Anesthetic before root canal greatly reduces pain

Q. I have to have a root canal. Why do I need it? And what will happen during the procedure?

A. If you've never had a root canal, and if you've heard someone say, “I'd rather have a root canal than have ...” you probably think it's very painful. I've had several root canals. They're no fun, that's for sure. But you get an anesthetic before the procedure that greatly reduces or eliminates the pain.

Every tooth has roots that anchor the tooth in the bone of the jaw. Teeth have a hollow central chamber, or canal, that is inside both the body and the roots of the tooth. Inside the hollow chamber is an inner pulp that contains a network of nerves, blood vessels and tissues. The pulp helps nourish your tooth and also relays sensory information. That's why injury or damage near the pulp evokes pain.

Pulp damage can cause a range of symptoms, including tooth sensitivity, pain, swelling or tenderness of the gums, cracked or discolored teeth, nerve death and infection.

Among the most common causes of pulp damage are tooth decay and advanced gum disease, which can cause infection in and around the teeth. A bacterial infection in the pulp usually kills the nerves. The infection can then spread to the gum and mouth tissues and beyond.

Root canal therapy removes damaged or diseased pulp and seals off the inner chamber that normally contains it. This prevents the infection from spreading.

The process usually takes two to three office visits. During the first visit, the endodontist (a dentist who specializes in problems with dental pulp and nerves) will inject a local anesthetic. He or she will drill a hole in your tooth and remove the decayed or diseased pulp.

The endodontist will clean the root canal, removing bacteria, tooth fragments and tissue. An antiseptic (and sometimes also antibiotics) will be injected into the pulp chamber to kill remaining bacteria.

The root canal and pulp chamber will be dried, then filled with a permanent filling material. This material replaces the pulp.

After the root canal treatment is complete, your dentist will place an amalgam (a “filling”) or composite restoration, a crown, or both on your tooth. This will protect and strengthen your tooth and help maintain its structure.

There are two pieces of good news to close with. Fifty years ago, many teeth with infected pulp could not be saved. Now, a root canal procedure preserves teeth. Farther back, closer to 150 years ago, there were no powerful anesthetics, so you lost your tooth only after suffering a lot of pain. No one wants to have a root canal, but at least today we have a technology that preserves our teeth and minimizes the pain.

• Dr. Komaroff is a physician and professor at Harvard Medical School. Go to his website to send questions and get additional information: AskDoctorK.com.