An analysis was made of the clinicopathological features of 32 odontogenic keratocysts from 24 patients in the files of the 2nd Department of Oral surgery, Tohoku University, School of Dentistry. And the relationships between developmental odontogenic cysts and odontogenic keratocysts were discussed.
Case selection of odontogenic keratocysts was made on the basis of Pindborg and associates histologic criteria.
Odontogenic keratocysts were found in 16 males and 8 females. Patient age rangedfrom 13 to 62 years old. Peak incidence was in the second decade of life. The mandible: maxilla ratio was 2.2:1, with the mandibular third molar and ramus area being the most common site. The radiographic appearance of 27 regions of 32 odontogenic keratocysts inthis study could be described as having unilocular smooth periphery in 13 regions, a unilocular scalloped periphery in 8 regions, and a multilocular periphery in 6 regions.
Clinically, 12 odontogenic keratocysts were found in association with an impacted tooth, and 3 of these were of the dentigerous type.
Histologically, total parakeratinization was the most common finding and occurred in the epithelial lining of 29 cysts. In 3 cysts, the epithelial lining contained areasof parakeratinization and orthokeratinization. Budinglike proliferation of basal cells was found in the epithelial lining of 17 cysts.
Seventeen cysts contained islands or foci of odontogenic epithelium. Daughter cysts were present in 7 cysts.
In 19 cases permitting 1 year follow-up, 6 cases of recurrence were noted with arate of 32%. In this study, the rate of recurrence of cysts totally extirpated in one piece was only 8%, whereas the rate of recurrence of cysts removed in several pieces was 71%. We therefore considered that the most significant factor in the recurrence of odontogenic keratocyst was the incomplete extirpation of the cystic wall.