Abstract: Objective    To detect the disinfection effect of different concentrations of slightly acidic hypochlorite water（SAHW）on dental unit waterlines（DUWLs）. Methods    Totally 32 dental chair unit（DCU） were randomly divided into a control group and three test groups （8 DCU in each group）. DUWLs were supplied by sterile distilled water（DW）for 7 consecutive days in the control group. SAHW with effective chlorine content of 8-12 mg/L，18-22 mg/L and 28-32 mg/L was used for 7 consecutive days in test group 1，2 and 3，respectively. The water samples of high-speed handpiece and three gun were collected for bacteria culture and colony count，once a day，seven times in a row. At the beginning of the 8th day of intervention，DW was used to supply water to DUWLs for 7 consecutive days in the test groups. Water samples were cultured and counted，once a day，for 7 consecutive times. SPSS20.0 software was used for statistical analysis. Results　Compared with the basic water sample，the colony count of high-speed handpiece and three gun water samples in test group 1，2 and 3 decreased significantly（P < 0.05）on the first day after SAHW disinfection. On the second day after SAHW disinfection，the colony count of high-speed handpiece and three gun water samples in test group 3 was lower than the upper limit of qualified water samples（100 CFU/mL）. Three days after SAHW disinfection，the colony count of test group 3 was 0 CFU/mL，the colony count of test group 1 and test group 2 were significantly lower than 100 CFU/mL. In the three test groups，the colony count of DCU high-speed handpiece and three gun water samples was maintained within 100 CFU/mL for 1-2 days after DW water supply，and there was no statistical difference among the three test groups（P > 0.05）. After 3-7 days，the colony count of high-speed handpiece and three gun water samples in the test groups was continuously increasing （149～1014 CFU/mL），and there was statistical significance in the counts at different time points in each test group（P > 0.05），and all of them were statistically higher than the upper limit of qualified water sample（P < 0.05）. Conclusion    Compared with low concentration，SAHW with high effective chlorine content has higher disinfection efficiency. SAHW with the lower effective chlorine content of 8-12 mg/L continuously acts on the internal environment of DUWLs，which can effectively control the colony count and has obvious disinfection effect.

Key words: dental unit waterlines, DUWLs；slightly acidic hypochlorite water, SAHW；disinfection

摘要： 目的　检测不同浓度微酸性次氯酸水（slightly acidic hypochlorite water，SAHW）应用于口腔综合治疗台水路（dental unit waterlines，DUWLs）的消毒效果。方法    选取32台口腔综合治疗台（dental chair unit，DCU），随机均分为4组（1个对照组和3个实验组，每组8台DCU）。首先，采集高速手机和三用枪基础水样行细菌培养、菌落计数；然后，实验组分别用有效氯含量8 ~ 12 mg/L（实验1组）、18 ~ 22 mg/L（实验2组）、28 ~ 32 mg/L（实验3组）的SAHW供水DUWLs，连续7 d采集高速手机和三用枪水样行细菌培养、菌落计数。第8 d始改用无菌蒸馏水（distilled water，DW）供水DUWLs后采集水样菌落培养计数；对照组用DW替代消毒水，同样程序流动冲洗DUWLs后收集高速手机和三用枪水样菌培养后菌落计数。数据采用SPSS 20.0软件进行统计分析。结果    与基础水样比较，SAHW消毒1 d，3个实验组的高速手机和三用枪水样菌落计数均显著下降（P < 0.05）；SAHW消毒2 d，实验3组高速手机和三用枪水样菌落计数均小于消毒合格水样上限值（100 CFU/mL）；SAHW消毒3 d开始，实验3组菌落计数为0 CFU/mL，实验1组和2组菌落计数均显著小于100 CFU/mL。更换为DW供水后1 ~ 2 d，3个实验组的高速手机和三用枪水样菌落计数维持小于100 CFU/mL，组间差异无统计学意义（P > 0.05）；3 ~ 7 d，3个实验组的高速手机和三用枪水样菌落计数持续增加（149 ~ 1014 CFU/mL），实验1、2、3组的组内不同时间点检测数据比较差异均有统计学意义（均P < 0.05），且均明显大于合格水样上限值（P < 0.05）。结论    高有效氯含量较低有效氯含量的SAHW消毒效果更稳定；低有效氯含量8 ~ 12 mg/L的SAHW持续作用于DUWLs内环境亦可有效控制菌落计数，消毒效果明显。

关键词: 口腔综合治疗台水路, 微酸性次氯酸水, 消毒