Most cavities are treated with a filling, a straightforward procedure that typically takes 20 to 60 minutes in a dentist’s chair. But “cavity treatment” isn’t one-size-fits-all. The right approach depends on how deep the decay has spread, ranging from a simple fluoride application for very early damage all the way to a root canal for decay that has reached the nerve. Here’s what to expect at each stage.
Not Every Cavity Needs a Filling
Tooth decay happens in stages, and catching it early enough can mean avoiding the drill entirely. In the earliest stage, called demineralization, minerals are just starting to leach out of the enamel. You might notice a white spot on the tooth, but no actual hole has formed yet. At this point, the damage can be reversed with fluoride treatments, which help the enamel rebuild itself. Your dentist may apply a concentrated fluoride varnish in the office or recommend a prescription-strength fluoride toothpaste at home.
Once the decay breaks through the enamel surface and creates an actual hole, that’s a true cavity, and it won’t heal on its own. From here, the treatment escalates based on how far the decay has progressed.
What Happens During a Standard Filling
A filling is the most common cavity treatment. The process follows a predictable sequence. First, your dentist numbs the area around the tooth with a local anesthetic, so you shouldn’t feel pain during the procedure. Then, the decayed portion of the tooth is removed using a small drill (called a handpiece) or, in some offices, a laser. An acid gel cleans the prepared area to remove any remaining bacteria or debris.
What happens next depends on the filling material. For tooth-colored composite fillings, the dentist first isolates the tooth to keep it dry, since moisture interferes with bonding. Adhesive layers are applied before the composite material is placed and shaped. A special blue light is used to harden the resin in seconds. Finally, the filling is polished and your bite is checked to make sure the tooth meets the opposing teeth correctly.
The whole appointment is usually done in a single visit. You can eat the same day, though the numbness takes a couple of hours to wear off.
Composite vs. Amalgam Fillings
The two main filling materials are composite resin (tooth-colored) and silver amalgam (metallic). Each has trade-offs worth understanding.
- Composite resin matches your natural tooth color and bonds directly to the tooth structure, which can help reinforce it. The median lifespan is about 11 years. The main downside: composite fillings are more prone to new decay forming around the edges. One study found the risk of this secondary decay was 3.5 times higher with composite than with amalgam. Poor oral hygiene makes this gap worse.
- Silver amalgam is extremely durable, with a median lifespan exceeding 16 years, and it costs less. Its primary failure mode is fracture rather than new decay. The obvious drawback is appearance: it’s silver-colored and visible when you open your mouth. Many dental offices have moved away from amalgam entirely, offering only composite.
A single-surface composite filling typically costs $200 to $400. Amalgam tends to be somewhat less expensive. Your dentist can help you weigh durability against aesthetics based on which tooth is involved.
When a Filling Isn’t Enough
Decay that has spread deeper into the tooth requires more than a simple filling. Tooth structure has layers: the hard outer enamel, a softer layer called dentin underneath, and the pulp (the living tissue with nerves and blood vessels) at the center.
If decay reaches deep into the dentin, a crown may be needed instead of or in addition to a filling. A crown is a cap that covers the entire visible portion of the tooth, protecting what’s left of the structure. Crowns typically cost $500 to $3,000 depending on the material and location of the tooth.
When decay reaches the pulp, you’ll likely need a root canal. This involves removing the infected pulp tissue, cleaning and disinfecting the interior of the tooth, then filling and sealing it. A crown is almost always placed over the tooth afterward to prevent fracture. The signs that decay has reached this stage include spontaneous or lingering pain, especially pain that wakes you up at night or throbs without any trigger. A root canal runs $800 to $1,500, plus the cost of the crown.
Silver Diamine Fluoride: A No-Drill Option
Silver diamine fluoride (SDF) is a liquid applied directly to a cavity to stop decay from progressing, no drilling or numbing required. The American Dental Association recommends it as an option for arresting cavities in both baby teeth and adult teeth, particularly when a patient can’t tolerate a traditional procedure due to age, anxiety, medical conditions, or limited access to dental care.
SDF is applied with a small brush and takes under a minute. For sustained benefit, it needs to be reapplied every six months. The treatment is highly effective at stopping root cavities in older adults, with success rates dramatically higher than placebo. The major cosmetic trade-off is that SDF permanently stains the decayed area black, which makes it a better fit for back teeth or baby teeth that will eventually fall out. It doesn’t restore the tooth’s shape, so a filling or crown may still be needed later for structural reasons.
How Cavities Are Treated in Children
Baby teeth get cavities just like adult teeth, and they still need treatment. Untreated decay in primary teeth can cause pain, infection, and damage to the developing permanent teeth underneath. The treatment approach, however, looks a bit different.
For baby teeth with extensive decay, stainless steel crowns (sometimes called silver caps) are the preferred restoration. According to the American Academy of Pediatric Dentistry, they outlast every other type of restoration for primary teeth. A 2020 study of hundreds of baby molars found that other restorative options resulted in a significant number of teeth needing retreatment, while stainless steel crowns held up. These prefabricated metal caps are fitted over the tooth, cemented in place, and protect the entire remaining structure from further bacterial attack. They’re typically used on back teeth where the metallic appearance is less noticeable, and they fall out naturally when the baby tooth is lost.
When decay in a baby tooth reaches the nerve, a pulpotomy (a partial removal of the pulp) is performed rather than a full root canal. The tooth is then covered with a stainless steel crown to prevent reinfection and fracture.
What Recovery Feels Like
After a standard filling, sensitivity to cold is common for a few days. This is normal and typically resolves on its own. If after one to two weeks your bite still feels “off,” as though the filling is hitting too high, call your dentist. This is a quick fix involving a minor adjustment to the filling surface.
Recovery from a crown or root canal takes a bit longer. You may experience soreness around the treated tooth for several days, and your dentist will provide specific guidance based on the complexity of your procedure. Composite fillings are fully hardened before you leave the office, so there’s no waiting period before you can use the tooth normally, though it’s wise to avoid chewing on the numb side until sensation returns to prevent accidentally biting your cheek or tongue.