Abstract: Objective　To develop a new type of non-abrasive toothpaste and evaluate its effect on the surface properties of polymethyl methacrylat（PMMA）resin. Methods　Remove the abrasive and adjust the ratio of surfactant and wetting agent to evaluate the characteristics of the new toothpaste；choose the new toothpaste with the best characteristics（new toothpaste group A and new toothpaste group B），the market toothpaste（market toothpaste group A and market toothpaste group B），market effervescent tablet（market effervescent tablet group）and distilled water （control group） to clean the PMMA resin sheet；compare the absorbance（OD）and roughness（Ra）values of the surface of the PMMA resin sheet before and after cleaning in each group；evaluate the cleaning effect and wear level of various cleaning agents on the surface of PMMA resin. Results　Among the 10 new toothpastes，No. 2 and No. 6 were better，their pH values were 7.18 and 7.22，respectively，and they were used in subsequent studies. （1）Cleaning effect：there was no significant change in the plaque red staining or OD value of PMMA resin sheet before and after cleaning in the control group，and the difference was not statistically significant（P > 0.05）. The plaque red staining degree of PMMA resin sheet in the remaining groups was significantly lower after cleaning than that before cleaning，and the OD value was also significantly reduced，the difference being statistically significant（P < 0.05）；especially in the market effervescent tablet group，new toothpaste group A and new toothpaste group B，the cleaning effect was the most significant.（2）Abrasion level：the stereo microscope showed that the surface of the PMMA resin sheet in the control group was smooth and there were no scratches after cleaning. In the market toothpaste group A and the market toothpaste group B there were a large number of deep scratches，and the Ra value also increased significantly，and the differences were statistically significant（both P < 0.05）. The PMMA resin sheet in the market effervescent tablet group，the new toothpaste group A and the new toothpaste group B showed only slight and shallow scratches，and the Ra value increased slightly，but the difference was not statistically significant（P > 0.05）. Conclusion　The new non-abrasive toothpaste can effectively remove plaque and soft dirt while reducing scratches on the surface of the denture，and can become a clinical toothpaste for denture cleaning.

Key words: toothpaste；polymethyl methacrylate, PMMA；abrasive

摘要： 目的　研制新型无磨料牙膏，并评估其对聚甲基丙烯酸甲酯（polymethyl methacrylat，PMMA）树脂表面性能的影响。方法　在新型牙膏中去除磨料并调整表面活性剂和湿润剂的比例，对10种新型牙膏的性状进行评估；选择较佳性状的2种新型牙膏（新型牙膏A组和新型牙膏B组）与市面牙膏（市面牙膏A组和市面牙膏B组）、市面泡腾片（市面泡腾片组）及蒸馏水（对照组）对PMMA树脂片进行清洁处理，比较各组清洁前后PMMA树脂片表面光密度（OD）值及粗糙度（Ra）值，评估各类清洁剂对PMMA树脂表面清洁效果及磨损水平。结果　10种新型牙膏中2号（新型牙膏A组）和6号（新型牙膏B组）具有较佳的性状，其pH值分别为7.18和7.22，并用于后续研究。（1）清洁效果：对照组清洁处理前后PMMA树脂片菌斑红染及OD值基本无明显变化，差异无统计学意义（P > 0.05），其余各组清洁处理后的PMMA树脂片菌斑红染程度较清洁处理前明显降低，OD值也显著下降，差异有统计学意义（均P < 0.05），尤其以市面泡腾片组、新型牙膏A组和新型牙膏B组清洁效果最为显著。（2）磨损水平：体视显微镜观察发现，清洁处理后，对照组PMMA树脂片表面光滑无划痕；市面牙膏A组和市面牙膏B组PMMA树脂片表面划痕较深且划痕数量较多，Ra值也明显增大，差异均有统计学意义（均P < 0.05）；市面泡腾片组、新型牙膏A组和新型牙膏B组PMMA树脂片表面仅出现轻微细小浅划痕，Ra值略微升高，但其差异均无统计学意义（均P > 0.05）。结论　新型无磨料牙膏在有效清除菌斑软垢的同时可减少PMMA树脂表面划痕，可成为临床义齿清洁牙膏。

关键词: 牙膏, 聚甲基丙烯酸甲酯, 磨料