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 of the canals inside a tooth's root. Decades ago, root canal treatments often were painful. With dental advances and local anesthetics, most people have little if any pain with a root canal. In fact, it's probably more painful living with a decayed tooth. Root canal alternatives include extracting the damaged tooth and replacing it with a dental implant, bridge or removable partial denture.

Teeth have a soft core called dental pulp. The pulp extends from the crown — the visible part of the tooth — 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 has a deep cavity, bacteria can enter the pulp. Left untreated, bacteria and decaying material can cause a serious infection or a tooth abscess, leading to pulp death, bone loss and loss of the tooth itself. Signs and symptoms may include swelling around your face and neck, a hole in your tooth, toothache or tooth pain, gum swelling, and temperature sensitivity.

A root canal is usually done by an endodontist or a general dentist. The root canal usually takes one or two visits, but once in a while additional visits are required because some teeth prove difficult to treat. First, you have dental X-rays to check the extent of damage. You also receive a local anesthetic to control pain, which may be more severe if the tooth is abscessed. Then a rubberlike sheet called a dental dam is put in your mouth to keep the tooth clean, protected and free of saliva. Decay is removed, and an opening is made through the crown of the tooth to gain access to the pulp chamber. Using small dental instruments, the infected or diseased pulp is removed.

After the diseased pulp is removed, the pulp chamber and root canals are flushed and cleaned. The root canals may be reshaped and enlarged to allow better access for filling later. Before permanently filling the root canals, they should be clean of all infection and dried. Medication is sometimes put into the pulp chamber and root canal to clear any infection. The tooth may be left open to drain for several days. If infection has spread beyond the tooth, you may need a prescription for antibiotics. If the root canal requires multiple visits, a temporary filling is placed in the crown to protect the tooth and keep out debris and saliva. Avoid biting or chewing on the tooth until it's been treated and restored.

After cleaning and drying, it's time to fill the interior of the tooth — the empty pulp chamber and root canals. You may not need additional anesthetic for this step. If you had a temporary filling placed, that will be removed to allow access to the inside of the tooth. A sealer paste and rubber compound is used to fill the tooth, followed by a dental filling to make sure the root canals are protected from saliva.

The final stage of the root canal is restoring your tooth. Because the tooth typically has a large filling or is weakened from extensive decay, it needs to be protected from future damage and returned to normal function. This is usually done by placing a crown — a realistic-looking artificial tooth. A crown is made of gold, porcelain or porcelain fused to metal. Crowns made of porcelain or porcelain fused to metal can be tinted to match the color of your other teeth. Sometimes, a metal post must first be inserted in the tooth for structural support and to keep the crown in place. Ask your dentist or endodontist about other restoration options.

After your root canal, your restored tooth with the new crown should work normally and look cosmetically pleasing. If you follow good dental and oral hygiene, your restored tooth could last a lifetime. The first few days after your root canal, the tooth may be sensitive. Over-the-counter pain medications can help. If pain or pressure lasts more than a few days, be sure to talk to your dentist or endodontist.