Evaluation of mechanical and histological properties of cryopreserved human premolars under short-term preservation: A preliminary study

Background/purpose The aim of this study was to investigate whether storage of extracted teeth in transportation solution for 24 hours has a negative effect on the cell density and mechanical properties of thawed pulp tissue extracted from frozen intact teeth. Material and methods Human premolars were kept in transportation solution for 0 hours or 24 hours. For each transportation time, the tested teeth were divided into two experimental groups: teeth that had been frozen in a magnetic programmed freezer (PF, n = 5) and in a traditional freezer at -20°C (TF, n = 5). The tested teeth were then stored at -150°C for 7 days. After thawing, the extracted pulp was subjected to a histological examination and mechanical testing. Results Storage in transportation solution for 24 hours had no significant negative effects on the histological or mechanical properties of the pulp tissue extracted from the cryopreserved intact teeth. The elastic modulus of pulp from the teeth that had been frozen at -20°C was significantly higher (P <0.05) in samples that had been pre-stored in transportation solution for 24 hours. Conclusion This study demonstrated that exposure to transportation solution for 24 hours followed by storage in a programmed freezer did not negatively affect the cell density or the elastic modulus of the pulp tissue.