A hole in your tooth is a cavity, and it will keep getting bigger if left alone. Unlike a cut on your skin, tooth enamel can’t heal itself once a physical hole has formed. The decay that created the hole continues eating through deeper layers of the tooth, eventually reaching the nerve, and each stage brings more pain and more expensive treatment.
How the Hole Got There
Bacteria in your mouth feed on sugars and starches from the food you eat. As they digest those carbohydrates, they produce lactic acid. That acid dissolves the minerals in your tooth enamel, which is the hard outer shell. Enamel is the hardest tissue in your body, but it’s not immune to sustained acid attacks.
The process starts with demineralization: a white spot appears on the tooth where minerals are being leached away. At this early stage, the damage can actually be reversed with fluoride and better hygiene. But once enough mineral is lost that the surface physically breaks down, you have a hole. That hole is permanent, and it traps food and bacteria in a place your toothbrush can’t reach, which accelerates the damage.
What You Might Be Feeling Right Now
The symptoms you experience depend on how deep the hole goes. A shallow cavity that’s only in the enamel often causes no pain at all. You might not even know it’s there unless you see a dark spot or your dentist catches it on an X-ray.
Once the decay reaches the dentin, the softer layer beneath the enamel, things change. Dentin contains tiny tubes that connect to the tooth’s nerve, so you’ll likely start noticing sensitivity to hot, cold, or sweet foods and drinks. This can range from a brief zing to a lingering ache. You may also feel a sharp edge or gap when you run your tongue over the tooth, or notice food getting stuck in the same spot repeatedly. Pain when you bite down is another common sign that the hole has reached a meaningful depth.
What Happens If You Leave It
Tooth decay moves through your tooth in predictable stages, and each one is harder to treat than the last.
After breaking through the enamel, decay accelerates. Dentin is softer and more porous, so the acid from bacteria chews through it faster than it did through the enamel. The hole widens internally, sometimes creating a situation where a small opening on the surface hides a much larger cavity underneath.
The next layer is the pulp, the innermost part of the tooth that contains nerves and blood vessels. When bacteria reach the pulp, you’ll know it. The pulp becomes inflamed and swells, but because it’s trapped inside a rigid tooth, the pressure builds with nowhere to go. This produces intense, throbbing pain that can wake you up at night, sometimes radiating into your jaw, ear, or temple. At this point, a simple filling won’t fix the problem.
If the infection continues unchecked, the pulp tissue dies and bacteria can spread beyond the tooth into the surrounding bone and gum tissue, forming an abscess. An abscess is a pocket of pus that causes swelling, a persistent bad taste in your mouth, and sometimes a visible bump on the gum near the affected tooth.
When It Becomes Dangerous
Most cavities are not emergencies, but an untreated abscess can become one. The infection can spread from the tooth into the jaw, the spaces under the tongue, or the throat. If swelling pushes into the throat area, it can make it difficult to breathe or swallow. A tooth located near the sinuses (typically upper back teeth) can create an opening between the abscess and the sinus cavity, causing a sinus infection that won’t respond to typical treatment.
In rare but serious cases, the bacteria enter the bloodstream and cause sepsis, a body-wide infection that requires emergency care. People with weakened immune systems face a higher risk of these spreading infections. If you develop a fever along with facial swelling, or have trouble breathing or swallowing, that warrants an emergency room visit rather than waiting for a dental appointment.
How Each Stage Is Treated
The earlier the hole is caught, the simpler and cheaper the fix.
- Small cavity (enamel or shallow dentin): A standard filling. The dentist removes the decayed material and fills the space with a composite resin or similar material. This is a single appointment, usually under an hour. Composite fillings typically cost $200 to $400 per surface.
- Large cavity (deep dentin): If the hole has undermined enough of the tooth structure, a filling alone won’t hold. You’ll need a crown, which is a cap that covers the entire visible portion of the tooth. Crowns run $500 to $3,000 depending on the material and location.
- Pulp involvement: Once infection reaches the nerve, the treatment is a root canal. The infected pulp is removed, the interior of the tooth is cleaned and sealed, and a crown is placed on top. This typically requires two appointments.
- Severe infection or structural loss: If the tooth is too damaged to save, extraction is the remaining option. After extraction, you may want to consider a replacement (implant or bridge) to prevent the consequences of a missing tooth.
What Losing a Tooth Does to Your Jaw
If the hole progresses far enough that the tooth needs to be pulled, the consequences extend beyond the gap in your smile. Your jawbone stays dense and healthy partly because of the stimulation it receives from the roots of your teeth during chewing. When a tooth is removed, that section of jawbone stops receiving those signals. The bone-destroying cells in your body continue breaking down bone in the area, while bone-building cells slow their activity there. The result is gradual bone loss in the jaw at the extraction site.
This bone loss can cause neighboring teeth to shift, change your bite alignment, and alter the shape of your face over time, particularly if multiple teeth are lost. It also makes placing a dental implant later more complicated, since implants need a certain amount of bone to anchor into.
Slowing Down an Existing Cavity
You can’t reverse a hole that’s already formed, but you can slow the decay while you arrange treatment. Brush with fluoride toothpaste twice a day, paying attention to the area around the cavity. Rinse with a fluoride mouthwash. Cut back on sugary and acidic foods and drinks, since these fuel the bacteria producing the acid that’s enlarging the hole. Avoid chewing on the side of the affected tooth to reduce the risk of cracking weakened enamel.
These measures buy time, but they don’t replace treatment. The hole is a physical defect in a structure that can’t regrow, and bacteria will continue to colonize it regardless of how well you brush. The earlier you get it filled, the less invasive and less expensive the fix will be.