What is a root canal?
Underneath your tooth's outer enamel and within the dentin is the pulp, an area of soft tissue that carries the tooth's nerves, veins, arteries and lymph vessels. Root canals are very small, thin divisions that branch off from the top pulp chamber down to the tip of the root. A tooth has at least one but no more than four root canals.

Why do I feel pain?
When a deep cavity, tooth fracture, or injury to the tooth, allows bacteria to seep in, the pulp can become infected and die. Damaged or dead pulp causes increased blood flow and cellular activity, and pressure cannot be relieved from inside the tooth. Pain in the tooth is commonly felt when biting down, chewing on it and applying hot or cold foods and drinks.

Why do I need root canal therapy?
Because the tooth will not heal by itself. Without treatment, the infection will spread, bone around the tooth will begin to degenerate, and the tooth may fall out. Pain usually worsens until the patient seeks emergency dental attention. The only alternative is extraction of the tooth.  Though an extraction is cheaper, the space left behind will require an implant or a bridge, which can be more expensive than root canal therapy. If you have the choice, it's always best to keep your original teeth.

Here's how your tooth is saved through endodontic treatment.

After care instructions for ROOT CANAL TREATMENT
Your root canal treatment may take one or more visits to complete. During treatment, your dentist will remove the diseased pulp, then clean, shape and fill the root canal to prevent recontamination. These instructions will help answer some of your questions about what to expect and how to take care of your mouth after treatment.

What to Expect after Treatment

• Because cleaning the root canals may cause inflammation of tissue surrounding the tooth, you may experience some discomfort for a day or so.  Over-the-counter analgesics usually alleviate the discomfort. 
• Talk with your dentist about which medication to take.  If the discomfort continues, or if you have severe pain or swelling, call your dentist.
• Between appointments a temporary medicated filling or crown is placed. It is not uncommon for these soft medicated fillings to partially wear between appointments. Because temporary restorations will eventually loosen, see your dentist promptly following completed root canal treatment for a final restoration.
• Sometimes antibiotics are prescribed to help control infection.  Please take all medication as directed.  Antibiotics are not routinely prescribed to reduce the chance of developing a resistance to them.

How to Take Care of Your Mouth

• Avoid chewing or biting directly on the treated tooth until your dentist replaces the temporary restoration.
• If medication is prescribed, take it only as directed.
• Return for a follow-up exam after treatment as directed to make sure there has been proper healing of the tissues surrounding the tooth root.

Retreatment May Occasionally be Necessary
Even though the pulp of the tooth was removed, the tooth is still nourished from surrounding tissues. As with any living tissue, treatment is occasionally unsuccessful and a retreatment, or removal of the tooth, may be necessary.