目的

评价口腔综合治疗台独立水源水路经525 mg/L 次氯酸钠消毒前、后水样微生物种类和总菌落数的差异。

方法

分别选择10 台独立水源口腔综合治疗台为实验组和对照组。 采集水路经525 mg/L 次氯酸钠消毒前、后治疗台三用枪水样，计算总菌落数，定性检测水样中微生物种类与条件致病菌。利用SPSS 10.0 统计软件进行两样本t 检验、配对t 检验和单因素方差分析，α=0.05。

结果

（1）525 mg/L 次氯酸钠消毒前、后口腔综合治疗台总菌落数几何均值分别为2.23 × 10³ 和0 CFU/ml（P ＜0.05），差异有统计学意义；（2）消毒前、后微生物种类分别为8 种和3 种；消毒前检测出铜绿假单胞菌（检出率为36%），未检出大肠埃希氏菌和嗜肺军团菌；消毒后均未检出。

结论

口腔综合治疗台水路存在微生物污染，并且包含条件致病菌铜绿假单胞菌，存在引起医患医院感染的潜在风险。 525 mg/L 次氯酸钠消毒剂对口腔综合治疗台水路具有良好消毒效果，能有效杀灭水样中微生物，可用于独立水源口腔综合治疗台水路的消毒处理。

Objective

To evaluate the difference of the species and quantity of microorganisms in dental unit water lines （DUWL） before and after disinfecting with sodium hypochlorite solution.

Methods

The water supplied with 20 separate sources were collected and divided into two experimental groups， each comprising ten DUWL. The microorganisms were quantified with nutrient agar after incubated for 48 h， recorded as colony forming unit （CFU/ml）. The species of microorganisms were studied. Pseudomonades， Legionella and E.coli were determined with National Standard Methods. The sodium hypochlorite at concentration of 525 mg/L was used in this study for disinfection of DUWL. The data were analyzed by ＂two-sample t-test for independent samples＂， ＂paired t-test for independent samples＂ and ＂one-way ANOVA＂ with SPSS 10.0 software， α=0.05.

Results

（1）The number of bacteria in water at the baseline was 2.23×10³ CFU/ml before disinfection with sodium hypochlorite solution， whereas it was 0 CFU/ml（P ＜0.05） after disinfection. （2）Eight species of bacteria were identified from the separate water，and three species were identified after disinfection. Before disinfection Pseudomonas were positive in 7 samples （out of 20）（35%） of the separate water， and E.coli and Legionella were not found in water. The three opportunistic pathogens were not detected after disinfection.

Conclusions

This study confirmed that DUWLS has been contaminated heavily with a number of microbes，including some opportunistic pathogens like Pseudomonas. The high concentration of microbes in DUWL brings high risk of cross infection to both dental professionals and patients. Sodium hypochlorite at the concentration of 525 mg/L may be used as a disinfection solution for DUWL infection control contributing its satisfying disinfection effect.