A case Report of an Unusual Radicular Cyst Associated with Deciduous Toot

Introduction: Radicular and Residual cysts are by far the most common cystic lesions in the jaws which consist 50-75% of all oral cystic lesions. Radicular cysts have been considered rare in the primary dentition. It has been suggested that pathogenesis of radicular cysts in primary and permanent dentition could be different; although caries and pulp infection still are the most important of all. After extracting or shedding of the causative tooth, the cyst remains in jaws and from now on is considered a residual cyst.Case Report: A 12 year old female patient came to our clinic because of a painless swelling in the lower back region of her left jaw. According to surgical and microscopic findings, the lesion was diagnosed a radicular cyst associated with her 2nd deciduous molar which has had a pulp treatment. The cyst was enucleated.Conclusion: Although radicular cysts in deciduous dentition is considered to be rare, but it has been seen in primary molars treated endodontically which could be due to remaining of infection in inaccessible parts of root apex or periapical irritation with formocresol containing materials used in root canal filling. Assuming that the pathogenesis of radicular cysts is identical in primary and permanent dentition, the low frequency in the former is yet to be clarified.Key words: Deciduous tooth, pulp treatment, Radicular cyst, Residual cyst