中文摘要：

目的研究聚酰亚胺共混改性聚甲基丙烯酸甲酯义齿基托树脂的力学性能。方法对自行合成的聚酰亚胺（添加质量百分比分别为0，0．4％，0．6％，0．8％，1％）与PMMA义齿基托树脂共混得到的改性基托树脂进行三点弯曲强度试验、断面形态扫描电镜观察和冷热循环试验。结果聚酰亚胺改性基托树脂抗弯强度在适当共混配比（0．6％）下可达（99．84±3．07）MPa，显著高于未改性树脂的抗弯强度（87．95±5．01）MPa，提高13．5％（Pl〈0．05）。经过冷热循环后其增强效果依然显著（P〈0．05）。结论添加一定量的聚酰亚胺共混改性PMMA基托树脂能获得理想的增强效果。

英文摘要：

Objective In this study, a self-synthesized polyimide was blended into PMMA-based denture materials. The mechanical properties and cyto-compatibility of this composition were tested to understand whether polyimide is an effective additive to strengthen denture base materials. Methods Testing of the flexural proper- ties and thermal cycling, scanning electron microscopy were used to characterize the composite denture material. Results Adding polyimide to 0.6% significantly increased flexural strength by 13.5% compared with the control group （P〈0.05）, and this reinforcement can also be observed after hydrothermal cycling. However, when polyimide content was further increased, flexural strength decreased due to particle aggregation. Conclusion Adding poly- imide in proper proportion （0.6%） could be a feasible method to strengthen PMMA-based denture material.