中文摘要：

目的：评价5种不同义齿清洁方式对活动义齿树脂基托表面形貌的影响。方法制作35个热凝树脂（PMMA）试样（15 mm×10 mm×2 mm），将试样打磨、抛光，根据义齿不同清洁方式将试样随机分为五组：对照组A组，蒸馏水浸泡；实验组B、C、D、E组，B组牙刷＋蒸馏水刷洗清洁2 min，C组牙刷＋牙膏刷洗清洁2 min，D组Polident清洁片溶液浸泡5 min，E组Polident清洁片浸泡5 min＋牙刷刷洗清洁2 min，重复处理180个循环。粗糙度仪测试试样处理前后表面粗糙度值（Ra），扫描电子显微镜（SEM）观察试样处理前后表面结构。结果①A组和D组处理前后试样表面Ra值比较，差异无统计学意义（P＞0.05），B组、C组和E组试样处理前后表面Ra值，差异均有统计学意义（P＜0.05），C组Ra值增加最大。试样处理后各组表面粗糙度值不全相同，与A组试样Ra值比较，D组试样Ra值增加，差异无统计学意义（P＞0.05）；B组与E组Ra值比较，差异无统计学意义（P＞0.05），其他各组两两之间Ra值差异均有统计学意义（P＜0.05）。②不同清洁方式处理前，扫描电子显微镜（SEM）下观察试样表面光滑无划痕。不同义齿清洁方式处理后， A组、D组试样表面光滑无划痕，B组、E组试样表面可见方向一致的连续浅刷痕，C组试样表面可见方向一致的连续深刷痕。结论清洁片清洁方式对热凝表面形貌影响最小；牙刷＋蒸馏水、清洁片＋牙刷清洁方式对热凝树脂表面形貌影响较小；牙刷＋牙膏清洁方式可明显改变热凝树脂表面形貌。

英文摘要：

Objectives This in vitro study aimed to evaluated the effect of five denture cleaning methods on the surface of the removeable partial denture that simulated 180 days of cleaning.Methods thirty-five heat-polymerized acrylic resin （HPAR） were prepared and polished. According to different ways of treatment, the samples were randomly divided into 5 groups. The black control group A was immersed in distilled water. B,C,D and E groups were experimental groups as follows. Group B was brushed with distilled water. Group C was brushed with dentifrice. Group D was immersed in Polident solution. Group E was brushed with Polident solution after immersed in Polident solution , which simulated 180 days of cleaning. A surface analyzer was used to measure the roughness （Ra） before and after treatment. Scanning electron microscopy were used to observe scratch on the samples before and after treatment.Results ①The mean roughness of group A and group D were no statistically difference after treatment （P〉0.05）. B,C and E groups were significant differences after treatment （P〈0.01）. The highest mean was obtained for group C. The mean roughness of the five groups were not all the same after different ways of treatment. Compared with group A （control group）, the mean roughness of group D was slightly increased, there was no statistically difference （P〉0.05）. There were significant differences between group B and group E（P〉0.05）.②The SEM observation of A and D groups of HPAR sample surface had not obvious scratch after different treatment, The surface of B and E groups had slight scratch. The surface of C group was obviously scratched compared with per-treatment.Conclusions The way of immersing in Polident solution would slightly increase the surface roughness but no scratch. The way of brushing with distilled water or Polident solution would slightly increase the surface roughness and would slightly produce scratch. The way of brushing with dentifrice would obviously increase the surface roughne