is used to harden the material in layers.
If the idea of a drill makes you anxious, some dental offices now use lasers to remove decay instead. Research from UC San Francisco has shown that today’s dental lasers can safely and painlessly remove cavities, making them especially appealing for children or anyone nervous about traditional drills. Laser treatment isn’t available everywhere and may cost more, but it’s worth asking about if dental anxiety is a barrier for you.
For sedation, most fillings only require a local numbing injection. If you have significant anxiety, many offices offer nitrous oxide (laughing gas) or mild oral sedation to help you relax during the procedure.
Choosing a Filling Material
The two main options are amalgam (silver-colored) and composite resin (tooth-colored). Amalgam fillings run about $50 to $200, while composite fillings cost $90 to $300. Insurance typically covers both, though your out-of-pocket amount varies by plan.
Composite resin has become the more popular choice, and the data supports it. A large study analyzing over 668,000 fillings found that composite restorations had a lower failure rate than amalgam across the board. About 11.9% of composite fillings failed over the study period, compared to 17.4% of amalgam fillings. For single-surface cavities (the most common type), composite failed 10.75% of the time versus 14.01% for amalgam. The gap narrowed for very large fillings covering four or five surfaces, where both materials performed similarly.
Composite does have downsides. It can stain over time from coffee, tea, and red wine. Amalgam, meanwhile, is being phased out globally due to its mercury content, even though it has a long safety record. For most people getting a filling today, composite resin is the default recommendation.
When a Filling Isn’t Enough
If decay has destroyed a large portion of the tooth, a simple filling won’t hold. When a tooth is more filling than natural structure, it becomes fragile and prone to cracking. In these cases, a crown (a cap that fits over the entire visible tooth) provides the structural support the tooth needs.
If the decay has reached the nerve inside the tooth, you’ll likely need a root canal before a crown is placed. Signs that decay has gone this deep include a severe toothache while chewing, lingering sensitivity to hot or cold that doesn’t fade after a few seconds, swelling in the gums or jaw, or a small bump on the gum near the tooth (an abscess). During a root canal, the infected nerve tissue is removed, the inside of the tooth is cleaned and sealed, and a crown is placed on top to protect what remains.
Your dentist determines which treatment you need based on X-rays and vitality testing, which checks whether the nerve is still alive, inflamed, or infected. They’ll also consider how much healthy tooth structure is left, where the tooth sits in your mouth (back teeth handle more grinding force), and your bite alignment.
Recovery After a Filling
Most people experience minor pain and sensitivity for the first few days after a filling. This is normal and typically resolves within a week. While the numbness wears off (usually one to three hours), avoid eating so you don’t accidentally bite your cheek or tongue.
Once sensation returns, stick to soft foods for a couple of days: soup, yogurt, soft pasta, smoothies, and similar options. When you do eat solid foods, chew on the opposite side of your mouth from the filling. Avoid very hot or cold foods and anything chewy like caramels or gum, which can pull on a fresh filling before it’s fully settled.
If sensitivity persists beyond a week, or if your bite feels off when you close your mouth, call your dentist. A filling that sits even slightly too high can cause discomfort, and it takes just a few minutes to adjust.
How Long Fillings Last
No filling lasts forever. Based on large-scale failure data, composite fillings fail at a rate of roughly 3% per year and amalgam at about 3.5% per year. In practical terms, most fillings last somewhere between 7 and 15 years before they need replacement, depending on the size of the filling, where it is in your mouth, and how well you maintain your oral hygiene.
Larger fillings fail sooner than smaller ones. A single-surface composite filling has about a 10.75% chance of failing over the study period, while one covering four or five surfaces jumps to nearly 18%. This is one reason dentists push for catching cavities early: a small filling lasts longer, costs less, and preserves more of your natural tooth.