Interrelation between alveolar bone and periodontal ligament repair after replantation of mature permanent incisors in monkeys

Interrelation between alveolar bone and periodontal ligament repair was studied in green Vervet monkeys. Maxillary central incisors were extracted. The storage medium for the extracted teeth was saline in an 18 min. extra‐alveolar group and dry storage in a 120 min. extra‐alveolar group. In the experimental groups, the labial bone plate was removed surgically and the teeth replanted. In the control groups, teeth with similar extra‐alveolar periods were replanted into sockets with intact labial bone, The animals were sacrificed 8 weeks after replantation and the replanted teeth examined histometrically. Root resorplion and the position of the labial bone in relation to the cemento‐enamel junction were registered for each tooth. A significant relationship was found between the extent of labial bone repair and the extra‐alveolar period. Thus, teeth with I8 min. extra‐alveolar period showed almost complete repair of the labial bone plate, whereas teeth with an extra‐alveolar period of 120 min. showed a mean position of labial bone 3.7 mm from the pocket epithelium. The extent of root resorption was influenced by the extra‐alveolar period alone and not by the presence or absence of alveolar bone. It is concluded that a vital periodontal ligament upon replanted mature teeth is able to induce the formation of new alveolar bone.