Study on Homogeneic and Xenogeneic Tooth Transplantation. Special References to the Idiopathic Resorption of Transplanted Tooth of Dog

Using dogs as experimental animals, histopathological changes of transplanted teeth were investigated and compared to former results from monkey and human tooth transplantations. Special attention was given to the so-called idiopathic resorption of grafts in the present study. Autologous and homologous transplantations were carried out using adult dogs. Grafts were kept in a preservation medium from 2 weeks up to 2years at -20℃ before the transplantation. Grafts were inserted into the extraction sockets and then fixed by mucous sutures. Morphlogical changes of grafts were examined mainly by histological techniques making decalcified paraffin sections. The main results found in this study were as follows: (1) The most important finding was that the idiopathic resorption of grafts was remarkable compared to those of monkey or human tooth transplantations. Basically two types of idiopathic resorptions were observed. The first is resorption in the pulpal chamber, so-called idiopathic internal resorption, and the second is the resorption in the tooth-neck, so-called the idiopathic external resorption. (2) The idiopathic resorption was observed both in autografts and homografts. Thus, the relationship between the resorption mechanism and transplantation immunity was entirely obscure. (3) Based on the histology of the grafts, the idiopathic resorption of grafts was further classified into the following types: (a) internal type, (b) lateral and external type, (c) internal and external type, (d) crown missing type, (e) root missing type, (f) idiopathic-like type. Histopathological characteristics of each type were described and the possible causes of these variable resorptions are discussed.