Cryopreservation as long-term storage of teeth for transplantation or replantation

A method is presented which for the first time demonstrates the possibility of storing a human tooth over a period of 18 months in a frozen state with the periodontal membrane preserved viable, enabling the thawed tooth to heal with a normal periodontal ligament evaluated 2 years after autotransplantation. The cryopreservation technique included equilibration of the extracted tooth into 10% DMSO (dimethylsulphoxide) at room temperature in tissue culture medium including 10% human serum, freezing with a controlled rate of 1.2 degrees C/min to -40 degrees C and 6 degrees C/min to -100 degrees C, followed by transfer to and storage in liquid nitrogen at -196 degrees C. The tooth was thawed at a fast rate of approximately 100 degrees C/min, and DMSO was removed by slow equilibration at room temperature. A mature human bicuspid was autotransplanted after cryopreservation. Endodontic treatment was initiated 4 weeks after transplantation. 2 years after transplantation, the grafted tooth showed clinically and radiographically normal periodontal healing without signs of root resorption or marginal bone loss.