环氧乙烷对牙科手机灭菌效果及机械性能影响的实验研究

目的 探讨环氧乙烷对人工污染牙科手机灭菌效果和机械性能的影响.方法 采用实验室代表菌种污染牙科手机,经环氧乙烷气体灭菌后,无菌检查法检查牙科手机的灭菌效果,用酶联免疫吸附实验(ELISA)法检测HBsAg;牙科手机每经20次灭菌后进行机械性能检测.结果 环氧乙烷灭菌法对实验室污染的牙科手机可全部达到灭菌效果,乙型肝炎表面抗原(HBsAg)抗原性全部灭活;经200次灭菌后10支牙科手机中,2支转速下降至30万r/min以下,仍高于16万r/min的标准转速.结论 牙科手机用环氧乙烷灭菌效果可靠,并可满足机械的使用性能.     

戊二醛对牙科手机灭菌效果的实验室评价

目的:探讨碱性戊二醛(Cidex)对人工污染牙科手机的灭菌效果.方法:将人工污染牙科手机分别浸泡在0.5%、1%和2%的碱性戊二醛消毒液中,作用不同时间后放入中和剂中和10分钟取出,将浸泡处理后的牙科手机放入洗脱液中洗脱震荡40秒,对洗脱液进行检测.结果:0.5%、1%碱性戊二醛(Cidex)浸泡处理污染牙科手机4小时及2%碱性戊二醛(Cidex)浸泡处理污染牙科手机2小时,HBsAg灭活率均为100%;2%碱性戊二醛浸泡污染牙科手机10小时,对牙科手机上污染的枯草杆菌黑色变种芽孢菌的平均杀灭率为99.99%;2%碱性戊二醛浸泡污染牙科手机10小时,对灭菌处理后牙科手机进行无菌检查,其中有9支无菌检查合格、1支检菌仍为阳性.结论:2%Cidex浸泡处理污染牙科手机可完全破坏HBsAg抗原性,用2%Cidex浸泡处理临床污染牙科手机可作为杜绝口腔科器械HBsAg医源性传播的主要措施之一.     

3种方法用于三用枪消毒的效果比较

目的比较3种方法用于三用枪消毒的效果。方法采用现场采样检测方法,对用消毒剂表面擦拭消毒、2%碱性戊二醛浸泡消毒和高温高压蒸气灭菌法灭菌效果进行观察。结果使用消毒剂表面擦拭消毒法,三用枪细菌总数超标率为9.09%;使用戊二醛浸泡消毒和高温高压灭菌法消毒,三用枪全部无菌生长。结论消毒剂表面擦拭法的消毒效果较差;高温高压蒸汽灭法消毒临床应用最为方便,效果最好。     

五种灭菌器对牙科手机灭菌效果的研究

目的检测5种灭菌器对牙科手机的灭菌效果.方法用酶联免疫吸附(ELISA)法检测5种压力蒸汽灭菌器灭菌后的HBsAg人为污染的牙科手机,并对5种灭菌器灭菌后的临床污染的牙科手机进行无菌检测,同时用嗜热脂肪杆菌芽胞检测5种压力蒸汽灭菌器的灭菌效果.结果 5种灭菌器生物监测均合格,5种压力蒸汽灭菌器杀菌效果都可达100%,其中2种灭菌器灭菌的所有牙科手机HBsAg抗原性检测均为阴性,其他3种灭菌器灭菌的牙科手机各有1支HBsAg抗原性检测为阳性.结论压力蒸汽灭菌器效果可靠,乙肝病毒是否灭活,还需做其他检测.牙科手机应严格遵守灭菌保养流程,灭菌后应洁净存放.     

口腔材料与器械

国产碳纤维桩的固位力实验；MTT法评价国产碳纤维桩材料的细胞毒性；五种牙本质粘接剂体外细胞毒性研究；环氧乙烷对牙科手机灭菌效果及机械性能影响的实验研究；不同材料根管桩剪切粘结强度的比较；树脂透明牙模型用于根管治疗操作训练的效果评价；反向沉淀法制备牙科纳米氧化锆粉体；口腔修复常用合金稳态电位的测定；三种金属处理剂对金属与复合树脂间剪切粘接强度影响的研究。[编者按]     

B级脉动真空压力蒸汽台式灭菌器对牙科手机灭菌效果分析

目的探讨B级脉动真空压力蒸汽台式灭菌器对牙科手机的灭菌效果。方法分析牙科手机灭菌器的选择、灭菌处理流程及灭菌效果监测,并对监测结果及牙科手机有效的灭菌方法进行评价。结果四川大学华西口腔医院采用B级脉动真空压力蒸汽台式灭菌器对牙科手机进行灭菌处理,其化学监测、生物监测指标均符合要求,灭菌有效率100%;对灭菌后牙科手机进行需氧培养、厌氧培养、乙型肝炎标志物监测均为阴性。结论对牙科手机采用B级台式灭菌器脉动真空压力蒸汽灭菌是行之有效的方法。     

牙科高速手机消毒灭菌方法的研究进展

牙科高速手机是口腔临床治疗中最常用的设备，在临床操作中较容易被病原微生物污染。研究表明，乙肝表面抗原的污染率在综合医院各科中，口腔科居首位。牙科高速手机如不经严格消毒灭菌，极易引发交叉感染。探讨和研究切实可靠的高速手机消毒灭菌方法刻不容缓。     

5种灭菌器对牙科手机性能的影响

目的 了解5种灭菌器对牙科手机机械性能的影响情况。方法 用5种灭菌器分别对4把牙科手机进行灭菌200次，每完成10次灭菌全过程检测一遍牙科手机的夹持力和转速。结果 经200次灭菌后20支牙科手机中，1支停转，另有8支转速下降，低于30万转／分钟，但高于16万转／分钟．可满足基本使用要求。灭菌时间最短的灭菌器只明显影响一支牙科手机的转速，其他灭菌器均明显影响两支牙科手机的转速。结论 灭菌时间短对牙科手机机械性能影响小，灭菌前应做好牙科手机的清洁和润滑，以减少机械性能损耗。     

牙科高速手机细菌回吸量的体外实验研究

目的 :研究不同细菌浓度、不同转动次数以及不同外表面消毒剂对手机细菌回吸量的影响。方法 :随机抽取新的牙科高速手机 2 0支 ,分别比较不同细菌浓度、不同转动次数和用不同外表面消毒剂消毒后 ,手机细菌回吸量的多少。结果 :随细菌浓度增大 ,手机细菌回吸量增多 ,不同浓度组间两两比较均有显著性差异 (P <0 0 5 ) ;在不同转动次数下手机细菌回吸量无显著性差异 (P >0 0 5 ) ;常用的消毒剂对手机外表面均能达到理想的消毒效果 ,但仅用外表面消毒不能减少手机内部的细菌回吸量。结论 :细菌浓度是影响手机内部回吸量的关键。     

不同灭菌法对齿科高速裂钻力学性能的影响

目的研究齿科常用的3种灭菌方法（干热法、湿热法、化学浸泡法）对牙科高速裂钻力学性能的影响。方法将200根全新的钨钢高速裂钻随机分为10组。分别通过弯曲实验和扭转实验观察高速裂钻在不同灭菌方法处理后弯曲强度、弹性模量和扭转强度等力学指标的改变。结果干热灭菌法、化学浸泡法和湿热灭菌法对裂钻的力学性能均有影响,随着灭菌次数的增加,裂钻的弯曲强度、弹性模量和扭转强度均相应减弱。3种灭菌方法比较发现,湿热处理引起裂钻的力学性能降低最明显,而化学浸泡和干热处理引起的变化相似,且较小。结论不同灭菌方法对高速裂钻产生一定的作用,影响大小排列依次为：湿热法、化学浸泡法、干热法。鉴于干热灭菌腐蚀作用最弱,建议齿科常用的小型器械可使用干热灭菌法进行灭菌。     

两种清洗方式对污染牙科手机洗涤效果分析

目的比较2种清洗方式对污染牙科手机上标准微生物的清洗效果。方法分别用标准试验菌株枯草杆菌黑色变种芽孢和大肠杆菌的菌悬液污染牙科手机机头各23支;3支污染后直接放入洗脱液,取洗脱液作为清洗前对照;另外20支分别采取手工刷洗10支,超声波清洗10支,再分别放入洗脱液,收集清洗后的洗脱液,分别接种培养,计数存活的标准试验菌菌落数,计算清除率。结臬对人工污染枯草杆菌黑色变种芽孢和大肠杆菌的牙科手机,手工刷洗后2种细菌清除率分别为86．66％、88．82％;超声波清洗后2种细菌清除率分别为90．68％、93．56％,2种方法的清除率有非常显著性差异（P〈0．01）。结论对人工污染2种标准试验菌株的牙科手机,超声波清洗效果优于手工刷洗效果。     

The effectiveness of two sterilization methods when different precleaning techniques are employed

The effectiveness was investigated of methods for the preparation of dental handpieces prior to sterilization procedures utilizing ethylene oxide (ETO) gas. The handpieces were cleaned using either a forced-air purging unit (group 1) or by flushing with air and water from the dental unit (group 2). They were inoculated with either Bacillus subtilis or Streptococcus mutans. After exposure to either steam or ETO gas, the handpieces were flushed with saline and the viability of recovered bacteria assessed. No viable bacteria were recovered from group 1 handpieces treated with either ETO gas or steam. However, viable S. mutans were recovered from group 2 handpieces following exposure to ETO gas. Thus, the use of a high-pressure forced-air purging unit may be required for the reliable sterilization of dental handpieces by ETO gas, as viable S. mutans could be recovered from untreated handpieces exposed to ETO gas.     

Effects of the Nd:YAG dental laser on plasma-sprayed and hydroxyapatite-coated titanium dental implants: surface alteration and attempted sterilization.

The Nd:YAG dental laser has been recommended for a number of applications, including the decontamination or sterilization of surfaces of dental implants that are diseased or failing. The effects of laser irradiation in vitro (1) on the surface properties of plasma-sprayed titanium and plasma-sprayed hydroxyapatite-coated titanium dental implants, and (2) on the potential to sterilize those surfaces after contamination with spores of Bacillus subtilis have been examined. Surface effects were examined by scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction after laser irradiation at 0.3, 2.0, and 3.0 W using either contact or noncontact handpieces. Controls received no laser irradiation. Melting, loss of porosity, and other surface alterations were observed on both types of implants, even with the lowest power setting. For the sterilization study, both types of implants were first sterilized by exposure to ethylene oxide and then contaminated with spores of B subtilis. After laser irradiation, the implants were transferred to sterile growth medium and incubated. Laser irradiation did not sterilize either type of implant. The spore-contaminated implants in the control group were successfully sterilized with ethylene oxide.     

Steam sterilization of air turbine dental handpieces

The efficacy of autoclaving high-speed dental handpieces was tested in two types of downward displacement steam sterilizers (instrument autoclaves), commonly used in the dentist's office. Eight series of experiments were performed with various sterilization schedules. Lubrication oils with or without antimicrobial agent were used in four of the series. Each handpiece was inoculated with 1 ml of a suspension containing equal amounts of saliva and spores of Bacillus stearothermophilus (approx. 10(6) spores/ml). Neither sterilization at 120-124 degrees C for 20 min nor at 134-136 degrees C for 10 min resulted in complete inactivation of the spores in series in which the instruments were tested without oil or with oil containing no antimicrobial agent. However, when the handpieces were lubricated with oil containing isopropanol and formaldehyde and the schedule 134-136 degrees C/10 min was used, no growth was observed. The results indicate that instrument autoclaves with built-in programs of 120-124 degrees C/20 min and 134-136 degrees C/10 min could have insufficient capacity to sterilize lubricated or unlubricated dental handpieces. The use of oils containing an antimicrobial agent can overcome this problem.     

2％酸性戊二醛对藻酸盐印模浸泡消毒的效果评价

目的评价2％酸性戊二醛浸泡消毒对藻酸盐印模表面的变形链球菌“C”、白色念珠菌、大肠杆菌、金黄色葡萄球菌和枯草杆菌黑色变种芽孢的消毒效果。方法制作5cm×5cm大小无菌印模试件,分成5组,分别用变形链球菌“C”、白色念珠菌、大肠杆菌、金黄色葡萄球菌和枯草杆菌黑色变种芽孢5种菌液污染。采用2％酸性戊二醛对染菌印模进行浸泡消毒处理,以蒸馏水浸泡作为对照组。其后不同时间在印模试件表面取样、接种、培养,并进行CFU计数,计算抑菌率。根据抑菌率大小评价消毒效果。结果2％酸性戊二醛浸泡消毒10min,可对藻酸盐印模表面的变形链球菌“C”、白色念珠菌、大肠杆菌和金黄色葡萄球菌达到有效消毒,在实验限定的作用时间内对枯草杆菌黑色变种芽孢消毒无效。结论2％酸性戊二醛浸泡为有效的印模消毒方法,但不能达到高水平的消毒。     

Autoclaving of lubricated dental instruments.

Test organisms forced mechanically into lubricated, rotating dental instruments (handpieces) were all killed during autoclaving at 134 degrees C for 8 min, even when protected by serum and oil. The test organisms were: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and spores of Bacillus stearothermophilus. Also when testing the sterility of autoclaved simulated instrument surfaces (brass cylinders and pieces of a cotton fabric) which had been inoculated with bacteria and dried before they were sprayed with oil, there was no growth of the test organisms. In addition to the other test organisms, spores of Bacillus subtilis and Gram-positive, anaerobic bacteria isolated from used handpieces that had been exposed to several autoclavings were used. Some of the handpieces that had been left to dry after use in the dentist's office before they were autoclaved, were shown not to be sterile. Therefore, the authors suggest that autoclaving of the instruments should take place shortly after use and prescribed cleaning.     

Sterilization beneath rings on dental instruments.

This study determined the effectiveness of standard methods of instrument sterilization beneath instrument rings. Sets of three types of dental instruments were contaminated with known amounts of bacterial spores (Bacillus stearothermophilus or Bacillus subtilis). Instrument rings were placed over the contamination and the instruments processed through standard cycles in a steam autoclave, an unsaturated chemical vapor sterilizer, a standard dry heat sterilizer, an ethylene oxide gas sterilizer or a 2.0% alkaline glutaraldehyde solution. Controls consisted of spore-contaminated instruments without rings that were not processed through any sterilizing method and that were processed through each sterilizing method. All instruments and their associated rings were cultured for the presence of live spores. The results indicate that the reliability of sterilization beneath the instrument rings used is greatest if the ringed instruments are processed through a steam autoclave or an unsaturated chemical vapor sterilizer.     

Autoclave sterilization of dental handpieces: A literature review

PurposeThe present review aimed to investigate autoclave sterilization of dental handpieces based on available studies.Study selectionThe sterilizing efficiency of dental handpieces with autoclave is mainly affected by the types of apparatus (N, B, and S), the packaging with sterilizing pouch, cleaning, and lubrication. These subjects were reviewed based on the in vitro experimental studies.ResultsDental handpieces can be sterilized, including inactivation of heat-resistant bacterial spores, with type B or type S sterilizers, regardless of the use of a sterilization pouch. In contrast, although type N autoclaves are capable of sterilization of general bacteria such as Streptococcus salivarius even in a sterilization pouch if instruments are washed beforehand, complete sterilization of the wrapped handpiece is not always achieved. Therefore, to achieve sterilization efficiency with type N autoclaves, processing without any packaging is recommended. As regards cleaning of handpiece, although contamination decreases with irrigation and wiping of handpieces, all reports concluded that these treatments alone do not achieve complete decontamination of reusable handpieces.ConclusionAlthough type B and type S autoclaves allow us to sterilize the dental handpieces, it is important to realize that complete sterilization of the handpiece is not always achieved by type N autoclave. Understanding autoclave processing of handpieces is essential for dental practice to deliver the safe dental care.