ABSTRACT The reduction of microbial contamination in dental unit waterlines (DUWLs) appears to be necessary because of a potential risk of infections in immunocompromised patients and medical staff, which are regularly exposed to water and aerosols generated from DUWLs. In the present study, the qualitative and quantitative microbial contamination of water in DUWLs were determined and the conventional biomedical diagnostic tests were applied to identify microorganisms. A 3-level, 2-factor central composite design was utilized to investigate the effects of chief operating parameters and optimize ozone disinfection conditions. Also, the activity of three disinfectant (ozone, NaOCl, and peracetic acid) in microbial decontamination of DUWLs were compared. The results indicated that Microbacterium laevaniformans were the most prevalent genera (21%) among both Gram-negative and positive species in all samples. Regression analysis illustrated the good fit of the experimental data to the predicted model with R2 and R2adj correlation coefficients of 0.988 and 0.980, respectively. Moreover, under the optimal circumstances (Ozone concentration = 1.2 ppm and reaction time = 13.5 min) the disinfection efficiency was 97.52%. The results also revealed that ozone was effective disinfectant to reduce prevalent genera (with the removal of 93.75%, 92.57% and 96.15% of Pseudomonas aeruginosa, Microbacterium ‎laevaniformans, and Alcaligenes faecalis, respectively) and already formed biofilms under optimum conditions. Based on achieved results, ozone was highly effective on microbial decontamination compared to peracetic acid and NaOCl disinfectant and can be used for disinfection of DUWLs.

中文翻译：

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使用响应面法优化牙科治疗台水线消毒的臭氧化过程

摘要 减少牙科综合治疗台水线 (DUWL) 中的微生物污染似乎是必要的，因为免疫功能低下的患者和医务人员有潜在的感染风险，他们经常接触水和 DUWL 产生的气溶胶。在本研究中，确定了 DUWL 中水的定性和定量微生物污染，并应用传统的生物医学诊断测试来识别微生物。采用 3 级、2 因子中心复合设计来研究主要操作参数的影响并优化臭氧消毒条件。此外，还比较了三种消毒剂（臭氧、NaOCl 和过氧乙酸）在 DUWL 的微生物净化中的活性。结果表明，在所有样品的革兰氏阴性和阳性物种中，微杆菌属 (Microbacterium laevaniformans) 是最普遍的属 (21%)。回归分析表明实验数据与预测模型的良好拟合，R2 和 R2adj 相关系数分别为 0.988 和 0.980。此外，在最佳情况下（臭氧浓度 = 1.2 ppm，反应时间 = 13.5 分钟），消毒效率为 97.52%。结果还表明，臭氧是减少流行属的有效消毒剂（分别去除了 93.75%、92.57% 和 96.15% 的铜绿假单胞菌、微杆菌和粪产碱菌）并且在最佳条件下已经形成了生物膜。根据取得的成果，