Classification and cyclic fatigue evaluation of new kinematics for endodontic instruments

This study evaluated the effect of new motions of the motor TriAuto ZX2 on the cyclic fatigue of endodontic instruments. Vortex Blue 35.06 instruments were divided into four groups (n = 10) and tested for fatigue in a curved artificial canal (90° and 2 mm radius) using the following motions: continuous rotation (CR), Optimum Torque Reverse (OTR) set at 180° and the Optimum Glide Path (OGP), which was tested at 90° and 240°. The time to fracture (TTF) and the lengths of the fractured fragments were recorded. The mean TTF was significantly different among the groups (anova , P < 0.05): OGP 90° (213.39 ± 27.45), OTR 180° (121.24 ± 17.03), OGP 240° (45.24 ± 5.61) and CR (8.43 ± 1.27). Weibull analysis confirmed the shortest life expectancy for CR and the longest survival for OGP at 90°. The resistance to fatigue was affected by motions and pre‐set angles. The proprietary movements that are currently available for endodontic instruments were classified according to their kinematics.     

Shaping ability of the M4 handpiece and Safety Hedstrom Files in simulated root canals

The aim of this study was to assess the shaping ability of the M4 reciprocating handpiece and Safety Hedstrom files in simulated canals. A total of 40 simulated canals of various angles and positions of curvature were prepared with an M4 handpiece using Safety Hedstrom files oriented with the ground, flattened surface towards the inner aspect of the curve. A standard regimen was adopted throughout. Pre- and post-operative longitudinal images of the canals were taken with a video camera and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount and location of resin material removed as a result of preparation were determined from composite images of superimposed pre- and post-operative views. Preparation time varied significantly (P<0.001) between the canal types; overall, 20° canals were prepared more quickly than 40° canals. Zips and elbows were observed in 16 out of the 40 canals with most (11) being created in 40° specimens. Ledges were found in 19 canals and perforations in only 1. There were no significant differences between canal shapes for these aberrations. Excessive removal of material from the inner aspect of the canal at the curve to create a danger zone was found in 20 canals, but only in those with 40° curves. Significant differences in total canal width between the canal types were seen at the zips (P<0.05), elbows (P<0.05) and danger zones (P<0.001). Transportation at the danger zones varied significantly (P<0.001) between canal types. Under the conditions of this study, the M4 handpiece and Safety Hedstrom files created hour-glass preparations in a substantial proportion of canals. In reality, the Safety Hedstrom file with its one flattened surface was ineffective at reducing removal of material along the inner aspect of canal curves in severely curved specimens and clearly has the potential to create strip perforations in teeth.     

医学影像存储的色彩模式和文件格式的比较

本文介绍了不同的影像色彩模式和影像文件常见存储格式的特点及其在应用上的优缺点，分析了影像色彩模式、文件存储的格式与影像质量、用途的关系。     

两种后牙根管预备方法的临床效果比较

目的 :评估 2种后牙根管预备方法的临床效果。方法 :采用机用镍钛扩大锉 (ProFile)和手用不锈钢扩大锉 (K file)扩大后牙根管 ,并对 2组病例术后疼痛以及充填情况加以比较。结果 :发现机用镍钛扩大锉扩大后牙根管 ,具有去除根管感染物质彻底 ,根管形态保持良好 ,速度快 ,术后疼痛率较低的优点 ,但易出现断针。而手用不锈钢扩大锉扩大后牙根管速度较慢 ,术后疼痛率略高 ,但不易出现断针 ,操作上容易掌握。结论 :2种后牙根管方法都有优缺点 ,可结合起来使用。     

Transition from Film to Electronic Media in the First-Year Medical School Gross Anatomy Lab

For the benefit of the first-year gross anatomy students, we digitized and published on a Web site images that had been collected over a 30-year period. We provided a CD-ROM (compact disk, read-only media) containing the image set in higher quality format to students and faculty. We supplemented basic images with hot topics such as CT angiography, virtual colonography, computer-aided diagnosis, and 3D post-processing. Full motion video and moving JPEG (Joint Photo Expert Group) animations were integrated into the atlas. On the post course questionnaire medical students reported that the images on CD-ROM were helpful during the course and for review prior to examinations. Faculty and medical students used the CD-ROM for problem-based learning sections and facilitator training. The images were clear and easily projected during review sessions and were useful for the small group sessions, where they served as examples of normal anatomy.     

利用Toad解决Oralce数据库表空间错误问题

数据库是整个信息系统的核心，传统方式的数据库管理一般采用Sqlplus等命令行工具书写SQL命令。相比之下，使用数据库管理工具Toad连接数据库，通过图形化界面解决数据库问题，减少操作失误和繁琐程度，有效降低数据库管理成本。     

Development of Innovative Contra-angle Handpiece Device with Piston Movement for Root Canal Preparation

IntroductionThe purpose of this study was to assess the optimal amplitude and weight of the newly developed contra-angle handpiece. The handpiece uses piston movement without using an endodontic motor and enables a safe, quick, and reliable canal preparation.MethodsA prototype handpiece was designed. Instrumentation was performed on root canal resin blocks by 20 operators in 3 groups: the prototype handpiece with an H file (a stainless steel #25 manual H file, the piston group), a manually standardized technique with a K file (stainless steel #15–25 K files, the manual group), and a nickel-titanium (NiTi) reciprocating file with an endodontic motor (Reciproc Blue R25 [VDW, Munich, Germany], the NiTi group). Transportation of the canal center line and the time required for preparation were measured and statistically analyzed.ResultsThe optimal condition was an amplitude of 1.35 mm and a weight of 61.0 g. Transportation of the canal center was observed in all groups. A statistically significant difference was found at 2.0–3.0 mm from the apical foramen between the piston or NiTi group and the manual group, but no significant difference was found between the piston and NiTi groups. The least transportation was found in the NiTi and piston groups. The handpiece with a #25 H file demonstrated a good centering ability, similar to the NiTi file, which enabled speedy preparation. The time required for preparation between the piston or NiTi group and the manual group was statistically different. No significant difference was observed between the piston and NiTi groups (P < .05).ConclusionsWe concluded that the newly designed handpiece achieved efficient canal preparation and negotiation. The handpiece could avoid endodontic accidents, including ledge formation, instrument separation, and perforation.     

Développement d’un réseau nosographique collaboratif

ObjectivesThe use of massive amounts of digital data in mental health offers interesting perspectives that could influence the evolution of psychiatric nosography. The characteristics of this data could become key elements to understand the future organization of knowledge — and debates — in psychiatry. Such an evolution could take different shapes, including the development of a collaborative and networked psychiatric classification.Materials and methodsSeveral issues related to the use of large amounts of data in psychiatry were identified and developed in this context: (1) the growth of new health related data producers and storers, which could influence the development of some research topics or diagnostics to the detriment of others, depending on the availability or profitability of this data; (2) the fact that mental health data is often available in an unstructured form: textual data, like reports of complementary examinations, reports of hospitalization or expertises, but also imageries or videos, from institutional or alternative sources; (3) the need of scalability and flexibility of this data, to make it possible to integrate recent discoveries as well as to take into account the phenomenon of pathomorphosis or cultural factors in psychiatry. A collaborative framework is proposed to answer each of these issues, including the possibility of integration of different data forms, associated with a complete traceability of sources and a nominal registration. The need to structure data is also specified, with the use of tags to modelize diagnostic consensus that include professionals, patients and families. This collaborative tool would make it possible to consider data resulting from perceptions of patients or their families, enabling patients to benefit from a higher level of confidence and engagement, and limiting the deleterious effects of stigmatization.ResultsThe possibilities of a collaborative web tool integrated into the French Shared Medical File (Dossier Medical Partagé) are described, and two examples of practical situations are presented: A mental health professional reporting his influences on the diagnosis of schizophrenia: he integrates the symptoms described by the German psychiatrist Karl Leonhard (Leonhard classification), cultural references (cinematographic reference like A beautiful mind directed by Ron Howard), and links to articles on medical and psychiatric comorbidities among adults with schizophrenia. In the other example, a psychiatrist uses this tool to develop a collaborative diagnosis that integrated an active participation of the patient around the diagnostic. In France, the latest version of the digital Shared Medical File was launched in November 2018. The integration of a collaborative nosographic tool into this file would be an interesting answer to the difficulties that might happen for its use with patients suffering from mental disorders. It could thus limit the stigmatization of a shared diagnosis and enable a better understanding of practices among mental health professionals.ConclusionThe psychiatrists use specific knowledge resulting from multiple influences and theoretical orientations. The risk of incomprehension of practices in psychiatry by patients and their families being major, nosographic research trying to include the coexistence of these orientations appears necessary. Moreover, in the context of the development of large-scale data processing, it is essential that a collaborative human-scale interpretation of this knowledge exists. This would make the psychiatric nosography an ethical tool, allowing an active participation and dialogue between patients, families and health professionals, that could become key features of future psychiatric nosography.     

Master apical file size – smaller or larger: a systematic review of healing outcomes

The purpose of this systematic review was to determine in patients undergoing root canal treatment, whether apical enlargement affected the healing outcome. A PICO (population, intervention, comparison and outcome) strategy was developed to identify studies dealing with apical size of canal and healing outcome as measured clinically and radiographically. The MEDLINE, Embase, Cochrane and PubMed databases were searched. Additionally, the bibliography of all relevant articles and textbooks was manually searched. Based on inclusion and exclusion criteria, two reviewers independently selected the relevant articles. Four articles were identified that met the inclusion criteria. There were no studies that evaluated apical enlargement and healing outcome using cone beam computed tomography. The results of the systematic review confirmed that more evidence‐based research in this area is needed. With the limited information available, the best current available clinical evidence suggests that for patients with necrotic pulps and periapical lesions, enlargement of the apical size would result in an increased healing outcome in terms of clinical and radiographic evaluations.