彻底清除种植体表面有机残留物对提高种植体周围炎治疗疗效具有重要意义。项目组前期研究表明种植体表面制备的TiO2涂层能有效光催化降解表面有机物，但存在性能难以调控、应用范围局限等不足。本项目提出构建可见光响应的光催化活性溶胶用于清除有机残留物的新思路。拟检测分析种植体表面有机残留物性质，设计制备TiO2-x/rGO/Alginate溶胶材料，通过光催化降解实验和理化表征，阐明材料组成结构对光催化活性的调控规律和有机残留物的降解反应机理。采用细胞学和兔股骨植入实验评价清除有机残留物对细胞功能和骨整合的恢复作用，进一步考察施加光催化清洁处理对比格犬种植体周围炎再生性治疗的促进作用。本项目研究将揭示种植体表面有机残留物的生物学影响，阐明光催化溶胶材料对有机残留物的光催化降解机理，形成用于种植体光催化清洁处理的材料制备技术和应用评价体系，为攻克种植体周围炎治疗难题提供新的解决思路。

In dental implantology, peri-implantitis is an increasing problem characterized by bacterial infection, suppuration and destruction of adjacent alveolar bone of implants with a prevalence of 20% in patients within 5-10 years. Biofilm formation on implant surface is the primary cause of peri-implantitis and the treatment of peri-implantitis is based on the removal of biofilm. However, it is hard to completely remove the organic residues of biofilm by conventional decontamination treatments, which would have side effects on the following treatments and re-osseointegration. Thus, it makes great sense to the treatment of peri-implantitis to completely remove organic residues from implant surfaces. Photocatalysis has been widely used in organic pollutant degradation and shows satisfying efficiency. Our previous research fabricated a black TiO2-x nanoceramic coating on titanium and proved it could effectively photo-oxidation of organics residues, but its disability for optimizing of photocatalytic activity, unsatisfied osseointegration and limited application could not meet clinical demands. On this basis, this project proposes a novel strategy to address these issues. We aim to fabricate a novel kind of brushable TiO2-based composite sol with high visible-light photocatalytic activity for photocatalytic removal of organic residues on implant surface. In this project, contaminated failed implants were collected and the organic residues after conventional debridements will be detected and analyzed to obtain the composition and content information by immunofluorescence staining, ELISA kit and ToF-SIMS. Then, we are going to design and fabricate a kind of TiO2-x/rGO/Alginate composite sol (TiO2-x:reduced titania, rGO: reduced graphene oxide) and investigate the structure and physicochemical properties by TEM, XPS, FTIR and UV-vis detections. By photocatalytic degradation experiments of RhB, LPS, BSA, et al., the photocatalytic properties will be thoroughly evaluated and the relationship between material structure and photodegradation activity can be revealed. Furthermore, the interface reaction mechanism and degradation products of representative organics will be revealed by PL, EPR, In-situ Raman and In-situ FTIR. The efficiency and factors of photocatalytic removing treatment on contaminated titanium disks and failed implants will also be investigated. Based on this, the differences of fibrin adsorption, MC3T3 and RAW264.7 cells responses were compared among fresh SLA titanium samples, contaminated and photocatalytic-cleaning-treated ones. In vivo implant experiment will also be carried out in rabbit femurs and the Micro-CT and histology analysis will be applied to compare the osseointegration ability of fresh SLA samples and contaminated ones before and after photocatalytic cleaning. Furthermore, the ligature-induced peri-implantitis model in beagles was established. Then surgical regenerative therapy will be carried out to find the differences between control group (conventional decontamination: carbon curettes and air abrasive with glycine) and experimental group (conventional decontamination+photocatalytic cleaning). After 3 and 6 months, clinical indexes, radiography and histology results will be investigated to evaluate the improvement of clinical outcomes and re-osseointegration. This project will reveal the characteristics and biological effects of organic residues on implant surfaces. The photodegradation mechanism of the novel composite sol towards organic residues will also be elucidated. Afterwards, a systematic material preparation and evaluation techniques for photocatalytic decontamination of dental implant surfaces can be established. Based on this project, it is promising to develop an efficient strategy for deep decontamination of implant surfaces, which will make a breakthrough in the treatment of peri-implantitis.