牙骨质再生对于正畸治疗至关重要。硬化蛋白由sost基因编码，是介导牙骨质改建的关键因子。前期发现硬化蛋白参与了正畸治疗后牙骨质再生，能抑制成牙骨质细胞增殖，促进凋亡，下调分化相关基因和蛋白。以硬化蛋白为靶点，通过针对sost基因的siRNA抑制硬化蛋白表达，从而促进牙骨质再生，能为解决正畸中相关问题提供新的思路。纳米颗粒作为运送siRNA的载体具有稳定性高、特异性强、协同性好的优点。因此，本研究拟在前期工作基础上，明确硬化蛋白在成牙骨质细胞增殖、分化中的作用及机制；合成并表征载sost-siRNA二氧化硅纳米颗粒，检测其对成牙骨质细胞和牙周膜干细胞增殖、分化的影响，对大鼠正畸模型中牙骨质再生的作用，分别从体外和体内层面分析应用纳米载体下调硬化蛋白表达从而促进牙骨质再生的可行性。

Cementum regeneration is important to orthodontic treatment.It has been known that sclerostin is involved in cementum regernation, which can inhibit proliferation and differentiation of cementoblasts.It is meaningful to orthodontic treatment by inhibiting sclerostin expression through siRNA. Nanoparticles are regarded as excellent carrier for siRNA delivery. In current research, we plan to investigate the effect and mechanism of sclerostin on cementoblasts; silica nanoparticles doped with sost-siRNA will be synthesized, and its effect on cementoblasts and PDL stem cells will be examined; then rat will be employed to check the effect on cementum regeneration. From the in vitro and in vivo experiments above, we will analyze the feasibility to make sclerostin as the target for cementum regeneration through inhibiting its expression by nanoparticles.