Root canal therapy becomes necessary when the inner nerve of a tooth becomes affected by decay, trauma, a crack or other elements. When this happens, the tooth may become extremely sensitive to pressure,temperature or intense pain can be expected without any stimulus. While diagnosing a tooth that needs a root canal treatment is usually straight forward, at times patient may not feel any or much discomfort when the X-rays show signs and other times when patient may feel pain or discomfort it is possible that the X-ray may not yet show anything. That is why a comprehensive examination relating all factors and considering all signs and symptoms along with the history of the tooth is necessary to make the proper diagnosis.
In the advanced stages, after the nerve has died and no treatment provided an abscess forms in the bone which could cause a new level of pain and swelling.
At times a pimple like opening will form on the gum near the tooth. This is where the abscess would drain out on regular basis making the infection almost painless but non the less harmful. Please seek treatment as soon as possible if you experience any of the above conditions.

When confronting a tooth that has nerve issues, the patient has two options:
save the tooth through root canal therapy or pull the affected tooth out.
While extraction maybe the only option at times, loss of a tooth is usually followed by new and added problems. Preventing new problems like shifting teeth, bone resorption, esthetic issues and bite problems, or fixing them once they arise could be more costly and demanding than if the tooth was saved through root canal therapy.
Saving a tooth with good structure through root canal therapy is still the preferred treatment option. There may be a need for re treatment of a previously root canalled tooth. This would only be necessary if a new infection arises.
The reasons a dentist will recommend root canal therapy include the following:

• Decay, crack or other causes has reached and or damaged the tooth pulp (the living tissue inside the tooth)
• Development of infection or abscess inside the tooth or at the root tip
• Trauma or injury to the tooth

While every tooth is unique and prognosis differs from one tooth to the other Root canal therapy can provide the possibility of saving a tooth for a long time and possibly a life time.