Your teeth are held in place by roots that extend into your jawbone. Front teeth usually have one root. Other teeth, such as your premolars and molars, have two or more roots. The tip of each root is called the apex. Nerves and blood vessels enter the tooth through the apex, travel through a canal inside the root, and into the pulp chamber, which is inside the crown (the part of the tooth visible in the mouth).
An apicoectomy may be needed when an infection develops or persists after root canal treatment,or retreatment. During root canal treatment, the canals are cleaned, and inflamed or infected tissue is removed. Root canals are very complex, with many small branches off the main canal. Sometimes, even after root canal treatment, infected debris can remain in these branches and possibly prevent healing or cause re-infection later. In an apicoectomy, the root tip, or apex, is removed along with the infected tissue. A filling is then placed to seal the end of the root.
An apicoectomy is sometimes called endodontic microsurgery because the procedure is done under an operating microscope.