三种灭菌法对高速裂钻腐蚀和切削率的影响

目的:观察湿热灭菌法、干热灭菌法、化学浸泡灭菌法处理高速裂钻后其表面腐蚀情况,以及对高速裂钻切削率的影响。方法:100根新高速裂钻随机分成10组分别用3种灭菌方法处理5、10、15次,体视显微镜观察处理前后裂钻表面形态的变化,参考Siegel标准自制设备测试裂钻的垂直和侧向切削率,统计分析灭菌处理对切削率的影响。结果:3种灭菌方法中,湿热灭菌法引起的裂钻表面腐蚀最严重;干热法最轻;湿热灭菌法引起的裂钻切削率下降幅度最明显,化学浸泡法、干热法次之。灭菌次数与腐蚀程度、切削率的降低幅度成正比,处理15次后,裂钻的垂直和侧向切削率均有明显下降。结论:湿热灭菌法引起的裂钻腐蚀改变最明显、切削率降低幅度最大,化学浸泡法、干热法较轻,建议牙用高速裂钻类小器械采用玻璃珠灭菌器进行灭菌。     

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。     

金刚砂车针清洗消毒及灭菌方法的研究现状

金刚砂车针因其结构复杂、直接与患者口腔接触及需要重复使用的特点,因此关于该车针的清洗消毒灭菌方法一直受到人们的关注。常用的金刚砂车针清洗、消毒、灭菌的方法主要有人工清洗法、酶清洗法、超声震荡法、化学液浸泡法、干热灭菌法和湿热灭菌法。上述方法均存在优点和不足,本文综述了上述方法的适用范围和优缺点以及最新的研究进展。     

2种方法在下颌水平阻生第三磨牙拔除中的比较

目的比较舌侧骨板劈开法与高速手机裂钻去骨法拔除下颌低位水平阻生第三磨牙的效果。方法将150颗下颌低位水平阻生第三磨牙随机分成2组, 每组75颗,分别采用舌侧骨板劈开法和高速手机裂钻去骨法拔除,记录手术时间及并发症情况并进行统计学分析。结果舌侧骨板劈开法和高速手机裂钻去骨法拔除下颌阻生第三磨牙的手术时间分别为（35.85±6.05）min和（43.52±7.70）min（P<0.05）。2种手术方法在骨折片去除、面部肿胀方面有统计学差异（P<0.05）,在牙龈撕裂、术后疼痛、张口受限、术后出血方面无统计学差异（P>0.05）。2种手术方法术后均未出现舌神经损伤及下唇麻木,高速手机裂钻去骨法发生干槽症1例。结论采用舌侧骨板劈开法拔除下颌低位水平阻生第三磨牙的手术时间短,且术中、术后并发症较少。     

高压蒸汽灭菌对3种机用镍钛器械形貌及抗力的影响

目的 比较高压蒸汽灭菌对3种机用镍钛器械（K3、Mtwo、ProTaper）形貌及循环疲劳抗力的影响。方法 分别选取3种不同品牌的机用镍钛器械K3、Mtwo、ProTaper各36根。首先取各品牌器械24根,分为4组（n=6）,分别进行循环高压蒸汽灭菌0、1、5、10次后,在人工根管内自由旋转至器械折断,记录折断前的旋转时间和折断尖端长度,采用SPSS13.0 软件包对数据进行单因素方差分析,比较其循环疲劳抗力的差别。再将剩余的器械各12根分为2组（n=6）,第1组不予处理,第2组循环高压蒸汽灭菌10次,扫描电镜观察各器械尖端外表面形貌及横截面形貌的改变。结果 未灭菌组中,循环疲劳抗力K3大于Mtwo,并大于ProTaper(P<0.05);K3组5、10次组较未灭菌组均表现出抗力增强趋势,仅10次组与未灭菌组间差异有显著性(P<0.05);ProTaper组所有灭菌组较未灭菌组均显著增强(P<0.05),其中,5次组抗力最大;Mtwo组中,随着灭菌次数的增加,循环疲劳抗力逐渐增强(P<0.05)。扫描电镜观察发现,镍钛器械外表面和内部的不规则缺陷在多次灭菌后均显著增加。结论 不同品牌器械之间循环疲劳抗力不同,高压蒸汽灭菌在一定程度上可增加镍钛器械的循环疲劳抗力,但却使器械表面的粗糙度增加,横截面微观缺陷增多。     

局部用奥威尔凝胶对酸性饮料导致年轻恒牙脱矿和再矿化的影响

目的比较局部使用奥威尔凝胶或氟保护漆对年轻恒牙抵抗饮料酸蚀及酸蚀后脱矿釉质再矿化的影响。方法观测年轻恒牙的釉质经饮料浸泡后再经奥威尔凝胶或氟保护漆局部处理,或奥威尔凝胶及氟保护漆处理后再经饮料浸泡的表面显微硬度（SMH）变化;应用扫描电子显微镜（SEM）观察各组釉质的表面形态。结果饮料浸泡后再经奥威尔凝胶或氟保护漆局部处理的年轻恒牙,其釉质的SMH明显增加（P<0.05）,奥威尔凝胶组的SMH高于氟保护漆组（P<0.05）。奥威尔凝胶或氟保护漆处理釉质表面后再经饮料浸泡,奥威尔凝胶组的SMH高于氟保护漆组（P<0.05）。SEM下可见各组釉质表面经饮料及奥威尔凝胶或氟保护漆处理后呈现不同程度的釉质溶解和再矿化。结论年轻恒牙釉质表面应用奥威尔凝胶可以增强釉质对饮料酸蚀的抵抗作用,促进脱矿釉质的再矿化。     

钛表面TiO2纳米孔对骨髓基质细胞黏附和铺展的影响

目的:体外研究钛表面TiO2纳米孔层结构对骨髓基质细胞(hone marrow stromal cells,BMSCs)的黏附、铺展形态等生物学特性的影响.方法:采用电化学阳极氧化法和化学腐蚀技术,在纯钛表面制备出特定尺度和形貌的TiO2纳米孔层结构,以猪BMSCs为研究对象,应用激光共聚焦显微镜、扫描电子显微镜等技术检测细胞黏附、铺展形态和骨架蛋白排列等生物学特性,采用SAS6.12软件包对数据进行t检验.结果:阳极氧化法和化学腐蚀技术制备的钛表面TiO2纳米孔层结构纳米尺度是孔径约为30nm,深度15nm.BMSCs接种于处理组材料与对照组材料4h和8h后,处理组钛片上细胞黏附数均显著大于对照组(P<0.05);在接种8h时,处理组材料表面细胞向多个方向伸出丰富细长伪足,细胞骨架蛋白粗大,铺展面积较大.对照组表面细胞伪足较少且粗短,细胞骨架蛋白细小,铺展面积较小;处理组细胞铺展面积是对照组的1.35倍(P=0.001).结论:阳极氧化法和化学腐蚀技术制备的钛表面TiO2纳米孔层结构对BMSCs的黏附、铺展等生物学行为起到显著的促进作用.     

表面离子交换处理对热压铸造陶瓷的硬度和断裂韧性影响的实验研究

目的研究陶瓷表面离子交换处理对热压铸瓷硬度和断裂韧性的影响。方法热压铸造圆形铸造陶瓷试件40个,分为4组,每组10个,放入人工唾液中浸泡1个月。抛光组试件仅打磨、抛光;上釉组试件打磨、抛光后放入烤瓷炉内上釉;离子交换组试件打磨、抛光后上釉,再置于硝酸钾离子交换剂中加热,室温冷却;对照组不作处理。测量计算试件的硬度值和断裂韧性值,并进行统计学分析。结果离子交换组与对照组的硬度值和断裂韧性值差异有统计学意义(P<0.01),抛光组和上釉组与对照组比较差异无统计学意义(P>0.05)。结论离子交换处理方法可以提高热压铸造陶瓷的硬度和断裂韧性。     

Er：YAG激光、含氟凝胶拮抗碳酸饮料对人乳牙釉质酸蚀作用的体外研究

目的：观察Er：YAG激光、1.23%酸性氟磷酸盐（acidulated phosphate fluoride,APF）凝胶应用于乳牙釉质表面后保护牙釉质抵抗碳酸饮料腐蚀的能力。方法：采用拔除的滞留乳磨牙,分为对照组、Er：YAG激光组、含氟凝胶组、激光和含氟凝胶联合处理组4组,每组15个,经碳酸饮料间断性浸泡后,比较各组激光荧光诊断仪（laser-induced fluorescence diagnostic,LF）读数的变化,并通过扫描电镜观察釉质表面形态的变化。结果：碳酸饮料浸泡可致乳牙釉质LF读数上升,经激光、含氟凝胶、激光与含氟凝胶联用的各处理组LF值均明显低于对照组（P〈0.05）,其中两者联用组最低,与其他两处理组相比差异有统计学意义（P〈0.05）;激光组与含氟凝胶组相比LF读数的变化无统计学差异（P〉0.05）。扫描电镜下可见釉质表面有不同程度的溶解。结论：碳酸饮料对乳牙釉质表面有较强的酸蚀脱矿作用,釉质表面应用氟化物或者Er：YAG激光可增强乳牙釉质抵抗碳酸饮料腐蚀的能力,两者联用效果更好。     

碘甘油引起口腔铸造用银铟合金表面腐蚀的初步研究

目的 通过分析合金的表面腐蚀产物,考察不同腐蚀反应时间碘甘油对口腔铸造用银铟合金的腐蚀情况。方法 制作口腔修复铸造用银铟合金测试件,对照组不与碘甘油接触,实验组浸入碘甘油发生腐蚀反应,反应时间分别为5 s、10 s、15 s、30 s、1 min、5 min、10 min、30 min,以扫描电子显微镜（SEM）观察试件表面形貌,再以X线能谱分析银铟合金表面腐蚀产物。结果 SEM结果显示:腐蚀是在整个金属表面上均匀进行的。对合金表面银、铟、锌、钯等离子质量百分比进行统计分析显示:对照组与10 s组及其以后所有实验组分别相比均有显著差异（P<0.05）,而10 s组及其以后各实验组之间两两相比并无显著差异（P>0.05）。结论 腐蚀特征为均匀腐蚀。腐蚀与腐蚀时间不呈线性增长关系,具体表现为腐蚀层银、铟、锌、钯离子含量在10 s显著减低,之后随时间的增加各离子含量基本稳定。     

Cutting effectiveness of diamond instruments subjected to cyclic sterilization methods

The effect of repeated sterilization on the cutting effectiveness of one brand of rotary dental diamond cutting instruments was measured. Four groups of five diamond burs were sterilized by four methods: (1) sterilization with a chemical agent (Sporicidin); (2) steam under pressure (autoclave); (3) dry heat (Dri-Clave); or (4) chemical vapor (Chemiclave). Each group of diamond instruments made a timed cut in a ceramic block. This cut and all subsequent cuts were measured and were used to determine a baseline cutting effectiveness. Each group of diamond burs was then ultrasonically cleaned, sterilized, and another cut was made. At the end of 10 cycles there was no difference in cutting efficiency of the dental diamond instruments. However, there are differences in the cutting efficiency of individual diamond instruments. The SEM evaluation made prior to cutting and at the end of the 10 cycles of sterilization demonstrated that diamond wear was similar in all groups and that little diamond particle loss occurred in any group.     

Effect of steam versus dry-heat sterilization on the wear of orthodontic ligature-cutting pliers.

The purpose of this study was to compare the wear of orthodontic ligature-cutting pliers after multiple cycles of cutting stainless steel ligature wire (.025 mm) and sterilizing with dry heat or steam autoclave. Fifty ligature-cutting pliers with stainless steel inserts were randomly divided into 2 equal groups to be sterilized in either dry heat or steam autoclave. Each plier was subjected to a series of ligature wire cuts followed by the assigned sterilization method. The amount of wear at the tip of each plier in both groups was measured with a stereo microscope system and digital photomicrography. Wear was defined as the difference in initial length from a marked reference line to the tip of the plier minus the length after 6 and 12 cycles of use and sterilization. There was no significant difference in the mean wear at the tip of the pliers between the 2 groups. It appears that there is no need to maintain both sterilization systems, dry heat and steam autoclave, in the orthodontic office. Steam autoclave sterilization can be used with no deleterious effects on the pliers if they are manufactured with stainless steel inserts.     

INFLUENCE OF MICROWAVE STERILIZATION ON THE CUTTING CAPACITY OF CARBIDE BURS

Objective:

This study compared the cutting capacity of carbide burs sterilized with microwaves and traditional sterilization methods.

Material and Methods:

Sixty burs were divided into 5 groups according to the sterilization methods: dry heat (G1), autoclave (G2), microwave irradiation (G3), glutaraldehyde (G4) or control – no sterilization (G5). The burs were used to cut glass plates in a cutting machine set for twelve 2.5-min periods and, after each period, they were sterilized (except G5) following the protocol established for each group. The cutting capacity of the burs was determined by a weight-loss method. Data were analyzed statistically by Kruskal-Wallis and Dunn''s test.

Results:

The means of the cutting amount performed by each group after the 12 periods were G1 = 0.2167 ± 0.0627 g; G2 = 0.2077 ± 0.0231 g; G3 = 0.1980 ± 0.0326 g; G4 = 0.1203 ± 0.0459 g; G5 = 0.2642 ± 0.0359 g. There were statistically significant differences among the groups (p<0.05); only dry heat sterilization was similar to the control.

Conclusion:

Sterilization by dry heat was the method that least affected the cutting capacity of the carbide burs and microwave sterilization was not better than traditional sterilization methods.     

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.     

Assessment of the effectiveness of dental sterilizers using biological monitors.

This study was undertaken to evaluate the effectiveness of steam, chemical vapor, and dry heat sterilizers, over a three-year period, in dental operatories subscribing to the University of British Columbia's sterilization monitoring service. A total of 4,579 sterilizer loads were tested. The results demonstrated an overall failure rate of 4.4 per cent. Individual failure rates for each type of sterilizer were: chemiclaves, 4.9 per cent; steam autoclaves, 2.3 per cent; and dry heat ovens, 7.9 per cent. In 38 per cent of these cases, the reasons for failure could be attributed to a definite cause.     

Instrumentation for placement of vitreous carbon endosseous implants.

The instruments required for placement, stabilization, and restoration of vitreous carbon endosseous implants are conventional in character and readily available. With the exception of extra-long burs for socket preparation, all instruments are normally available in dental offices. The surgery instruments should be rigorously sterilized prior to use, including the dental handpiece, burs, suction tip, etc. Gas sterilization techniques provide an effective means of sterilizing the surgical instruments without causing corrosion of burs and the handpiece.     

Effect of sterilization on the strength and cutting efficiency of twist drills

Retentive-pin twist drills were subjected to four methods of sterilization and then examined to determine possible effects on resistance to fracture, cutting efficiency, and surface condition. Sterilization methods included steam autoclave, chemical vapor autoclave, dry heat, and immersion in glutaraldehyde. Although the steam and chemical vapor groups had lower mean fracture strengths after sterilization, there was no statistically significant difference among the groups. Only the steam autoclave group showed a statistically significant loss of cutting efficiency. Scanning electron microscopic evaluation revealed that only drills sterilized by steam autoclave showed changes in the surface condition or cutting edges.