Odontogenic cysts: a clinical study of 695 cases.

The aim of this study was to analyze the files of 695 consecutive patients operated on under general anesthesia for odontogenic cysts in an adult French teaching hospital for comparison with findings in world surveys. A retrospective survey of cysts of the jaws was undertaken at the Maxillofacial department, Pitié-Salpêtrière University Hospital, Paris, France. Data were retrieved from case notes, imaging, histopathology records and follow-up reports from January 1995 to January 2005. The mean age of patients was 41.8 +/- 15.8 years. There was an overall male to female ratio of 1.86:1. Mandible to maxilla ratio was 3:1. Regarding the mandible, the angle was involved in 36% of the cases, horizontal branch in 32%, parasymphysis in 18%, ramus in 11.6%, coronoid process in 1.5% and condyle in 0.9% (total = 100%). Regarding the maxilla, the canine to canine region was involved in 40% of the cases, premolar and molar region in 45%, and wisdom tooth region in 15% (total = 100%). The three most frequently diagnosed odontogenic cysts were radicular cysts (53.5%), dentigerous cysts (22.3%) and odontogenic keratocysts (19.1%). Together, these three entities represented 94.9% of all odontogenic cysts. The mean number of operation per patient was 1.16 (SD: 0.6, range: 1-10). The mean cumulated duration of hospitalization for one patient was 2.46 days (SD: 1.9, range: 1-28). The mean length of follow-up was 8.4 months (SD: 15.2, range: 0-120). Sixty five percent had a follow-up inferior to 6 months and 18% had no follow-up at all. The two most important findings of this case series are 1) the important number of radicular cysts that could be avoided because most of these cysts develop as a consequence of advanced carious lesions and 2) regarding other types of cysts, the dramatic rate of patients lost to follow-up.