How a cavity gets treated depends entirely on how far the decay has progressed. A very early cavity, one that hasn’t yet broken through the enamel surface, can actually be reversed without any drilling at all. Once decay creates a permanent hole in the tooth, though, a dentist needs to physically repair it with a filling, crown, or more involved procedure. Here’s what each stage looks like and what to expect.
Early Decay Can Be Reversed
Before a cavity becomes a cavity, there’s a stage where the enamel is losing minerals but hasn’t yet developed a hole. You might notice faint white spots on the tooth surface. At this point, the damage is reversible. Your enamel can actually rebuild itself using minerals from saliva and fluoride from toothpaste or professional treatments.
A dentist who spots early demineralization will typically apply a fluoride varnish or gel directly to the affected teeth. For people at higher risk of decay, prescription-strength fluoride toothpaste (5,000 ppm, compared to the standard 1,000 to 1,500 ppm in over-the-counter brands) can make a significant difference. In clinical trials, people using prescription-strength fluoride had roughly half the active decay lesions compared to those using regular toothpaste, and far more of their existing early lesions hardened and arrested on their own.
Dental sealants, thin plastic coatings painted onto the chewing surfaces of back teeth, are another option for preventing decay from taking hold in the grooves where food and bacteria collect most easily. These are especially common for children and teenagers but can benefit adults with deep grooves in their molars.
Standard Fillings for Most Cavities
Once decay breaks through the enamel and creates a permanent hole, no amount of fluoride will fix it. A dentist removes the decayed material, cleans the area, and fills the space with a restorative material. The two most common options are composite resin and silver amalgam, and they differ in meaningful ways.
Composite resin fillings are tooth-colored, blending in with the surrounding enamel. They’re the go-to choice for visible teeth and smaller cavities. On average, they last about 5 to 7 years with good care, though many last longer. They cost between $90 and $300 nationally, depending on how many surfaces of the tooth are involved. A small, single-surface filling runs $90 to $150, while a larger cavity spanning three or more surfaces pushes the price toward $180 to $300.
Silver amalgam fillings are made from a mix of metals including mercury, silver, and tin. They’re noticeably darker than the surrounding tooth, so they’re less popular for front teeth, but they’re exceptionally durable. Amalgam fillings typically last 10 to 15 years, sometimes longer, making them a practical choice for molars that absorb heavy chewing forces. They’re also cheaper, ranging from $50 to $200.
Crowns for Larger Areas of Decay
When a cavity is large enough that removing the decayed material would compromise the structural integrity of the tooth, a standard filling won’t hold up. In these cases, a dentist will recommend a crown instead. A crown is a custom-made cap that fits over the entire visible portion of the tooth, restoring its shape, strength, and function. Think of it as the difference between patching a small hole in a wall versus replacing a whole section: at some point, the patch won’t hold.
Getting a crown usually takes two visits. During the first, the dentist shapes the remaining tooth structure and takes impressions or digital scans. You’ll wear a temporary crown for a week or two while the permanent one is fabricated. The second visit is for fitting and cementing the final crown. Porcelain crowns, which match natural tooth color, range from $250 on the low end to several thousand dollars depending on the material and complexity.
Root Canals for Deep Infections
If decay reaches the pulp, the soft tissue inside the tooth containing nerves and blood vessels, the tooth becomes infected. This is the stage that usually brings intense, throbbing pain. At this point, you have two realistic options: a root canal or an extraction.
A root canal involves removing the diseased pulp from inside the tooth, cleaning and disinfecting the inner chambers, then filling and sealing them. The tooth stays in your mouth and is typically topped with a crown afterward for protection. The procedure itself is done under local anesthesia and, despite its reputation, feels similar to getting a deep filling.
Extraction is the alternative when the tooth is too damaged to save. After pulling the tooth, you’d eventually need a replacement (an implant or bridge) to prevent the surrounding teeth from shifting and to restore your ability to chew properly.
Silver Diamine Fluoride: A Non-Drill Option
Silver diamine fluoride (SDF) is a liquid that a dentist paints onto a cavity to stop decay from progressing. It doesn’t remove the damaged part of the tooth or restore its shape, but it effectively kills bacteria and hardens the remaining tooth structure. For preventing and arresting root cavities in adults, SDF has shown success rates 72% to over 700% higher than placebo treatments, according to a review cited by the American Dental Association.
The major trade-off is cosmetic. SDF permanently stains the treated area black. It can also leave an unpleasant metallic taste and occasionally irritate the gums. For cavities on back teeth or in patients who can’t tolerate traditional dental procedures (young children, elderly patients, people with severe dental anxiety), it’s a practical way to halt decay without drilling. It’s not a replacement for a filling, but it can buy time or serve as a long-term solution when a filling isn’t feasible.
Why DIY Kits Are Risky
Over-the-counter temporary filling kits are sold for emergency use, but treating an actual cavity at home creates several problems. These materials can’t bond to your tooth the way professional composite resin does. They’re held in place only by friction, making them prone to falling out or breaking under normal chewing. Worse, pushing temporary filling material into a decayed hole without removing the bacteria underneath traps the infection inside, which can accelerate the decay and lead to a root canal or tooth loss.
A poorly shaped home filling can also throw off your bite. Teeth that don’t meet correctly cause jaw pain, headaches, and can crack or chip neighboring teeth over time. And if the cavity was caused by an underlying issue like gum disease or widespread decay on other teeth, skipping the dentist means those problems continue unchecked.
What to Expect After a Filling
Some sensitivity after getting a filling is completely normal. General discomfort usually fades within a day or two. Sensitivity to hot, cold, sweet foods, or pressure from chewing can linger for one to two weeks as the tooth adjusts. During this time, you might find it more comfortable to chew on the opposite side and avoid extremely hot or cold drinks.
If pain persists beyond a week, or if biting down on the filled tooth causes a sharp jolt, the filling may be sitting too high and needs a quick adjustment. This is a simple fix: the dentist shaves down the filling slightly so your bite meets evenly again. Ongoing sensitivity beyond two weeks, or pain that gets worse rather than better, warrants a follow-up visit to rule out deeper issues.
Preventing the Next Cavity
The same process that caused your first cavity is still at work in your mouth. Every time you eat or drink something sugary or starchy, bacteria on your teeth produce acids that pull minerals out of the enamel. Fluoride toothpaste helps push minerals back in, but the balance tips toward decay when acid attacks are frequent or oral hygiene is inconsistent.
Brushing twice a day with fluoride toothpaste, flossing daily, and limiting how often you snack on sugary or acidic foods are the foundation. Regular dental cleanings remove hardened plaque (tarite) that you can’t remove at home, and they give your dentist a chance to catch new decay at the white-spot stage, when it’s still reversible. If you’re someone who gets cavities frequently, ask about prescription-strength fluoride toothpaste or additional sealants on vulnerable teeth.