深冷冻保存对牙体组织生物力学性能影响的研究

Studies on the effect of cryopreservation on the biomechanical properties of human dental tissues

目的:探讨应用不同降温方法和冷冻保护液的深冷冻保存技术对人离体牙牙体组织生物力学性能影响。方法:收集新鲜拔除的人第一或第二前磨牙50颗,随机分为5组,分别使用含海藻糖的冷冻保护液中程序降温至-196℃、快速降温至-196℃,不含海藻糖的冷冻保护液中程序降温至-196℃、快速降温至-196℃,各组均冷冻保存一周,新鲜拔除牙齿为对照组。各组中5颗制成实性块状牙体组织标本,测试其压缩强度和弹性模量;另外5颗于颊面颈部制备Ⅴ类洞,树脂充填,经温度循环500周期后,2%亚甲基蓝溶液进行染料渗透实验,测量比较各组标本充填体边缘微渗漏情况。结果:与对照组比较,不同降温方法不同冷冻保护液深冷冻后,牙体组织压缩强度和弹性模量以及充填后微渗漏情况均无明显差异。结论:应用深冷冻技术保存牙齿,牙体组织生物力学性能及充填体边缘微渗漏无明显变化。

Objective： To explore the influences of different cooling methods and cryopreservation with different cryoprotectants on biomechanical performances of in vitro dental tissues. Methods： A total of 50 fresh teeth（ the first premolar or second premolar） were collected and divided into five groups. The tissues of four experimental groups were cooled to- 196 ℃ by programmed cooling method and rapid cooling method in cryoprotectant with or without trehalose,for 1 week cryostorage. And the fresh teeth of the control group were not given any treatment. Five teeth from each group were made into solid mass dental tissues,which were measured for compression strength and modulus of elasticity; another 5 teeth,in which Ⅴ-type dental cavities were made in the maxillofacial region and filled with resin,were given dye penetration test with 2% methylene blue solution after 500 temperature cycles. Micro leaking at the edge of dental filling materials in each group was measured and compared. Results： There were no significant differences between groups with different cooling methods and different cryoprotectants in dental compression strength,modulus of elasticity,and micro leaking at the edge of dental filling materials. Conclusions： There are no signicant differences in biomechanical properties of dental tissue and micro leaking at the edge of filling materials in cryopreservation for teeth preservation.