A critical appraisal of studies on cyclic fatigue resistance of engine‐driven endodontic instruments

The endodontic literature contains a plethora of studies on static and dynamic cyclic fatigue resistance tests performed on a large array of rotary or reciprocating nickel–titanium endodontic instruments. It was the aim of this review to summarize the currently available evidence to point out the different outcomes from static versus dynamic tests and to assess whether cyclic fatigue tests provide useful data and information for clinical practice. An electronic literature research in the database PubMed was performed using appropriate search terms, and the titles and abstract were screened for relevance. Language was restricted to English. The review reveals marked differences between the results obtained in static and dynamic tests, and also, the results for the same instruments assessed either under static or dynamic experimental conditions are widely inconsistent. Between the lowest and the highest value for one and the same pathfinding instrument was a factor of about 123 when cyclic fatigue was assessed either under static or dynamic experimental conditions. Moreover, standard deviations of up to 30% have been reported. Environmental temperature has a 500% impact on the lifetime of instruments. In conclusion, fatigue resistance tests conducted under room temperature should be regarded as having little meaning and the scientific and clinical benefits of fatigue resistance tests are very limited. These data should be provided by the manufacturer of the instruments.     

Evaluation of the Essen Rotary as a new technique for bacterial swabs: results of a prospective controlled clinical investigation in 50 patients with chronic leg ulcers

Most chronic wounds are colonised with different microorganisms, especially problematic bacteria like methicillin‐resistant Staphylococcus aureus (MRSA), which represent an increasing therapeutic challenge in the modern wound therapy regimen. Therefore, it is essential to specify the bacteria in wounds for an individual‐specific treatment. In most patients, an exemplary bacterial swab is taken from the centre of the wound surface. This so‐called Levine technique is propagated currently as the gold standard. The aim of our clinical investigation was to compare the results of different swab techniques to the new established Essen Rotary. In this monocentric prospective investigation, 50 patients with chronic leg ulcers were examined consecutively. The results of our clinical study show that bacteria are heterogeneously spread on wound surfaces. The analysis of the semiquantitative measured results showed that the Essen Rotary could detect significant more bacteria with a total amount of 111 bacteria (P = 0·049) compared to usual swab techniques. Considerably, only the Essen Rotary identified five compared to three MRSA‐patients detected by other techniques. The Essen Rotary is an efficient, economic and uncomplicated modification of bacteriological swab techniques which detects significant more bacteria compared to other conventional swab techniques. Therefore, the Essen Rotary may become the new gold standard in routinely taken bacteriological swabs especially for MRSA screenings in patients with chronic leg ulcers.     

Leveraging non-binding instruments for global health governance: reflections from the Global AIDS Reporting Mechanism for WHO reform

As countries contend with an increasingly complex global environment with direct implications for population health, the international community is seeking novel mechanisms to incentivize coordinated national and international action towards shared health goals. Binding legal instruments have garnered increasing attention since the World Health Organization adopted its first convention in 2003.     

COVID-19疫情中的生物力学问题

新型冠状病毒肺炎自爆发以来,已成为全球关注的焦点。由于疫情来势迅猛,给医疗制度体系、医疗资源、应急处置、医疗器械等提出了严峻的挑战,也暴露出其中诸多不足。以病毒的体外活性规律研究、气溶胶传播的生物力学问题、呼吸性疾病对心血管疾病影响的研究、公共交通和公共场所中通风方式的改进、医疗器械的生物力学研究为例,应用生物力学的原理、观点和方法,认识和剖析其中所存在和亟待改进的问题,期望生物力学能在疫情防控中发挥学科优势和力量,以此促进生物力学学科发展。     

基于双目视觉的医疗器械3D数据模型获取方法研究

目的：为了高效率、低创伤地完成外科手术．计算机辅助外科手术得到了广泛应用。医疗器械3D数据模型可有效地结合病人的影像数据,指导外科医生完成顺利外科手术,从而降低手术的风险,减少对病人的伤害。方法：基于双目视觉基本原理,首先对双目摄像机进行立体标定,利用标定后获得的摄像机参数对双目立体图像进行畸变矫正和立体校正,然后为了提高后续匹配精度,对医疗器械目标进行分割后再进行立体匹配,最后将获取的匹配视差信息重投影到3D空间。获得医疗机械的3D数据。结果：采用交互式分割方法对医疗器械目标进行先分割再立体匹配,能避免遮挡造成的误匹配。大大提高匹配精度。通过实验,将基于双目视觉获取的医疗器械3D数据与实际测量获得的数据进行比较后发现,本文方法获取的医疗器械3D数据精确度较高。结论：基于双目视觉理论可以高效率、高精度地进行医疗器械3D模型还原．其模型可用于模拟手术、手术导航等实际应用。     

Cutting Efficiency of Reciproc and WaveOne Reciprocating Instruments

Introduction

The aim of the present study was to evaluate the cutting efficiency of 2 new reciprocating instruments, Reciproc and WaveOne.

Methods

Twenty-four new Reciproc R25 and 24 new WaveOne Primary files were activated by using a torque-controlled motor (Silver Reciproc) and divided into 4 groups (n = 12): group 1, Reciproc activated by Reciproc ALL program; group 2, Reciproc activated by WaveOne ALL program; group 3, WaveOne activated by Reciproc ALL program; and group 4, WaveOne activated by WaveOne ALL program. The device used for the cutting test consisted of a main frame to which a mobile plastic support for the handpiece is connected and a stainless steel block containing a Plexiglas block (inPlexiglass, Rome, Italy) against which the cutting efficiency of the instruments was tested. The length of the block cut in 1 minute was measured in a computerized program with a precision of 0.1 mm. Means and standard deviations of each group were calculated, and data were statistically analyzed with 1-way analysis of variance and Bonferroni test (P < .05).

Results

Reciproc R25 displayed greater cutting efficiency than WaveOne Primary for both the movements used (P < .05); in particular, Reciproc instruments used with their proper reciprocating motion presented a statistically significant higher cutting efficiency than WaveOne instruments used with their proper reciprocating motion (P < .05). There was no statistically significant difference between the 2 movements for both instruments (P > .05).

Conclusions

Reciproc instruments demonstrated statistically higher cutting efficiency than WaveOne instruments.     

Cyclic Fatigue Resistance of Nickel-Titanium Instruments after Immersion in Irrigant Solutions with or without Surfactants

Introduction

The aim of the study was to assess cyclic fatigue resistance of reciprocating (Reciproc and WaveOne) and continuous rotating (ProTaper) nickel-titanium files after immersion in different irrigation solutions with or without surfactants during several short time periods.

Methods

A total of 270 new Reciproc R25, WaveOne Primary, and ProTaper F2 files were tested. Instruments of each brand were divided into 1 control group (n = 10) formed by new files and 4 test groups (n = 20) formed by instruments dynamically immersed at 37°C for 16 mm in 5.25% sodium hypochlorite (NaOCl), Hypoclean (5.25% NaOCl with surfactant), 17% EDTA, or EDTA Plus (17% EDTA with surfactant). Each test group was subdivided into 2 subgroups (n = 10) on the basis of the time of dynamic immersion in the endodontic irrigant solution (45 seconds or 3 minutes). Resistance to cyclic fatigue was determined by recording time to fracture in a stainless steel artificial canal with a 60° angle of curvature and 5-mm radius of curvature. The fracture surface was examined by using scanning electron microscopy.

Results

Immersion in NaOCl did not reduce the cyclic fatigue of reciprocating or continuous nickel-titanium files. The 17% EDTA reduced the fatigue resistance of all instruments after 3 minutes. The immersion in irrigants with surfactants did not influence the cyclic fatigue of instruments except for Reciproc immersed in Hypoclean solution.

Conclusions

EDTA immersion reduced the cyclic fatigue resistance of all instruments after 3 minutes. Addition of surfactants did not influence the cyclic fatigue of files except when added to NaOCl when it contacts Reciproc instruments.     

口腔科常用医疗器械清洗消毒效果的评价

目的评价口腔科医疗器械常规清洗消毒的效果。方法选择2013年7月～12月口腔科使用过的非一次性医疗器械（拔牙钳、车针）共36669件,消毒供应室清洗消毒处理前后,对物体表面口腔常见的变形链球菌、白色念珠菌、金黄色葡萄球菌以及乙肝病毒进行检测,并用目测法分析清洗的质量,测评临床的满意度。结果（1）器械清洗消毒质量的合格数为35395件,合格率达到96．52％;（2）细菌和病毒检测结果显示,除了工作室桌子有10次细菌不达标以外,其余均未检出细菌和病毒;（3）紫外照射与高压的消毒效果差距较大,未高压的灭菌消毒效果低于高压的灭菌消毒效果;（4）临床使用满意度达到95．83％。结论经规范化清洗消毒与管理,基本能确保口腔器械的卫生安全,所采用的清洗消毒措施,在一定程度上能有效控制医院感染的发生。     

结合锥形束CT评价两种镍钛器械预备老年人磨牙弯曲根管的效果

目的：比较镍钛器械Twisted Files（TF）和ProTaper在老年人磨牙弯曲根管预备中的临床应用效果。方法：选择2011年8月至2013年8月在我科门诊就诊的有弯曲根管的牙髓炎或根尖周炎的老年患者磨牙90颗,随机分成三组,每组30颗,T组和P组分别采用机用镍钛器械Twisted Files（TF）和ProTaper以冠向下技术预备根管,K组采用手用不锈钢K锉以逐步后退法预备根管,全部患牙均采用冷牙胶侧方加压技术充填。记录三组病例根管预备时间和器械折断数,根据治疗前、中、后的X线片评价根管预备和充填情况,通过锥形束C T记录预备前后距离根尖3mm处根管偏移值。结果：T组、P组均能保持原根管的弯曲和走向,根管预备的锥度和流畅度好,根管充填质量高,T组的偏移量比P组和K组的偏移量小,三组间差异有统计学意义（P〈0.05）。T组的操作时间比P组和K组短,三组间差异有统计学意义（P〈0.05）。预备过程中T组未发生器械折断,P组3例发生器械折断。结论：TF相对与Protaper用于预备老年人磨牙弯曲根管,效率较高,成形效果佳,较安全,更适合于狭窄弯曲的老年根管。     

R-Endo镍钛系统在根管再治疗中的应用

目的评价R-Endo镍钛机用器械在离体牙根管再治疗中的应用性能。方法收集根尖孔发育完成的单根管恒牙,根据根管弯曲度分层随机分组。使用牙胶或RealSeal树脂充填,而后分别使用Gates-Glidden钻＋K锉、HERO 642镍钛机动和R-Endo镍钛机动再治疗。记录再治疗时间及从根尖孔推出的碎屑重量,并拍摄术后X线片,AutoCAD 2008软件分析残余充填材料与根管壁的面积比。结果 R-Endo镍钛系统再治疗时间较长（P＝0.003）;推出根尖孔碎屑量较Gates-Glidden钻＋K锉少（P＝0.001）,与HERO 642镍钛系统相比差异无统计学意义（P＝0.239）;根管内残余充填材料与根管壁的面积比低于其他两组,但差异无统计学意义（P＝0.157）。 RealSeal充填组再治疗时间（P＝0.001）和推出根尖孔碎屑（P＝0.028）均低于牙胶充填组,两者间差异均具有统计学意义（P＜0.05）。结论 R-Endo机动镍钛系统是根管再治疗的有效方法,其根管清理性能优于手动器械,对根尖周组织激惹度较传统手动器械小,但器械的安全性有待提高。