Evaluation of different types of autotransplanted connective tissues as potential periodontal ligament substitutes. An experimental replantation study in monkeys.

The purpose of the present study was to investigate connective tissue autotransplants as potential periodontal ligament substitutes. Green Vervet monkeys (Cercopithecus aethiops) were used. Maxillary permanent central incisors were extracted, root filled extraorally and the periodontal ligament removed from the root surface and the socket wall. Two circular cavities were prepared mesially and distally on the root surface. Different types of connective tissue autotransplants were then placed in these cavities, whereafter the teeth were replanted. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histometrically. The connective tissue autotransplants were then examined for their capability of preventing root resorption or inducing or forming a new periodontal ligament, including periodontal fibers and cementum. Autotransplanted cutaneous and mucosal connective tissue as well as periosteum and fascia were all found to partially prevent ankylosis by forming a fibrous barrier between the root surface and the alveolus. However, no new cementum was formed. Periodontal ligament transplants, dental follicular tissue and possibly gingival connective tissue were the only tissues capable of both preventing ankylosis and forming a hard tissue on the surface of the cavity with a morphology similar to cementum. It is concluded that cementogenesis requires a highly specialized connective tissue. In this experiment, only odontogenic tissues had this capacity.