In my experience, I have found that only about 4% of root canals fail. The failure can result from:

• Unusual and undetectable tooth anatomy.
• Small accessory and lateral nerve canals that can not be instrumented.
• Cyst formation

About 90% of the "failures" can be saved with a surgical procedure called an apicoectomy. This involves the removal of the the root tip of the tooth and the placement of a filling at the end of the root. There can be abnormal root anatomy  and lateral canals present which exit at the tip of the root. Part of the procedure is to clean or curettage the are at the end of the root to remove any granulation (scar) tissue and cystic formations which might be there.

In most cases the apicoectomy is an in-office procedure. The area is numbed with a local anesthetic and you may have IV sedation or nitrous oxide to relax you. Pain medication will be prescribed to take care of any post operative discomfort. The area may be sore for about three days.

The gum is lifted from an area adjacent to the root area. Access to the root is then made through the thin bone covering the root. A portion of the the root tip is then removed.

The area around the root tip is then cleaned and curetted. The gum is placed back into position and "stitched". Notice the area of bone loss in the x-ray above.

This x-ray and drawing show the same area when x-rayed several months later. Notice where the abcess (dark spot) was, has filled in indicating healing and the filling in of bone.