A root canal removes infected tissue from inside a tooth, then fills and seals the empty space to save the tooth from extraction. The procedure typically takes one or two appointments, each lasting 30 to 90 minutes depending on the tooth’s complexity. Here’s what actually happens at each stage, from numbing to recovery.
Why a Root Canal Becomes Necessary
Every tooth has soft tissue called pulp running through its center and down into the roots. This pulp contains nerves, blood vessels, and connective tissue. When bacteria reach the pulp, usually through a deep cavity or a crack in the tooth, the tissue becomes inflamed. This condition is called pulpitis.
In early stages, the inflammation can sometimes reverse on its own once the source of irritation is removed. But once the damage progresses far enough, the pulp can’t heal. The tissue eventually dies, and without treatment, infection can spread to the bone surrounding the root tip. At that point, the only two options are a root canal or pulling the tooth entirely.
Getting Numb: How Pain Is Managed
The procedure starts with a local anesthetic, the same type of injection used for fillings. The most common numbing agents are lidocaine and articaine, both of which block nerve signals so you feel pressure but not pain.
One thing worth knowing: teeth that are already infected and painful can be harder to numb. Inflamed pulp tissue changes the way nerves respond to anesthesia, lowering their threshold for firing pain signals. If the first injection doesn’t fully take, your dentist or endodontist has several backup options. These include additional injections closer to the tooth, injections directly into the ligament surrounding the root, or in some cases a nasal spray anesthetic approved for dental use. The goal is always complete numbness before any work begins.
Step by Step: What Happens During the Procedure
Once you’re numb, a small rubber sheet called a dental dam is placed over the area. It clips around the tooth being treated, isolating it from the rest of your mouth. This keeps saliva and bacteria out of the work area and gives the dentist a clean, dry field to operate in.
Next comes the access opening. The dentist drills a small hole through the top (or back) of the tooth to reach the pulp chamber inside. Using tiny, flexible instruments thinner than a sewing needle, they remove the inflamed or dead pulp tissue from the chamber and from each root canal. A single front tooth has one canal. Molars typically have three or four, sometimes more.
After the tissue is removed, the canals are shaped and cleaned. The dentist uses progressively larger files to widen each canal slightly, creating a smooth, tapered channel. Throughout this process, the canals are flushed with an antimicrobial solution to kill remaining bacteria and wash out debris. Some offices use 3D imaging (cone-beam CT scans) before or during the procedure to map complex canal anatomy that standard X-rays can miss, including hidden extra canals, unusual curves, or tiny fractures.
Once the canals are clean and dry, they’re filled with a rubber-like material called gutta-percha. This material is inert, dimensionally stable, and causes virtually no allergic reactions or inflammatory response in the body. It’s paired with a sealer that cements it to the canal walls and fills microscopic gaps. Some sealers chemically bond to the inner tooth structure, which can improve the seal and even add a small amount of strength to the root. The gutta-percha can be softened with heat and compressed to conform tightly to the canal’s shape, ensuring a dense fill with no voids where bacteria could regrow.
Finally, a temporary or permanent filling closes the access hole. In straightforward cases, everything happens in a single visit. More complex infections, especially those involving multiple canals or significant swelling, may require two visits with medication placed inside the tooth between appointments.
What Recovery Feels Like
Most people feel some tenderness or sensitivity for a few days afterward. This is a normal response to the cleaning and shaping process, not a sign that something went wrong. The discomfort is generally mild enough to manage with over-the-counter pain relievers like ibuprofen. Following the dosing instructions on the packaging is usually sufficient, and most people return to normal activities the next day.
If pain increases rather than decreasing after the first two or three days, or if you develop significant swelling, that’s worth a call to your dentist. These signs can indicate a complication that needs attention.
Why You’ll Need a Crown Afterward
A root canal saves the tooth’s structure, but removing the pulp leaves it more brittle than a healthy tooth. Without its internal blood supply, the tooth becomes prone to cracking under chewing forces over time. That’s why most root-canal-treated teeth, especially premolars and molars, need a crown placed over them.
Dentists typically recommend getting the crown within one to two weeks of completing the root canal. Some offices can place one the same day if the tooth is stable and infection-free. Until the crown is in place, you’ll want to avoid chewing hard foods on that side. The temporary filling protecting the access hole isn’t designed for long-term use, and delaying the crown increases the risk of the tooth fracturing.
Long-Term Success Rates
Root canals have a strong track record. A 2023 study published in Clinical Oral Investigations found that 97% of root-canal-treated teeth survived after 10 years, with that number dropping to 68% after 37 years. The most common reasons for eventual failure are new decay around the tooth, a crack in the root, or reinfection of a canal that wasn’t fully sealed.
Getting a crown promptly and maintaining good oral hygiene are the two biggest things you can do to push your tooth toward the higher end of those survival numbers. A well-restored root canal tooth can function normally for decades.
What It Costs
The price depends heavily on which tooth needs treatment, because molars have more canals and take longer to complete. Here are typical 2025 cost ranges:
- Front teeth: $700 to $1,100 without insurance, roughly $200 to $500 with insurance
- Premolars: $800 to $1,300 without insurance, roughly $250 to $700 with insurance
- Molars: $1,000 to $1,600 without insurance, roughly $300 to $900 with insurance
These estimates assume 50% to 80% insurance coverage after your deductible and an in-network provider. The crown placed afterward is a separate cost, typically adding another $800 to $1,500 depending on the material and your location. Many dental offices offer payment plans to spread out the total expense.