Study on Allogeneic and Xenogeneic Tooth Transplantation : Changes of Tooth Supporting Tissue in Allogeneic Transplantation observed using Conventional and Polarized Light Microscope

The morphological changes of the allogeneically transplanted teeth and the tooth-supporting tissue in dogs were examined using ordinary and polarized light microscope. Twenty-eight (80%) out of 35 teeth transplanted to seven dogs were successful, remaining seven teeth (20%) unsuccessful. Ten deys after transplantation, resorption of the cementum was observed as small pits. On the 30th day it proceeded into cementum and a part of dentin. On the 70th day, most of the cementum and about one third of dentin were resorbed. These findings were more prominent where the periodontium of the tansplant was less preserved. On the 10th day, small amount of osteoid was observed in the periphery of the alveolar bone, where marked proliferation of osteoblasts were seen on the 30th day. On the 50th day, transplanted teeth were ankylosed to the alveolar bone by the osteoid tissue, which converted to hard osseous tissues on the 80th day. Under polarized light, collagen fibers in the osteoid showed loose and irregular arrangement on the 30th day, and lamellar arrangement of newly formed osseous tissue was seen in the parts of adhesion on the 70th day. These findings suggested the significance of the preservation of periodontium against the resorption, and the possible mechanisms of ankylosis are discussed.