THE EFFECT OF THE STERILIZATION OF THE AIR-TURBINE HANDPIECES

1.高压灭菌对牙科机头轴承的影响在牙科器械中，牙科机头(THP)的消毒有特殊的困难。困难在于其复杂而精细的机械结构，在消毒周期中额外购买套装以填补空缺的成本，以及通过高压灭菌程序缩短其使用寿命。本研究的目的是为了阐明8个THPS的精细机械结构，并评价重复高压灭菌(121ﾟC，15min)后THPS特性的变化。结果如下：1)每个Dearing由一个外环、一个内环、七个或八个球和一个支承轴承球(保持器)组成。两种固位体在形状和材质上有很大差异。2)显微镜观察显示，所有…的支承部表面都存在一些物质或许多小孔，并有一些磨损或粘着变色。Soeme THPS中的润滑油较多。3)通过采集转子转速与反复高压灭菌过程的关系，阐明高压灭菌对轴承机械特性的影响。用麦克风采集并记录在磁带上，用快速傅立叶变换(FFT)程序在存储程序的计算机上对其功率谱进行分析。经100次高压灭菌后，所有THPS的最大峰值频率(MPF)和相对功率强度(MPF)的频率和相对功率强度与初始条件下的不同。在一些THPS中，观察到MPF的变化不依赖于转子转速，这些变化表明THPS的内部结构存在一定的变形，特别是在保持器中，转子的声音是评估其力学状况的有用线索。氧等离子体处理的影响碳钢器械的腐蚀和残留在器械表面的分解细菌物质一直是高压灭菌器的问题。本研究的目的是研究氧等离子体反应器(PR-31 Yamato Sci)的效果。用300W的功率对全唾液(约10^4~10^6 CFU)污染的标本进行25种培养均为阴性。2)检测覆盖明胶和水的金属平板上的灰化效果。3)对牙髓表面进行3种不同的处理方法(等离子体处理、蒸汽热处理和高温处理)。扫描电子显微镜观察表明，100W等离子体处理10min得到的表面最干净。综上所述，氧等离子体处理被认为是一种有用的牙齿消毒器。较少

1. The Effect of Autoclaving on the Bearing of the Air-turbine HandpiecesOf the dental instruments there are special difficulties in the disinfection of dental air-turbine handpieces (THP). The difficulty exists in their complex, delicate mechanical structure, the cost of purchasing extra sets to fill the vacancy during disinfection cycles and shortening of their useful life by autoclaving procedure. The purpose of this study is to clarify the delicate mechanical structure of eight THPs, and to evaluate the change of characteristics of THPs after repeated autoclaving (121ﾟC,15min).The results were as follows.1) Each dearing was composed of a outer ring, a inner ring, seven or eight balls and a supporter for the bearing ball (retainer). There was large difference in shape and materials of the retainer between THPs.2) The microscopic views indicated existence of some substances or many small holes in the surface of bearing part in all THPs, and some abrasion, or adhesion of the discolore … More d lubricating oil in soeme THPs. There was large difference in the damage of the bearing parts between THPs (Freedman's test)3) The THP sound was collected relationship between the rotor speed and repetitive autoclaving procedure to clarify the effect of autoclaving on the mechanical characteristics of the THP.THP sound was collected by a microphone and recorded on the magnetic tape and its power spectrum was analyzed by Fast Fourier Transformation (FFT) program on a stored program computer. The spectra obtained after 100 cycles autoclaving were different in frequency and relative power strength of the maximum peak frequency (MPF) from those of initial condition in all the THPs. In some of the THPs, change of the MPF not depending on the rotor speed was observed, those changes indicated the existence of some deformation in the internal structure of the THPs, especially in the retainer.The rotor sound is an useful clue to evaluate its mechanical condition.2. The Effect of an Oxygen Plasma TreatmentCorrosion of carbon steel instruments and the decomposed bacterial substances remaining on the surface of the instruments have been the problem with autoclave. The purpose of this study was to investigate the effect of an oxygen plasma reactor (PR-31 YAMATO Sci. Co. Ltd).1) When the power of 300 W was applied to the specimen contaminated by whole saliva (circa 10^4 to 10^6 CFU), all of the 25 cultures were negative.2) The ashed effect on the metal plate covered with gelatin and water was examined. This specimen lost weight by plasma treatment.3) The surface of the dental burs treated by 3 different methods (plasma treatment, steam heat and ary heat). The SEM views indicated that the plasma treatment of 100W for 10 min produced the cleanest surface. In conclusion, the oxygen plasma treatment was considered useful as a dental sterilizer. Less