甘氨酸引导羧甲基壳聚糖/无定形磷酸钙再矿化脱矿牙釉质表面的研究

Study on the remineralization of demineralized enamel surfaces with glycine⁃guided carboxymethyl chitosan/amorphous calcium phosphate

目的探讨甘氨酸引导羧甲基壳聚糖(carboxymethyl chitosan,CMC)/无定形磷酸钙(amorphous calci⁃um phosphate,ACP)对脱矿牙釉质表面的再矿化作用。方法制备不同阶段再矿化液:①反应态CMC/ACP(NaClO处理的CMC/ACP),②反应态CMC/ACP+甘氨酸;透射电子显微镜检测再矿化液颗粒形貌。选取20颗阻生齿制成釉质切片并脱矿,随机分为A、B两组,将反应态CMC/ACP涂抹于A组牙釉质表面;将加入甘氨酸的反应态CMC/ACP再矿化液涂抹于B组。扫描电子显微镜检测再矿化前后牙釉质表面形貌,纳米压痕实验检测牙釉质表面机械强度(包括压刻深度、硬度和弹性模量)。结果透射电镜下观察,反应态CMC/ACP再矿化液颗粒光滑,粒径增加至100~300 nm。反应态CMC/ACP加入甘氨酸后颗粒呈现出线状有序排列,15 min后溶液内形成了微晶体,晶体长度约为5~15μm。A组再矿化表现为颗粒状,且为杂乱的非均质再矿化层,B组脱矿牙釉质表面形成了较为均质的晶体形貌且排列有序,与天然牙釉质晶体形貌类似。B组再矿化后压刻深度小于A组,也最接近天然牙釉质;B组再矿化后的表面硬度和弹性模量与天然牙釉质差异无统计学意义。结论通过在NaClO处理的CMC/ACP纳米颗粒中加入甘氨酸而形成的快速牙釉质龋再矿化模型,能够在釉质表面形成定向有序且快速的再矿化,再矿化的牙釉质表面的机械强度与天然牙釉质相近。

Objective To explore effect on the remineralization of demineralized enamel surfaces with glycine⁃guid⁃ed carboxymethyl chitosan(CMC)/amorphous calcium phosphate(ACP).Methods Remineralized solultion at different stages were prepared:①reactive CMC/ACP(CMC/ACP nanoparticles treated with NaClO),②reactive CMC/ACP+gly⁃cine;transmission electron microscopy was used to detect the morphology of the remineralized solution particles.Twenty teeth were randomly divided into two groups:group A and group B.Reactive CMC/ACP was applied to the enamel sur⁃face of group A and group B was treated with reactive CMC/ACP remineralization solution containing glycine.Scanning electron microscopy was used to detect the enamel surface morphology before and after remineralization,and nanoinden⁃tation was used to detect the mechanical strength(including nanoindentation depth,hardness and elastic modulus)of the enamel surface.Results Under a transmission electron microscope,the particles in the reactive CMC/ACP remin⁃eralization solution were smooth,and the increase in particle size was approximately 100⁃300 nm.After the addition of glycine,the particles in the reactive CMC/ACP remineralization solution particles showed a linear ordered arrangement,and microcrystals were formed in the solution 15 min later,with a crystal length of approximately 5⁃15μm.Remineral⁃ization in group A was granular and heterogeneous.In group B,the crystal morphology of the demineralized enamel was homogeneous and ordered,similar to that of natural enamel.The nanoindentation depth of group B after remineralization was smaller than that of group A,and it was closest to that of natural enamel,there was no significant difference be⁃tween group B and natural enamel in terms of the hardness and elastic modulus of the enamel surface after remineraliza⁃tion.Conclusion CMC/ACP nanoparticles treated with NaClO can rapidly and specifically form directional and or⁃dered remineralization on the enamel surface of a model of glycine⁃guided rapid remineralization of enamel caries.The surface structure of remineralized enamel is similar to that of natural enamel in terms of nanoindentation depth,hard⁃ness and elastic modulus.