聚乳酸复合物预成乳牙根管桩的体外降解性研究

Degradation of Polylactic Acid/hydroxyapatite Composite Primary Teeth Post in Vitro

目的:评估聚乳酸/羟基磷灰石(PLA/HA)复合物的体外降解性。方法:本实验参照我国医疗器械生物学评价标准,将PLA/HA和PLA两种材料分别浸泡到磷酸盐缓冲液(PBS液)和蒸馏水中,分别在不同的时间点对试件进行一系列体外实验评价PLA/HA的体外降解性。结果:肉眼观察试件颜色逐渐变白且出现微裂纹;SEM显示:随降解时间延长,HA颗粒逐渐变小,PLA出现孔隙且大小不一;PLA/HA和PLA分子量逐渐较小;弹性模量和弯曲强度均有所衰减;PLA/HA和PLA中降解液的pH值均逐渐降低,且PLA比PLA/HA要下降的快。结论:PLA/HA具有一定的降解性能,在观察的10个月内,其力学强度能够维持乳牙的咬合力。

Objective：To evaluate the degradation in vitro of polylactic acid/hydroxyapatite（PLA/HA）compositesprimary teeth post.Methods：According to the Chinese standard for biological evaluation of medical devices,the PLA/HA and PLA were immersed in phosphate buffer liquid（PBS）and distilled water,and a series of tests were performed with specimens in vitro at different time points respectively to evaluate the degradation in vitro of PLA/HA.Results：Macroscopic observation showed that the specimen color turned to white gradually and appeared micro cracks.The SEM results showed that the HA particles became smaller and PLA appeared sizes pore with the extension of degradation time.The molecular weight of PLA/HA and PLA decreased gradually and its elastic modulus and bending strength attenuated.The pH values of PLA/HA and PLA degradation solutions reduced gradually and that of PLA was falling faster than that of PLA/HA.Conclusion：The PLA/HA has a certain degradation performance,and its mechanical strength can keep primary teeth bite force in the ten months of observation.