Without treatment, the infection will spread, bone around the tooth will begin to degenerate, and the tooth may fall-out. Pain usually worsens until one is forced to seek emergency dental attention. The only alternative is usually extraction of the tooth, which can cause surrounding teeth to shift crookedly, resulting in a bad bite. 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.
Treatment usually involves one to three appointments.
First, you will probably be given a local anesthetic to numb the area. A rubber sheet is then placed around the tooth to isolate it. Next, a gap is drilled from the crown into the pulp chamber, which, along with any infected root canal, is cleaned of all diseased pulp and reshaped. Medication may be inserted into the area to fight bacteria. Depending on the condition of the tooth, the crown may then be sealed temporarily to guard against recontamination, or the tooth may be left open to drain, or the dentist may go right ahead and fill the canals.