Periodontal ligament vitality and histologic healing of teeth stored for extended periods before transplantation.

A previous study evaluated the viability of dog periodontal ligament cells as indicated by tritiated thymidine uptake after extended storage in Hank's balanced salt solution and Conditioned Medium. The purpose of this study was to evaluate histologic healing following the identical storage parameters established in the earlier study. Additionally, for Conditioned Medium, matched pairs (teeth evaluated for tritiated thymidine uptake and transplanted teeth) were examined in an attempt to correlate periodontal ligament vitality and healing. Forty-six extracted endodontically treated dogs' teeth were randomly grouped and stored in Hank's balanced salt solution or Conditioned Medium for 6, 48, and 96 h and then transplanted into 6-, 48-, and 96-h sockets. The control group teeth were transplanted without storage into 6-, 48-, or 96-h sockets. After 6 months the dogs were killed and the teeth were prepared for histologic evaluation according to Andreasen. Complete healing, inflammatory root resorption, and replacement resorption were evaluated and compared. Overall, significantly better healing was observed for teeth stored in Conditioned Medium than for teeth stored in Hank's balanced salt solution. Conditioned Medium was not significantly different from controls. Additionally, there was a positive correlation between periodontal ligament viability and healing for Conditioned Medium. These results confirmed the importance of periodontal ligament viability in successful replantation and the potential of Conditioned Medium as a storage medium for avulsed teeth.

The role of the socket in the periodontal healing of replanted dogs' teeth stored in ViaSpan for extended periods.

In a previous study on the extended storage of extracted dogs' teeth, it was hypothesized that changes in the socket environment might play a role in the periodontal healing of these teeth. The purpose of this study was to evaluate the role of the socket in the periodontal healing of replanted dogs' teeth. Extracted endodontically treated dogs' teeth were stored in ViaSpan for 6 hours and replanted into sockets after 6, 48 or 96 hours. Controls included teeth extracted and replanted immediately, 48-hour stored teeth replanted into 48-hour sockets and 96-hour stored teeth replanted into 96-hour sockets. After 6 months the dogs were killed and the teeth prepared for histologic evaluation according to Andreasen. Overall healing for the groups and healing for teeth within the groups were evaluated and compared. The best results were obtained when the teeth were replanted immediately. For the teeth stored in ViaSpan for 6 hours, complete healing decreased significantly as the age of the socket increased. In addition, the rate of replacement resorption increased significantly with increasing socket age for the 6-hour stored teeth. Forty-eight-hour stored teeth replanted into 48-hour sockets had the lowest healing rate with levels of inflammatory resorption not seen in the other groups. According to the results of this study, the socket environment plays an important role in the healing of replanted teeth in dogs.

Tritiated thymidine uptake in periodontal ligament cells of dogs' teeth stored in various media for extended time periods.

The purpose of this study was to evaluate a new storage solution, Conditioned Medium, vs Hank's balanced salt solution and ViaSpan with respect to the viability of periodontal ligament cells of exarticulated teeth. Teeth were stored for periods of 6, 48, and 96 hours in Hank's balanced salt solution, ViaSpan (Dupont Pharmaceuticals), or Conditioned Medium. Teeth were cultured for 24 hours in Dulbecco's medium supplemented with tritiated thymidine. The cultured teeth were sectioned and evaluated with autoradiography. Control teeth were extracted and immediately treated as above without storage. Mitotic activity was indicated by clusters of five or more grains over the nuclei of fibroblasts in the remaining periodontal membrane. The ratio of labeled to unlabeled cells (labeling index) was calculated for each treatment group. When storage time was compared across all groups, 96 hours was significantly different from 6 and 48 hours (P < 0.001 and P < 0.012 respectively). Storage time of 6 hours was not significantly different from 48 hours (P > 0.10). After comparison of the nine experimental groups with the control group, only Hank's balanced salt solution at 96 hours was significantly different (P < 0.004).