Selection of allogenic tooth graft using HLA-A, -B, -C and DR typing and the MLC test

Re- and allotransplantation of teeth--an experimental study in monkeys

In each of six monkeys one of the permanent lateral incisors with uncompleted root development was replanted. At the same time the contralateral incisors in four of the monkeys were allotransplanted by pairs. The remaining two contralateral incisors served as controls. After 4 weeks and 4 months, respectively, three monkeys were decapitated and the upper lateral incisors with adjacent periodontal tissue were examined histologically. The replanted teeth in five cases had a vital pulp. In the sixth case, however, the replanted incisor exhibited pulpitis and partial necrosis of the pulp. The periodontal membrane had a normal histologic appearance. In two cases a small area of arrested root resorption was observed. With the allotransplanted teeth the histologic appearance was altered. After 4 weeks a pronounced inflammatory reaction was observed in both the pulpal tissue and the periodontal membrane. The pulp was in most cases necrotic, and marked root resorption was observed. Most of the allotransplanted teeth were resorbed and replaced by an irregular hard tissue that resembled osteoid, which in many cases was connected with the tooth remnants by ankylosis. These results indicate that allotransplanted teeth, in contrast to replanted teeth, exhibit the characteristic features of an allograft rejection, including an inflammatory reaction and resorption.

Allotransplantation of human teeth. A retrospective study of 73 transplantations over a period of 28 years

An assessment was made of the postoperative fate of 73 allotransplanted human teeth carried out by 3 surgeons between 1956 and 1980 to determine the clinical and radiographical course of immunogenetically unmatched allotransplanted human teeth. The mean ages of recipients and donors were 34.1 and 15.2 years, respectively; 47 of the grafts had incomplete root-formation at time of transplantation. Mean observation period was 7.8 years with a maximum of 28 years. The study was terminated December 1985. The mean functional time of the grafts (function of graft without symptoms) was 6.8 years (max. 28.5 years). No signs of pulpal survival were found in any graft. Root resorption was found in 91.6% of grafts within a mean of 8.8 months after transplantation, causing a high frequency of graft loss within the first 2 years (34.1%). Recipients older than 45 years of age retained the grafts significantly longer than young patients. The major causes of graft loss were replacement (60.3%) and inflammatory resorption (24.4%). Graft loss due to marginal periodontitis was minor (2.7%). Inflammatory resorption, which was found more frequent in young recipients (P = 0.02), usually caused rapid rejection, whereas the survival time after ankylosis was significantly longer. In conclusion, no clinical or radiographical evidence of long-term survival of the pulpal or periodontal tissues of the unmatched allografts were found. However, despite a progressing replacement resorption frequently present, the allografts seem to function clinically sufficient, symptomless and often with clinically normal gingival condition for many years. Increasing age of the recipient at time of transplantation significantly increased the function time of the graft. Younger recipients showed more inflammatory resorption of the grafts.