OXYGEN PLASMA TREATMENT FOR STERILIZATION IN DENTISTRY

高压灭菌器作为一种有效的器械和材料消毒方法，在牙科领域得到了广泛的应用。碳钢仪器的腐蚀和仪器表面残留的分解细菌一直是高压灭菌器的问题。本研究的目的是研究氧气等离子体反应器作为牙科消毒器的特性。使用的等离子体反应器为PR-31型(Yamato Science Co.Ltd.)。采用电容耦合的方法对玻璃腔施加13.56 MHz的高频电场。氧流量为50ml/min~100ml/min。用铁康铜热电偶(直径0.08 mm)测量插入Pla SMA的玻璃管(外径2.00 mm，内径0.95 mm)的内部温度。以等离子金属板(5*20*0.5 mm)为试件，温度随输出功率和施加时间的增加而升高。将全唾液(约10000至1000000CFU)放置在标本上并干燥30分钟。通过脑心输液中的培养标本来评估其效果。当采用300W(10min)的等离子体处理时，25个试件全部为阴性培养。对新的碳钢毛刺进行等离子体、高压灭菌或干热灭菌处理。扫描电子显微镜观察表明，等离子体处理后的毛刺表面最干净，氧等离子体处理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.