A: Impacted teeth can be painful and lead to infection.They may also crowd or damage adjacent teeth or roots. More serious problems may occur if the sac surrounding the impacted tooth becomes filled with fluid and enlarges to form a cyst. As the cyst grows it may hollow out the jaw and permanently damage adjacent teeth, the surrounding bone and nerves. Rarely, if a cyst is not treated, a tumor may develop from its walls and a more serious surgical procedure may be required to remove it. Despite the considerable concern regarding impacted third molars, a recent study sponsored by the American Association of Oral and Maxillofacial Surgeons and the Oral and Maxillofacial Surgery Foundation finds that third molars which have broken through the tissue and erupted into the mouth in a normal, upright position may be as prone to disease as those third molars that remain impacted.