气流分散聚甲基丙烯酸甲酯/二氧化硅纳米义齿树脂的生物安全性*

背景：前期实验已经成功制备甲基丙烯酸甲酯/二氧化硅（PMMA/SiO2）纳米复合材料，并证实其有良好的机械性能。 目的：进一步评价气流分散PMMA/SiO2纳米义齿树脂的生物安全性，为今后开展临床实验提供研究依据。 设计、时间及地点：随机分组设计，对比观察实验，于2006-09/2007-10在天津医科大学基础医学院微生物实验室及公共卫生学院毒理实验室完成。 材料：采用气流分散法，以纳米SiO2与甲基丙烯酸甲酯复合制备PMMA/SiO2纳米义齿树脂。 方法：参照IS07405-1997(E)标准，对气流分散PMMA/SiO2纳米义齿树脂材料进行细胞毒性实验、溶血实验、急性全身毒性实验、口腔黏膜刺激实验以及皮肤致敏实验，初步评价其生物安全性。 主要观察指标：MTT法测定细胞相对增殖率并评级；溶血实验测定溶血率；急性全身毒性实验观察小鼠一般状态及体质量变化；口腔黏膜刺激实验观察试件接触部位组织切片；皮肤致敏实验观察致敏区红斑及水肿反应。 结果：细胞毒性实验表明PMMA/SiO2纳米材料的细胞毒性为1级，显示极轻微的细胞毒性；溶血实验显示其溶血率小于5%；急性全身毒性实验和口腔黏膜刺激实验显示材料实际无毒、无明显黏膜刺激性；皮肤致敏实验显示无明显致敏性。 结论：气流分散PMMA/SiO2纳米义齿树脂具有良好的生物安全性。

Biological safety of polymethyl methacrylate/SiO2 denture nanocomposites by air-flow dispersion

BACKGROUND: The polymethyl methacrylate (PMMA)/SiO2 denture nanocomposites have been successfully prepared with good mechanical strength. OBJECTIVE: To evaluate the biological safety of PMMA/SiO2 denture nanocomposites by air-flow dispersion, further provide evidences for clinic study. DESIGN, TIME AND SETTING: A randomized control experiment was conducted in Microbiology Laboratory of Basic Medical College and Toxicology Laboratory of Public Health College, Tianjin Medical University from September 2006 to October 2007. MATERIALS: The PMMA/SiO2 denture nanocomposites were prepared by air-flow dispersion. METHODS: Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucosa membrane irritation test and skin sensitization test were investigated according to standard of ISO 7405-1997(E). MAIN OUTCOME MEASURES: Relative growth rate and cytotoxicity grade was detected with MTT method. Hemolysis rate was also detected. General toxicity reaction was determined by the general condition and body mass change. Mucous membrane irritation reaction and skin sensitivity reaction were observed. RESULTS: The cytotoxicity grade of PMMA/SiO2 denture nanocomposites was scored as 1,which indicated slight cytotoxicity. Hemolysis rate was less than 5%. Acute systemic toxicity and mucous membrane irritation reaction test showed there was no irritant reaction for mucosa membrane. Skin sensitivity test displayed no skin sensitivity. CONCLUSION: The PMMA/SiO2 denture nanocomposites by air-flow dispersion have good biological safety.