Chang Ya-Ting, Chen Gin
Division of Endodontics and Periodontics, Department of Oral Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
School of Dentistry, National Yang-Ming University, Taipei, Taiwan.
J Dent Sci. 2016 Mar;11(1):65-71. doi: 10.1016/j.jds.2014.03.007. Epub 2014 Jul 26.
BACKGROUND/PURPOSE: Atmospheric-pressure plasma is a new technology for biomedical applications. Utilization of an ionized gas (plasma) to achieve disinfection is an alternative sterilization technique that has become popular recently due to its safety, cost effectiveness, and superior performance to traditional methods. The purpose of this study was to evaluate the germicidal effectiveness of a low-temperature atmospheric-pressure plasma device by treating for different durations.
A novel low-temperature atmospheric-pressure plasma device was developed for this study. A suspension of (BCRC 10789) was standardized to 10 colony-forming units (CFUs)/mL, as confirmed by an optical spectrophotometer. was first transferred and spread on 70 sterile cover glasses measuring 18 mm. Each batch of 10 specimens was exposed to the low-temperature plasma device and treated for 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes, and 15 minutes; the specimen treated for 0 minute served as the control. The cover glasses containing plasma-treated bacteria were then immersed into 10 mL deionized distilled water and vibrated with an ultrasonic device to detach the residual fluid. Bacterial colonies were finally inoculated into Luria-Bertani agar plates and cultured at 37°C for 24 hours. The numbers of bacterial colonies were counted to evaluate the germicidal efficacy of the plasma device, and the results were expressed as CFUs. Meanwhile, field emission scanning electron microscopy was performed to observe the cell morphology of prior to and after plasma treatment.
Quantitative analysis of sterilization revealed a reduction in the number of bacterial colonies with time duration. When specimens were treated for 10 minutes, colonies of decreased from 10 CFUs to 10 CFUs. The sterilization -value (90% cell reduction) of experiments was 2 minutes.
The novel low-temperature atmospheric-pressure device was capable of achieving effective sterilization of within a 2-minute interval. Further studies are needed to validate complete inactivation, refine the laboratory-made low-temperature plasma device, and develop a new plasma-jet device, which will be superior to traditional sterilization methods and can be used in root canal environment. This novel sterilization method can also be used as a clinical reference tool.
背景/目的：大气压等离子体是一种用于生物医学应用的新技术。利用电离气体（等离子体）实现消毒是一种替代灭菌技术，由于其安全性、成本效益以及优于传统方法的性能，近年来已变得流行。本研究的目的是通过不同时长的处理来评估低温大气压等离子体装置的杀菌效果。
为该研究开发了一种新型低温大气压等离子体装置。通过光学分光光度计确认，将金黄色葡萄球菌（BCRC 10789）的悬浮液标准化至10个菌落形成单位（CFU）/毫升。首先将金黄色葡萄球菌转移并铺展在70个18毫米的无菌盖玻片上。每批10个标本暴露于低温等离子体装置并分别处理1分钟、2分钟、3分钟、5分钟、10分钟和15分钟；处理0分钟的标本作为对照。然后将含有经等离子体处理细菌的盖玻片浸入10毫升去离子蒸馏水中，并用超声装置振动以分离残留液体。最后将细菌菌落接种到Luria-Bertani琼脂平板上，并在37°C下培养24小时。计算细菌菌落数量以评估等离子体装置的杀菌效果，结果以CFU表示。同时，进行场发射扫描电子显微镜观察等离子体处理前后金黄色葡萄球菌的细胞形态。
杀菌的定量分析显示细菌菌落数量随时间减少。当标本处理10分钟时，金黄色葡萄球菌菌落从10 CFU降至10 CFU。实验的杀菌D值（90%细胞减少）为2分钟。
新型低温大气压装置能够在2分钟内有效杀灭金黄色葡萄球菌。需要进一步研究以验证完全灭活、改进实验室自制的低温等离子体装置并开发新的等离子体喷射装置，其将优于传统灭菌方法并可用于根管环境。这种新型灭菌方法也可作为临床参考工具。
