Root canal is a treatment to repair and save a badly damaged or infected tooth instead of removing it. The term "root canal" comes from cleaning out the canals inside a tooth's root.

Decades ago, root canal treatments often were painful. With dental advances and numbing medicine known as a local anesthetic, most people now feel little or no pain during a root canal. In fact, it's probably more painful living with a decayed tooth.

Options other than a root canal include removing the damaged tooth with no more treatment or removing and replacing the tooth with a dental implant, bridge or removable partial denture.

Teeth have a soft core called dental pulp. The pulp extends from the crown, which is the part of the tooth you can see, to the tip of the tooth's root in the jawbone. The pulp contains nerves, blood vessels and connective tissue.

When a tooth is cracked or chipped or has a deep cavity, bacteria can enter the pulp. Injury to the tooth also can cause pulp damage and inflammation. If not treated, bacteria and decaying material can cause a serious infection or a collection of pus called an abscess. This can lead to pulp death, bone loss and loss of the tooth itself. Symptoms may include swelling around your face and neck, a hole in your tooth, toothache or tooth pain, gum swelling, and being sensitive to hot or cold drinks or food.

A root canal usually is done by a general dentist or a specialist called an endodontist. The root canal usually takes one or two visits. Sometimes more visits are needed because some teeth are harder to treat.

First, you have dental X-rays to check the amount of damage to your tooth. You also get numbing medicine to control pain during the procedure. A rubberlike sheet called a dental dam is placed in your mouth around the tooth to keep the tooth clean, protected and free of saliva. Your dentist or endodontist removes the decay and makes an opening through the crown of the tooth to get to the pulp chamber. The infected or diseased pulp is removed using small dental instruments.

After the diseased pulp is removed, the pulp chamber and root canals are flushed and cleaned. The root canals may be reshaped and made larger so it's easier to get into them for filling. The root canals are cleaned of all infection and dried before they are permanently filled. Medicine sometimes is put into the pulp chamber and root canals to clear any infection. If the infection has spread beyond the tooth, you may need a prescription for antibiotics.

After the root canal, you may have a short-term filling called a temporary filling. This is placed in the crown to protect the tooth and keep out food bits and saliva. Avoid biting or chewing on the tooth until it's been permanently treated and restored.

After the tooth has been cleaned out and dried, it's time to fill the inside of the tooth, including the empty pulp chamber and root canals. You may not need more numbing medicine for this step. If you had a temporary filling, it's taken out to get inside the tooth. First, a sealer paste and rubber compound is used to fill the root canals. After this, a dental filling is placed to protect the root canals from saliva.

The final stage of the root canal is restoring your tooth. The tooth typically has a large filling or is weakened from a large area of decay. The tooth needs to work well again and needs protection from future damage. This is usually done by placing an artificial crown. A crown is a realistic-looking artificial cap that's placed over the tooth.

A crown typically is made of gold, porcelain or porcelain fused to metal. But other materials may be used. Crowns made of porcelain or porcelain fused to metal can be tinted to match the color of your other teeth. If a lot of the tooth structure is missing, you may need a metal post placed in the tooth for support and to keep the crown in place. Ask your dentist or endodontist about other options for restoring your tooth.

After your root canal, your restored tooth with the new crown should work like a natural tooth and look pleasing. If you follow good dental and oral care, your restored tooth could last a lifetime.

The first few days after your root canal, the tooth may be sensitive. Pain medicines that you can buy without a prescription may help. If pain or pressure lasts more than a few days, talk to your dentist or endodontist.

Aug. 09, 2025

Original article: https://www.mayoclinic.org/zh-hans/diseases-conditions/tooth-abscess/in-depth/root-canal/art-20585454