OXYGEN PLASMA TREATMENT FOR STERILIZATION IN DENTISTRY

高压蒸汽灭菌器作为一种有效的器械和材料灭菌方法，已广泛应用于口腔医学领域。碳钢器械的腐蚀和器械表面残留的分解细菌物质一直是高压灭菌器的问题。本研究旨在探讨氧电浆反应器作为牙科灭菌器的特性。使用的等离子体反应器是PR-31型（YAMATO Sci. Co. Ltd）.采用电容耦合的方法，在玻璃腔体中施加13.56MHz的高频电场。氧流量为50 ~ 100 ml/min，用直径为0.08mm的铁-康铜热电偶测量插入塑料中的玻璃管（外径为2.00mm，内径为0.95mm）的内部温度。温度根据等离子体施加的输出功率和持续时间而升高。使用金属板（5*20*0.5mm）作为测试样本。将全唾液（约10000至1000000 CFU）置于样本上并干燥30分钟。用脑心浸液肉汤培养标本评价其作用。采用300 W（10 min）的等离子体处理25个标本，均为阴性。对新碳钢布尔斯车针分别进行等离子体处理、高压灭菌或干热灭菌。通过扫描电镜观察，氧等离子体处理后的布尔斯表面清洁度最好，说明氧等离子体处理后的牙钻具有作为牙科消毒剂的可能性。

The autoclave has been widely used in dentistry as an effective method to sterilize instruments and materials. Corrosion of carbon steel instruments and the decomposed bacterial substances remaining on the surface of the instruments have been the problem with the autoclave. The purpose of this study was to investigate the characteristics of an oxygen plasma reactor as the dental sterilizer. The plasma reactor used was type PR-31 (YAMATO Sci.Co.Ltd) . High frequency electric field of 13.56MHz was applied to the glass cham ber by capacitance coupling. Oxygen flow in the chamber was 50ml/min to 100ml/min.Internal temperature of a glass tube (outer diameter : 2.00mm, internal diameter : 0.95mm) inserted into the pla sma was measured by the iron-constantan thermocouple(diameter : 0.08mm) . The temperature increased in accordance with the out put power and duration of the application of the plasmaMetal plates (5*20*0.5mm) were u sed as the test specimens. Whole saliva (circa 10000 to 1000000CFU) was place d on the specimen and dried for 30min. The effect was estimated by the cult ured specimens in the brain heart infusion broth. When the plasma treatment of 300W (10min) was applied, all of the 25 specimens resulted in negative culture.New carbon steel burs were treated by plasma, or autoclave sterilization or dry heat sterilization. Obsevation of the surfaces of these burs under a scanning electron microscope revealed that plasma treatment produced the cleannest surface.In conclusion, the oxygen plasma treatment has possibility to be used as a dental sterilizer.