Abstract:

Objective    To test the mechanical properties of freeze-dried tooth and its biocompatibility with SHED， and explore the feasibility of freeze-dried tooth as scaffold materials for tooth tissue regeneration. Methods    The supernumerary teeth and the orthodontic extracted teeth with single root were collected clinically.Then the freeze-dried teeth were manufactured after the process of tooth preparation，derosination and deproteinization， deep freezing， freeze drying， and sterilization. The surface morphology and microstructure of the freeze-dried teeth were detected under scanning electron microscope （SEM）， and their mechanical properties were examined by microhardness test. The SHED co-cultured with freeze-dried teeth were observed to evaluate the cellular adhesion， growth and proliferation by SEM， Hoceststaining， and MTT methods. Results    After freeze drying， the teeth roots and root canals presented the visible cleaner surface， and still remained the original microstructure. The Vickers hardness of the freeze-dried teeth had no statistical difference from normal control teeth. At the same time， SHED co-cultured with freeze-dried teeth had a better cellular adhesion and growth than the control，and there is significant difference on the cell number at 18 h. Moreover， the freeze-dried teeth had smaller influence on SHED proliferation compared with control. Conclusion    The freeze-dried teeth not only remain the original microstructure and mechanical properties， but also have better cellular compatibility with SHED. So the freeze-dried tooth can act as a kind of scaffold material for tooth tissue regeneration.

Key words: freeze-dried teeth； stem cells derived from human exfoliated deciduous teeth, SHED； biological properties

摘要：

目的    检测和分析冻干牙的机械性能以及生物相容性，探讨其作为牙再生支架材料的可行性。方法    临床收集单根的多生牙及正畸拔除牙，通过牙体预备、脱脂、去蛋白、深冷冻、冷冻干燥、消毒灭菌等过程制备冻干牙；首先利用扫描电镜观察其表面形态和微观结构，显微硬度测试其机械性能；进而将人乳牙牙髓干细胞（SHED）和冻干牙片进行复合培养，电镜观察细胞形态变化，Hoechst染色后观察SHED细胞数目的变化，四甲基偶氮唑盐（MTT）比色法检测冻干牙对SHED增殖活性的影响。结果    经过冻干处理的牙根表面及髓腔清洁，并保持完整的牙齿微观结构；冻干牙的显微硬度和正常对照牙无显著差别；冻干牙片表面SHED黏附生长情况要优于正常牙片，此外活细胞数量与正常对照在培养18 h时差异有统计学意义（P < 0.05）；而冻干牙对SHED增殖活性的影响低于与正常对照。结论    制备的冻干牙不仅保持原有的形态结构和机械性能，并且与具有良好的生物相容性，是一种理想的牙再生支架材料。

关键词: 冻干牙, 乳牙牙髓干细胞, 生物学性能