A hole in your tooth is a cavity, and it will not heal on its own. Unlike a cut on your skin, tooth enamel cannot regenerate once it’s broken through. The hole will slowly get larger over time, and the options for fixing it become more involved and more expensive the longer you wait. The good news: if you’re noticing it now, you likely still have straightforward, affordable options.
What That Hole Actually Is
Your teeth have three layers. The outer shell is enamel, the hardest tissue in your body. Beneath that is dentin, a softer, yellowish layer. At the center is the pulp, which contains the nerves and blood vessels that keep the tooth alive.
A cavity starts when bacteria in your mouth feed on sugars and produce acid. That acid dissolves minerals from your enamel, first creating a white or brown spot on the surface. If nothing changes, the enamel breaks down enough to form a physical hole. At this point, you’ve moved past the earliest stage of decay into a true cavity that needs treatment.
Once the hole reaches dentin, things speed up. Dentin is softer than enamel and breaks down faster. Research in pediatric teeth found it takes roughly 10 months for decay to work through the enamel layer, then another 17 months to reach deep into the dentin. Adult enamel is thicker, so the timeline can be longer, but the direction only goes one way. Decay doesn’t pause or reverse once a hole has formed.
How to Tell How Deep It Is
The symptoms you’re experiencing give a rough indication of how far the hole has progressed, even before a dentist takes an X-ray.
If you can see a small hole but have no pain, the decay is likely still in the enamel or just barely into the dentin. You might notice food getting stuck in the spot, or a rough edge your tongue keeps finding. This is the ideal time to get it treated.
If you feel a sharp zing when eating something cold or sweet, but it disappears within a few seconds, the decay has reached the dentin but the nerve is still healthy. This is called reversible sensitivity, meaning the nerve is irritated but recoverable. A filling can still solve the problem.
If sensitivity to hot or cold lingers for more than a few seconds, or if you get spontaneous aching or throbbing that wakes you up at night, the nerve inside the tooth is likely damaged beyond recovery. Heat sensitivity that lingers is a particularly telling sign. At this stage, a simple filling won’t be enough.
What a Dentist Will Do
Treatment depends entirely on depth. For a cavity contained within the enamel or outer dentin, the standard fix is a filling. The dentist removes the decayed material, then fills the space with a tooth-colored composite resin. The whole process typically takes 30 to 60 minutes, and you can eat normally the same day. A composite filling runs roughly $90 to $250 per tooth without insurance.
If the hole is large enough that there isn’t much healthy tooth structure left to support a filling, you’ll need a crown instead. This is a cap that fits over the entire visible portion of the tooth. Crowns cost between $800 and $2,000 per tooth, and require two visits in most offices (one to prepare the tooth and take impressions, another to cement the final crown).
When decay has reached the pulp and the nerve is damaged, the tooth needs a root canal before it can be restored. During this procedure, the infected pulp is removed, the inner canals are cleaned and sealed, and then a crown is placed on top. It sounds intimidating, but modern root canals are comparable to getting a filling in terms of discomfort. The bigger difference is cost and time, since you’re paying for the root canal procedure plus the crown.
A No-Drill Option for Some Cavities
If you’re anxious about dental work or can’t get into a chair right away, there’s an interim option worth knowing about. Silver diamine fluoride (SDF) is a liquid that a dentist paints directly onto a cavity. It kills the bacteria causing the decay and hardens the affected tooth surface, effectively stopping the cavity from growing. It’s been shown to be as effective at halting decay progression as traditional drilling-and-filling approaches, and the application takes less than a minute with no numbing needed.
The catch: SDF turns the decayed area permanently black. On a back molar you don’t see when you smile, that may not matter. On a front tooth, it’s a dealbreaker for most people. It also doesn’t restore the lost tooth structure, so you’ll still eventually want a filling or crown. But it buys you time and prevents the situation from getting worse while you arrange treatment.
What Happens If You Ignore It
Leaving a hole untreated doesn’t just mean a bigger dental bill later. Once bacteria reach the pulp, infection can spread beyond the tooth itself. The most common result is a dental abscess: a pocket of pus that forms at the root tip, causing intense, constant pain and sometimes visible swelling in the gum or cheek.
A tooth that could have been saved with a $150 filling may eventually need extraction and replacement with an implant, which can cost several thousand dollars. Beyond the financial hit, there are real health risks. Dental infections can spread into the jaw, throat, and neck. In rare but serious cases, the infection enters the bloodstream. Chronic oral infections have also been linked to cardiovascular disease and respiratory problems.
Signs You Need Emergency Care
Most cavities are not emergencies. They progress over months, and scheduling a dental appointment within a few weeks is perfectly reasonable. But certain symptoms mean the situation has become urgent:
- Facial swelling that is visible from the outside, especially if it’s spreading or getting worse
- Fever along with tooth pain, which signals the infection is affecting your body systemically
- Difficulty breathing or swallowing, which can indicate the infection has spread into your throat or airway
If you have a fever and facial swelling and can’t reach a dentist, go to an emergency room. A dental abscess that spreads into the neck or chest can become life-threatening, and antibiotics need to be started quickly. For everything short of those red flags, call your dentist’s office, describe what you’re feeling, and they’ll tell you how soon you need to come in.
What to Do Right Now
If you’ve just noticed a hole, the single most useful thing you can do is book a dental appointment. In the meantime, keep the area clean by gently brushing around it and rinsing with warm salt water after meals. Avoid chewing directly on that tooth, especially anything hard or sticky that could break off more of the weakened structure. Over-the-counter pain relievers can manage any sensitivity until your appointment.
The size of the hole you can see doesn’t always reflect what’s happening underneath. Decay often spreads wider beneath the enamel surface, like an iceberg. An X-ray is the only way to know the true extent, which is why getting it checked matters more than trying to judge severity on your own.