Study　on Allogenic and Xenogenic Tooth Transplantation : Observation of Tooth Supporting Tissue in Xenogenic Transplantation from Man to Monkey.

Experiments on xenogenic tooth transplantation (from man to monkey) were performed in order to study the actual state of genetic make-up of allogenic tooth transplantation. In the present study, tooth supporting tissues of the recipient was histopathologically examined. Twenty-three cases out of 30 cases (about 80%) were successful, while remaining seven cases (about 20%) were unsuccessful. The latter included one case of cadavaric tooth graft. Compared to cases of allograft transplantation, the influence of xenograft -antigen stimulation seemed to be weak unexpectrdly, although the intial cell response was notable. Though various types of graft resoptions were observed, the most dominant was the resorption with ankylosis. The condition of attachment of the tooth grafts to tooth supporting tissues of the recipients was different in different parts of the graft , i. e. the gingival third, the middle third and the apical third. In the gingival third, the condition of attachment proved to be excellent. However, in the middle third and the apical third, the attachment was partial. The following 3 types of tissue changes were observed in the periodonal tissues of the recipients. The first type was the resorption of the graft ankylosis, which was the most dominant type, and which spread throughout the entire regino of the dental root similar to the hinge-like attachment of the fish tooth. In the second type of tissue chauge, no graft resorption was observed and the alveolar bone became dense after remodeling itself. In this case, the periodontal tissues were destroyed, and the grafts seemed to stay in the sockets due only to the persence of rough granulation. One variation was an intermingled type of bone reabsorption and fiber formation. The last type was seen in the case of cadavaric pulp tooth graft. In this type, chronic abscesses were observed around the apical collateral route. Frequently, the abscesses to spread to the entire area of the tooth supporting tissues. The immunological and pathological significance of these histological changes in the recipient tooth-supporting tissues was also discussed