Benign fibro-osseous lesions are demonstrated as a group of conditions, which normal bone is replaced by a connective tissue matrix that gradually develops cemento-osseous tissue and include developmental lesion, reactive lesion, dysplasia and tumor. Cemento-osseous dysplasia is one of benign fibro-osseous lesions, which is non-neoplastic process. Histologic features of cemento-osseous dysplasia are admixtures of bone and cementoid materials in a fibrous stroma. Cemento-osseous dysplasia associated with traumatic bone cysts has infrequently been reported. Traumatic bone cyst is a pseudocyst that may befound in both the jaws and the long bones. Though blockage of interstitial fluid drainage orvenous obstruction may be the cause of traumatic bone cyst, the exact pathogenesis of traumatic bone cysts is unknown. Melrose et al. was the first to report association of cemento-osseous dysplasia and traumatic bone cystsin their series. It is assumed that different mechanism is involved in cyst formation in these cases. This report presents review of literature and describes a case of focal cemento-osseous dysplasia associated with traumatic bone cyst of the mandible and its surgical treatment.

Florid cemento-osseous dyspl잃ia with concommitant traumatic bone cyst is uncommon condition. We report a case of florid cemento 。，sseous dysplasia involving four quadrants of the jaws and associated with large cystic lesion of the mandible misdiagnosed as a multiple odontogenic keratocysts in a 37-year-old Korean woman. Histological examination revealed unencapsulated fibroblastic proliferation with formation of bone and cementum, showing different developmental stages, and cys디c lesions resembling a traumatic bone cyst.