LEEMING, B.*, GABRIEL, E. (Department of Prosthetic Dentistry and Department of Experimental Surgery, University of Würzburg/Germany)
Transplantation of natural teeth needs a preservation of the transplant for short or longer periods [Schwartz and Andreasen 1986]. The dynamic-mechanical behavior - the elasticity and the viscoelasticity - of dentine (three test groups with each 12 specimens, and three control groups with each 12 specimens (sum = 72 specimens) was investigated in following cryopreservation methods:
1.) Deep-freezing to -25°C without antifreeze (for 7 days)
2.) Defined freezing-rate (1,2°C/min.) with antifreeze to -40°C, then increased freezing-rate (6° C/min) to -100° C and storage in fluid nitrogen at -196°C (for 7 days).
3.) Freeze-drying after defined freezing-rate (1,2° C/min.) with antifreeze to -40° C, then dry storage at 7° C (for four days).
With method 1.) and 3.) the elasticity of the dentine decreased by 40%. With the method 2.) the elasticity increased by 10%.
For cryopreservation - as a long-term storage method for teeth - freezing with defined freezing rate and usage of antifreeze (DMSO) causes good dynamical properties of the dentine after trawing . This is important due to later prosthetic and filling therapy in cryopreserved and transplanted teeth. The data are statistically evaluated and the recommended preservation method shows significantly better results in the elasticity behavior of the specimens then in the other preservation methods.