Once a cavity has formed a physical hole in your tooth, there is no way to reverse it at home. You need a dentist to remove the decay and restore the tooth. However, if the decay is still in its earliest stage, before a hole has formed, you can sometimes reverse it through remineralization. The path forward depends entirely on how far the damage has progressed.
Early Decay Can Be Reversed
Tooth decay doesn’t start as a hole. It starts as a loss of minerals from the enamel surface, often visible as a white, brown, or black spot on the tooth. At this stage, there are usually no symptoms at all. The good news: this early damage can be repaired without a filling.
Your enamel is made of a mineral crystal built from calcium and phosphate. When bacteria in your mouth feed on sugars, they produce acid. Once the acid drops the pH in your mouth below about 5.5, those minerals start dissolving out of the enamel. This is demineralization. But when the acid clears and your saliva brings the pH back to normal, calcium and phosphate from saliva recrystallize back into the enamel. That’s remineralization, and it happens naturally throughout the day.
Fluoride supercharges this process. When fluoride is present during remineralization, it replaces part of the original mineral structure with a harder, more acid-resistant version. A remineralized spot that incorporates fluoride actually becomes more resistant to future decay than the original enamel was. This is why fluoride toothpaste, fluoride rinses, and professional fluoride treatments are the most effective tools for reversing early-stage decay.
To tip the balance toward remineralization, you need to reduce how often acid attacks happen and give your saliva time to do its repair work. That means limiting sugary and acidic snacks between meals, brushing twice daily with fluoride toothpaste, and drinking water throughout the day. Xylitol, a sugar substitute found in certain gums and mints, also helps by creating a less acidic environment in the mouth. Most clinical trials have used 2 to 14 grams per day, chewed or dissolved four to five times daily, to see meaningful effects on decay-causing bacteria.
What Happens When a Cavity Forms
If demineralization continues unchecked, the enamel surface eventually breaks down into an actual hole. Once that happens, remineralization can’t rebuild the lost structure. The cavity will only get larger over time as bacteria colonize the space and continue producing acid deeper into the tooth.
As the decay moves past the enamel into the softer layer underneath (dentin), you’ll typically start noticing symptoms: sensitivity to sweets, hot drinks, or cold foods. You might feel a sharp twinge when biting down. If decay reaches the innermost part of the tooth where the nerve lives, the pain becomes more persistent and intense. Left long enough, the tooth can develop an infection or abscess, which causes throbbing pain, facial swelling, and sometimes fever.
Fillings: The Standard Fix
For most cavities, a filling is all you need. The dentist removes the decayed portion of the tooth and fills the space with a restorative material. The two most common options are composite resin (tooth-colored) and amalgam (silver-colored).
Composite resin is now used in the vast majority of cases. In a large study of over 668,000 restorations on back teeth, about 83% were composite. Composite fillings also performed slightly better over time, with a failure rate of roughly 12% compared to 17% for amalgam. For single-surface cavities, composite fillings failed about 11% of the time versus 14% for amalgam.
Cost depends on size. A small, single-surface composite filling typically runs $90 to $150 without insurance. A cavity that spans two surfaces costs $130 to $220, and a large cavity covering three or more surfaces runs $180 to $300. Amalgam is cheaper, starting around $50 for a small filling, but many dental offices have moved away from it.
When a Filling Isn’t Enough
If too much tooth structure has been lost, a filling alone won’t hold. Dentists typically recommend a crown when the tooth has a large existing filling, severe decay, visible cracks, or significant erosion. A crown caps the entire visible portion of the tooth, restoring its shape and strength. Porcelain crowns range widely in cost, from $250 to $4,500 depending on the material and location.
When decay reaches the nerve, the tooth needs either a root canal or extraction. A root canal removes the infected nerve tissue, cleans the internal canals, and seals the tooth. It saves the natural tooth, and most people keep a root canal-treated tooth for many years afterward. Extraction is the alternative when the damage is too extensive to save the tooth, and the gap is then replaced with an implant, bridge, or partial denture.
Silver Diamine Fluoride: A Non-Drill Option
For people who can’t tolerate a traditional filling, whether due to age, anxiety, or medical conditions, silver diamine fluoride (SDF) offers another path. It’s a liquid painted directly onto the cavity that kills bacteria and hardens the decayed surface, effectively stopping the cavity from growing. It doesn’t restore the tooth’s shape like a filling does, but it arrests the decay in place. For root cavities in adults, SDF prevented new decay at rates 72% higher than a placebo, and it successfully stopped existing root decay at even higher rates. The main drawback: it permanently stains the decayed area black, which makes it less popular for visible front teeth.
Home Remedies That Don’t Work
If you’ve seen claims that oil pulling, charcoal, or herbal rinses can heal a cavity, the evidence doesn’t support them. The American Dental Association has stated plainly that there are no reliable scientific studies showing oil pulling reduces cavities, whitens teeth, or improves oral health. Once a physical hole exists in the tooth, no rinse, paste, or supplement can regrow that lost enamel. Delaying professional treatment while trying home remedies gives the decay more time to spread deeper, which turns a simple filling into a crown or root canal.
Keeping New Cavities From Forming
After getting a cavity treated, the goal shifts to preventing the next one. The same acid cycle that caused the first cavity is still happening in your mouth every time you eat. Brushing with fluoride toothpaste twice a day is the single most effective habit, because it delivers fluoride directly to the enamel surface during the remineralization window. Flossing clears bacteria from between teeth where your brush can’t reach, which is exactly where many cavities start.
What you eat matters as much as how you clean. Frequent snacking, especially on sticky or sugary foods, keeps the pH in your mouth low for extended periods, giving acid more time to dissolve enamel. Three meals with limited snacking in between gives your saliva enough time to neutralize acid and repair minor damage before it becomes permanent. Chewing xylitol gum after meals can help speed that recovery by stimulating saliva flow while creating conditions that are hostile to decay-causing bacteria.
Regular dental checkups catch new decay in the white-spot stage, when remineralization is still an option. X-rays reveal decay forming between teeth long before you’d feel any pain. The earlier a cavity is found, the smaller the filling, the lower the cost, and the more tooth structure you keep.