Objectives: To determine the relative incidence of odontogenic cysts and to identify the main clinicopathological features among patients treated in the Oral Surgery Department of the Dental Clinic of the University of Barcelona (Spain). Study design: A retrospective observational study was made of 418 odontogenic cysts diagnosed in 380 patients included in the database of 1235 histopathological diagnoses. The subjects were treated in the Master degree program of Oral Surgery and Implantology of the University of Barcelona in the period 1997-2006. The following variables were recorded: gender, age, clinical characteristics of the lesions (size and location), radiological features, duration, treatment, complications and relapses. A descriptive analysis was made of the study variables, using the SPSS version 15.0. Results: The incidence of odontogenic cysts was 33.8%. The mean patient age at appearance of the lesion was 42 years (range 7-83). The cysts were slightly more prevalent in males (58.4%). The lesion size ranged from 2-60 mm, with a mean size of 18.4 mm. The most frequent diagnosis was radicular cyst (50.2%). The most common location of the odontogenic cysts was in the mandible (61.5%), particularly the lower third molar region (36.8%). Conclusions: The most frequently diagnosed lesion was the radicular cyst. Odontogenic cysts were seen to be slightly more prevalent in males, and showed a high mandibular incidence. Knowledge of the biological and histological behavior of odontogenic cysts and their frequency are key aspects for ensuring early detection and adequate treatment.

IntroductionFlorid cemento-osseous dysplasia is a non-neoplastic fibro-osseous lesion which often has an asymptomatic slow growth. Unfortunately, these lesions are usually diagnosed through routine radiographic examination. The aim of this study was to describe the main clinical, radiological and histological characteristics of two case reports diagnosed with florid cemento-osseous dysplasia.Case reportsTwo cases of florid cemento-osseous dysplasia with different clinical and radiological features were presented. Panoramic radiographs showed multiple radiopacities compatible with fibro-osseous lesions in distinct areas of the maxillary bones. The histological study revealed a sclerotic mass which continued imperceptibly with root cement with scarce fibrous lax tissue.ConclusionsThe replacement of healthy bone by metaplastic bone and fibrous tissue is the main histological feature. Therapeutic abstention with active clinical and radiographic control visits is recommended in asymptomatic cases. Key words:Fibro-osseous lesions, cemento-osseous dysplasia, florid cemento-osseous dysplasia, gigantiform cementoma, osseous dysplasia.