2002 年 15 巻 1 号 p. 10-16
It is known that the success of tooth transplantation depends on the preservation of the periodontal ligament. The purpose of this study was to investigate the effect of long-term cryopreservation of the tooth with periodontal ligament in terms of cell activity in vitro.
The teeth with periodontal ligament were obtained from beagle dog and cryopreserved for 6 months,1 year and 2 years in the liquid nitrogen.Cryopreserved teeth for each period were thawed in a water bath at 37℃, and periodontal ligament tissues were cultured in α-MEM supplemented with 10%FBS and antibiotic solution. In the control group, periodontal ligament tissues were cultured immediately after the tooth extraction. After subculture, cells were plated in 35 mm cell culture dishes at a concentration of 1 × 105 cells per dish.Either cell transmigration or confluent periods at the primary culture were investigated. Proliferation ratio, alkaline phosphatase(ALPase)activity and the positive ratio of proliferating cell nuclear antigen(PCNA)were also examined.
Either cell transmigration or confluent periods were prolonged in the experimental groups compared to those of control group(p＜0.05), However, no statistical difference was found in either the cell proliferation ratio or ALPase activity of any time period of the experimental groups compared to those of the control group. Furthermore, there was no significant difference in the PCNA positive cell ratio in all groups.
The results suggested that cryopreservation delayed the cell transmigration period from the tissues because the cells received damage to tissue or DNA in the cryopreserved environment and it took time to repair the damage. However, after repairing the cells, there was no significant difference between experimental and control groups in terms of cell proliferation and differentiation. In this study, it can be considered that there is no effect of long-term cryopreservation on periodontal healing in the case of tooth transplantation or replantation.
