Transmission electron microscopy of supra-alveolar periodontal healing of auto- and allotransplanted teeth in monkeys.

An ultrastructural study of the supra-alveolar periodontal healing of auto- and allotransplanted teeth was performed in 4 immunologically unmatched green Vervet monkeys. Eight mature incisors were either auto- or allotransplanted. Non-transplanted adjacent incisors served as controls. Prior to transplantation the teeth were endodontically treated extraorally. Eight weeks after transplantation, biopsies including part of the tooth and the adjacent supra-alveolar tissues were taken, fixed, decalcified and processed for electron microscopy. A thin electron dense layer covered the root surface of the autotransplanted teeth. Most collagen fibres inserted into this electron-dense border, as well as into the underlying cementum. A similar relationship between the fibres and root surface was found in controls. On the allotransplanted teeth a layer of electron-dense granular material covered the root surface in the supra-alveolar area. Collagen fibres inserting into the electron-dense border were frequently observed. Fibroblasts were the predominant cell type in the connective tissue adjacent to all transplanted teeth. In autotransplants 2 morphotypes of fibroblasts were observed: 1) cells with dilated endoplasmic reticulum and swollen mitochondria; and 2) cells with normal characteristics of protein synthesis and secretion. The fibroblasts of the allografts were predominantly cells with dilated endoplasmic reticulum and swollen mitochondria. The results indicated some similarities in the healing between the root surface and connective tissue in the supra-alveolar portion of the roots of auto- and allotransplanted teeth.