Proliferation kinetics-study of the growth of keratocysts. Morpho-functional explanation for recurrences.

The mode of growth of the odontogenic keratocyst is of decisive importance in the strategy and radicality of its surgical removal. The high rate of recurrence reported in the literature is striking. Staining with haematoxylin-eosin for histological examination provides only limited information on growth. Serial sections of a keratocyst obtained by fractionated curettage were prepared and the proliferation patterns of epithelium and connective tissue were studied by means of autoradiography and DNA cytophotometry and compared with those of an odontogenic reference cyst of the radicular type. The epithelium of the keratocyst examined clearly showed a higher rate of proliferation than that of the radicular cyst. The connective tissue was also growing very actively with a high rate of proliferation and this growth behaviour is at least partly responsible for the invasive and destructive growth of the keratocyst. In contrast to the radicular cyst, proliferation of the epithelium of the keratocyst is multicentric being simultaneous within the growth centres. As a result the epithelium "buds" with formation of satellite cysts in the alveolar bone and peripheral epithelial islands located in the connective tissue. A case is reported of a keratocyst treated by radical curettage with subsequent freshening of adjacent bone with a bur. Our morphological findings are an important contribution to the present discussion of the various methods of treating keratocysts.