In this study, 12 patients diagnosed with benign cementoblastoma by radiographical and histopathological examination are reviewed. These patients were seen at Osaka Dental University in the Department of Oral Radiology in the 22-year period from April 1972 to December 1993. All tumors involved the mandible. Ten tumors occurred in the molar region and one tumor in the premolar region. Only one tumor occurred in deciduous dentition. There were 5 males and 7 females. The age of the patients at the time of diagnosis ranged from 7 to 47 years, with an average age of 26.0 years. The tumors were classified by radiopaque pattern into two types: homogeneous (type I, n=5) and mottled (type II, n=7). Almost all tumors were well defined and the central radiopaque area was commonly surrounded by a radiolucent zone of uniform width; only one tumor did not show this radiolucent zone. Condensation of the bone occurred in 11 of 12 tumors. Six of 11 tumors developed wide perifocal osteosclerosis of the bone, which was considered to be severe Type II. One patient showed a relapse approximately 18 months after surgical excision of benign cementoblastoma, and follow-up observation by radiographical examination is advisable for approximately 3-5 years after surgery.
