Among 29 primary cases of mandibular ameloblastoma treated in a 21-year interval from September, 1975 to August, 1996, we conducted an additional investigation of l8 cases in which conservative therapy was pursued to investigate indications of conservative therapy for mandibular ameloblastoma by clarifying their clinical courses, recurrence sites, and treatments. Recurrence was seen in 3 cases (16.7%); their radiographic examinations were unilocular in 2 cases and multilocular in l case, and their histological examinations had a plexiform pattern in 3 cases. Tumor recurrence occurred in 3 out of 18 cases (16.7%). Causes of recurrence were deemed to be an overlooked tumor near the original site of the mandible in l case and a residual tumor peripheral to the mandibular canal or the mesial tooth germ in 2 cases. Even in cases of recurrence, we treated them by conservative therapy of the mandible, and they have remained in good condition.
