Effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys.

The effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation was studied in green Vervet monkeys (Cercopithecus aethiops). Mandibular lateral incisors were extracted. The extra-alveolar period before replantation was 0, 18, 30, 60, 90, and 120 min. The storage media for the extracted teeth were tap water, physiologic saline, saliva or dry storage. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histometrically. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), periapical inflammatory changes, the extent of vital pulp and downgrowth of pocket epithelium. A significant relationship was found between the frequency of root resorption, extra-alveolar period and storage medium. This was especially evident after dry storage. Surface resorption was found with approximately the same frequency irrespective of extra-alveolar period and storage media. Inflammatory root resorption was especially common after dry storage and was related to the length of the extra-alveolar period. Already after 30 min dry storage, this resorption type was very prominent. Teeth stored in tap water, saline or saliva showed about the same frequency of inflammatory resorption, which increased slightly with increased extra-alveolar periods. Replacement resorption showed a strong relationship to dry storage and became very prominent after 60 min. Replacement resorption was rarely found among teeth stored in saline or saliva; whereas it was significantly increased among teeth stored in tap water. It is concluded that saline and saliva offer good protection against root resorption during the extra-alveolar period.