这项研究是由明尼苏达牙科研究中心生物材料与生物力学（MDRCBB）的支持。

注意：使用玻璃腔三牙复合树脂进行了研究：Z100，Z250和LS，如材料清单中列出。其中，LS是已知的以大约1.0％的体积收缩率的低收缩树脂复合材料，比Z250和Z100（〜2％和〜2.5％）18-19的要低得多。的设备和在本研究中使用的其它材料也被在物料列表给出。 1。模型腔准备<ol><li>切一个长圆筒形玻璃棒，直径10毫米，为使用低速金刚石锯片10毫米长的短杆。 </li><li>切近中-咬合-远端（MOD）的空腔（ 图1）测量3毫米（宽）×2毫米（深）在每个试样用适于低速金刚石锯。 </li><li>研磨下来每个圆柱形试样以创建一个平面上垂直于所述腔的长度，其尺寸如图1的平坦表面允许精确FOcusing并在复原图像校准。此后，它将被称为观测表面上 。 </li><li>准备3个标本的每个测试的三种材料：Z100，Z250和LS;见材料表。 </li></ol> 2，填充模腔与树脂复合<ol><li>用刷子silanize所有的玻璃腔体表面涂上一层薄薄的陶瓷底漆。这使得玻璃表面与树脂的复合材料之间的粘合。 </li><li>经过约1分钟，涂上一层薄薄的粘合剂。使用LS胶系统复合LS和Adper单键加复合Z100和Z250。 </li><li>固化粘合剂与固化灯和持续时间（10-20秒）根据制造商的说明书（材料表）。 </li><li>覆盖所有周围的恢复用黑胶带以外的观察面， 如图2中的玻璃表面，其目的是为了避免在固化光到达通过周围的透明玻璃，这不会发生在真牙树脂复合体。 </li><li>散装填充模腔与树脂复合材料和刮去多余的扁平化所有的表面。 </li></ol> 3，表面涂装<ol><li>喷一层薄薄的白色油漆到观察表面，其现在包括树脂复合体的一部分。 </li><li>立即撒上一些黑色细木炭粉上油漆来创建高对比度的斑点。该斑点的不规则形状将有助于DIC的软件来识别它们，然后跟踪他们的行踪。 </li></ol> 4，样品安装，固化，和拍摄<ol><li>参照图2，将一个样品（E）插入夹持器（C）中，用一个螺钉（D）拧紧。然后，将整个装置在一个大的水平梁的末端。 </li><li>安全CCD摄像机和一个黄色的照明LED灯到同一个光束，使得他们面临的观测中N曲面。 </li><li>使用一台具有可调节夹具，定位光固化，使得其前端在样品上方约1mm。 </li><li>取试样的图片来固化之前提供的参考图像。 </li><li>固化20秒的树脂复合材料。 </li><li>固化后拍摄另一张照片在5分钟。 </li><li>放置一个校正块在同一位置作为观察面和拍照。校准块包含圆点与尺寸和间距精确已知的阵列。 </li></ol> 5，与DIC的软件图像分析<ol><li>进口对各样品，一前一固化，进入DIC软件后两张图片。 </li><li>校准的图像的尺寸和纠正使用校准块的图像的图像失真。 。 </li><li>定义感兴趣的区域的观察面内进行分析。 </li><li>定义的平方子窗口的大小为64 x 64像素的第一次迭代和32×32像素的第二次迭代20。定义重叠为50％。 </li><li>关联与固化来计算位移和应变分布前拍摄的参考图像固化后拍摄的图像。 </li></ol>

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作者宣称，他们有没有竞争的财务权益。

与收缩应变的测量相同的形状和尺寸中使用玻璃腔是在结果中的变化最小化由于在大小，解剖学和天然人类牙齿材料性质的差异。另外，在本研究中使用的熔凝石英玻璃具有类似的杨氏模量对牙釉质，使其成为一个合适的模拟物材料为天然牙齿只要机械行为方面21-22。虽然在真实牙齿修复体，树脂复合材料主要是结合到牙质，而不是搪瓷，并且有两个牙体组织之间的硬度差，预计不会有较...

树脂基复合材料被广泛使用，因为其卓越的美学和操控性能在口腔修复。然而，尽管被粘结到牙齿组织中的树脂复合材料的聚合收缩仍然是临床关注，开发了收缩应力可能会引起脱粘在牙齿修复接口1 -2。因此，细菌可侵入和驻留在失败的领域，并导致继发龋。另一方面，如果恢复是公粘结到牙齿，收缩应力可能引起牙齿组织开裂。无论这些故障将危及使用寿命的牙修复体，其将受到大量的热负荷和机械负荷的循环。 聚合收缩应变和应力的测量牙科复合树脂3-4的开发和评估也因此成为不可或缺的</SUP&gt;。各种测量技术或方法已被开发5-11以提供一个简单的设置，用于测量的树脂复合材料的收缩行为可靠的主要目的。而它们所提供的测量值可能是足够的，用于比较不同材料的收缩行为，它们不会在收缩应力在实际恢复牙齿哪里如何开发有助于理解。具体地讲，的极大兴趣问题是空心墙如何约束复合材料和导线的收缩在牙齿修复12创造收缩应力。需要注意的是，要创建的收缩应力，树脂复合材料的收缩变形的部分具有被转换成拉伸弹性应变。因此，这将是有用的，如果在恢复的应变的该组件可以被测量。最近，光学全视野应变测量技术，数字图像相关（DIC），已经被应用到自由shrinka的测定在牙科修复13-15的树脂复合材料GE以及物料流。 DIC的基本思想是从它的变形过程中，据此，位移和应变场超过该表面可以被确定拍摄连续图像在样品表面跟踪和关联可见的图案。全视场测量的DIC的方法，该方法是在观察非均匀变形和应变图案13是特别有用的主要优点之一。在这项研究中，DIC是用来揭示的应变模式在牙科复合树脂修复，以了解收缩应力的发展及物色潜在位点剥离的目的。这个信息是不是在上面14-15列举的作品，其中仅测得的修复体的位移，由于聚合收缩直接可用。该测定是使用模拟的牙近中 - 牙合 - 远（MOD）齿腔作为企图复制品的模型进行忒现实牙齿修复的应力或应变。虽然使用真实牙齿更解剖学代表的该缺点是在解剖结构，机械性能，水化程度以及看不见的内部缺陷14的齿之间的显著本质上的差异所导致的大的变化的结果。为了克服这种缺陷，一些研究试图通过将它们分组在颊大小16方面或完全取代了牙齿替代材料17的模型，规范的牙齿样本。例如，铝塑其中有一个类似的杨氏模量，以珐琅（69和83 GPa时，分别）已受聘在收缩应力测量，收缩应力所指出的风口浪尖上偏转17的水平。在这项研究中，石英玻璃的模型（模腔）被用来代替，因为该材料也具有类似的杨氏模量（63 GPa）的对牙釉质和，因为它是透明耳鼻喉科，在标本的任何剥离或开裂可以很容易地观察到。

<table border="0" cellpadding="0" cellspacing="0" width="790">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:191px;">Dental composite Z100</td>
			<td style="width:167px;">3M ESPE</td>
			<td style="width:175px;">N362979</td>
			<td style="width:259px;">volume shrinkage ~ 2.5%, Young&#39;s modulus ~ 14 GPa</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:191px;">Dental composite Z250</td>
			<td>3M ESPE</td>
			<td style="width:175px;">N326080</td>
			<td style="width:259px;">volume shrinkage ~ 2.0%, Young&#39;s modulus ~ 11 GPa</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:191px;">Dental composite LS</td>
			<td>3M ESPE</td>
			<td style="width:175px;">N240313</td>
			<td style="width:259px;">volume shrinkage ~ 1%, Young&#39;s modulus ~ 10 GPa</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ceramic Primer</td>
			<td>3M ESPE</td>
			<td style="width:175px;">N167818</td>
			<td style="width:259px;">Rely X</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LS System Adhesive</td>
			<td>3M ESPE</td>
			<td style="width:175px;">N391675</td>
			<td style="width:259px;">Adhesive for compoiste LS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Adper Single Bond Plus</td>
			<td>3M ESPE</td>
			<td style="width:175px;">501757</td>
			<td style="width:259px;">Adhesive for compoiste Z100 and Z250</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass rod&#160;</td>
			<td>Corning Inc.</td>
			<td>&#160;Pyrex 7740 borosilicate&#160;</td>
			<td style="width:259px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:191px;">Curing light&#160;</td>
			<td>3M ESPE</td>
			<td>Elipar S10&#160;</td>
			<td style="width:259px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:191px;">White paint&#160;</td>
			<td>Krylon Product Group</td>
			<td style="width:175px;"></td>
			<td style="width:259px;">Indoor/Outdoor, Flat white</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:191px;">Charcoal powder&#160;</td>
			<td>Sigma Aldrich, Co.</td>
			<td style="width:175px;">BCBH6518V</td>
			<td style="width:259px;">Fluka activated charcoal</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CCD camera&#160;</td>
			<td>Point Grey Research, Inc.</td>
			<td>Point Grey Gras-20S4C-C</td>
			<td style="width:259px;"></td>
		</tr>
	</tbody>
</table>

shrinkage of dental composite in simulated cavity measured with digital image correlation

牙科复合树脂聚合收缩可导致恢复剥离或破裂的牙齿组织中合成，恢复牙齿。为了了解在何处和如何收缩应变和应力的经修复的牙齿发展，数字图像相关（DIC）是用来提供模型修复中的位移和应变分布是经历了聚合收缩的全面视图。 标本与模型腔进行了圆柱形玻璃棒与直径和长度为10毫米制成。近中牙合 - 远（MOD）在每个试样制备腔体的尺寸测量，在3毫米和2毫米的宽度和深度分别。用复合树脂充填型腔后，在观察的表面喷上首次一层薄薄的白色油漆，然后细黑木炭粉打造高对比度的斑点。固化后与之前5分钟，然后拍摄的照片的表面。网络连接应受，这两个图片是使用DIC的软件来计算位移和应变分布相关。 的树脂复合垂直缩水朝向空腔的底部，与具有最大向下位移的恢复的顶部中心部分。在同一时间，它收缩水平朝向其垂直中线。复合材料的收缩率拉伸的材料，在“牙齿修复”界面附近，导致周围的复原牙尖挠度和高的拉伸应变。材料靠近腔壁或地板大都在垂直于界面的方向有直接的菌株。两个直接应变分量的求和表明围绕恢复相对均匀的分布，其大小等于约到的材料的体积收缩应变。

三个试样进行了测试的每种材料。每次试验后，试样进行了检查眼睛或，如果需要，使用显微镜。在“牙齿修复”界面或裂缝没有明显的剥离被发现。 图片的分辨率为1,600×1,180像素，5.8毫米的像素大小。具有32个像素的子集的窗口的大小，位移分布的空间分辨率约为186毫米。 图3显示了固化的修复与Z250制成的位移矢量的典型曲线图。标本与?...

Watch this Scientific Journal Video about Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation at JoVE.com

Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation

为了了解聚合收缩应力的牙科树脂的复合树脂修复的空间发展，数字图像相关被用于通过关联聚合前后所采取的恢复的图像，以提供恢复的模型玻璃腔的全视野的位移/应变测量。

牙科复合材料在模拟腔收缩测量与数字图像相关

Polymerization shrinkage of dental resin composites can lead to restoration debonding or cracked tooth tissues in composite-restored teeth. In order to ...

shrinkage-dental-composite-simulated-cavity-measured-with-digital

Research

JoVE Journal

Medicine

13.4K 次观看.  University of Minnesota. 为了了解聚合收缩应力的牙科树脂的复合树脂修复的空间发展，数字图像相关被用于通过关联聚合前后所采取的恢复的图像，以提供恢复的模型玻璃腔的全视野的位移/应变测量。 

视频: Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation

Stem Cell Transplantation in an in vitro Simulated Ischemia/Reperfusion Model

Stem cell transplantation protocols are finding their way into clinical practice1,2,3. Getting better results, making the protocols more robust, and finding new sources for implantable cells are the focus of recent research4,5. Investigating the effectiveness of cell therapies is not an easy task and new tools are needed to investigate the mechanisms involved in the treatment process6. We designed an experimental protocol of ischemia/reperfusion in order to allow the observation of cellular connections and even subcellular mechanisms during ischemia/reperfusion injury and after stem cell transplantation and to evaluate the efficacy of cell therapy. H9c2 cardiomyoblast cells were placed onto cell culture plates7,8. Ischemia was simulated with 150 minutes in a glucose free medium with oxygen level below 0.5%. Then, normal media and oxygen levels were reintroduced to simulate reperfusion. After oxygen glucose deprivation, the damaged cells were treated with transplantation of labeled human bone marrow derived mesenchymal stem cells by adding them to the culture. Mesenchymal stem cells are preferred in clinical trials because they are easily accessible with minimal invasive surgery, easily expandable and autologous. After 24 hours of co-cultivation, cells were stained with calcein and ethidium-homodimer to differentiate between live and dead cells. This setup allowed us to investigate the intercellular connections using confocal fluorescent microscopy and to quantify the survival rate of postischemic cells by flow cytometry. Confocal microscopy showed the interactions of the two cell populations such as cell fusion and formation of intercellular nanotubes. Flow cytometry analysis revealed 3 clusters of damaged cells which can be plotted on a graph and analyzed statistically. These populations can be investigated separately and conclusions can be drawn on these data on the effectiveness of the simulated therapeutical approach.

Stem Cell Transplantation in an in vitro Simulated Ischemia/Reperfusion Model

We demonstrate how to set up an in vitro ischemia/reperfusion model and how to evaluate the effect of stem cell therapy on postischemic cardiac cells.

在干细胞移植在体外模拟缺血/再灌注模型

Stem cell transplantation protocols are finding their way into clinical practice1,2,3. Getting better results, making the protocols more robust, and ...

科研

医学

Orthotopic Hind Limb Transplantation in the Mouse

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and translational research in the field of transplantation medicine. A vast array of reagents is available exclusively in this setting, including mono- and polyclonal antibodies for both diagnostic and interventional applications. In addition, a vast number of genotyped, inbred, transgenic, and knock out strains allow detailed investigation of the individual contributions of humoral and cellular components to the complex interplay of an immune response and make the mouse the gold standard for immunological research. 
Vascularized Composite Allotransplantation (VCA) delineates a novel field of transplantation using allografts to replace "like with like" in patients suffering traumatic or congenital tissue loss. This surgical methodological protocol shows the use of a non-suture cuff technique for super-microvascular anastomosis in an orthotopic mouse hind limb transplantation model. The model specifically allows for comparison between established paradigms in solid organ transplantation with a novel form of transplants consisting of various different tissue components. Uniquely, this model allows for the transplantation of a viable vascularized bone marrow compartment and niche that have the potential to exert a beneficial effect on the balance of immune acceptance and rejection. This technique provides a tool to investigate alloantigen recognition and allograft rejection and acceptance, as well as enables the pursuit of functional nerve regeneration studies to further advance this novel field of transplantation.

This novel model for orthotopic hind limb transplantation in the mouse, applying a non-suture cuff technique for super-microvascular anastomosis, provides a powerful tool for in&#160;vivo mechanistic immunological research related to vascularized composite allotransplantation (VCA).

原位后肢移植中的鼠标

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and ...

Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping

Recent genome-wide association studies targeting atrial fibrillation (AF) have indicated a strong association between the genotype and electrophysiological phenotype in the atria. That encourages us to utilize a genetically-engineered mouse model to elucidate the mechanism of AF. However, it is difficult to evaluate the electrophysiological properties in murine atria due to their small size. This protocol describes the electrophysiological evaluation of atria using an optical mapping system with a high temporal and spatial resolution in Langendorff perfused murine hearts. The optical mapping system is assembled with dual high-speed complementary metal oxide semiconductor cameras and high magnification objective lenses, to detect the fluorescence of a voltage-sensitive dye and Ca2+ indicator. To focus on the assessment of murine atria, optical mapping is performed with an area of 2 mm &#215; 2 mm or 10 mm x 10 mm, with a 100 &#215; 100 resolution (20 &#181;m/pixel or 100 &#181;m/pixel) and sampling rate of up to 10 kHz (0.1 ms) at maximum. A 1-French size quadripolar electrode pacing catheter is placed into the right atrium through the superior vena cava avoiding any mechanical damage to the atrium, and pacing stimulation is delivered through the catheter. An electrophysiological study is performed with programmed stimulation including constant pacing, burst pacing, and up to triple extrastimuli pacing. Under a spontaneous or pacing rhythm, the optical mapping recorded the action potential duration, activation map, conduction velocity, and Ca2+ transient individually in the right and left atria. In addition, the programmed stimulation also determines the inducibility of atrial tachyarrhythmias. Precise activation mapping is performed to identify the propagation of the excitation in the atrium during an induced atrial tachyarrhythmia. Optical mapping with a specialized setting enables a thorough electrophysiological evaluation of the atrium in murine pathological models.

This protocol describes the electrophysiological evaluation of murine atria utilizing an optical mapping system with a high temporal and spatial resolution, including dual recordings of the membrane voltage and Ca2+ transient under programmed stimulation through a specialized electrode catheter.

高分辨率光学制图对小鼠心房电生理的评价

Recent genome-wide association studies targeting atrial fibrillation (AF) have indicated a strong association between the genotype and ...

Contractions of Human-iPSC-derived Cardiomyocyte Syncytia Measured with a Ca-sensitive Fluorescent Dye in Temperature-controlled 384-well Plates

Spontaneously contracting syncytia of cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CM) are a useful model of human cardiac physiology and pharmacology. Various methods have been proposed to record this spontaneous activity and to evaluate drug effects, but many of these methods suffer from limited throughput and/or physiological relevance. We developed a high-throughput screening system to quantify the effects of exogenous compounds on hiPSC-CM's beating frequency, using a Ca-sensitive fluorescent dye and a temperature-controlled imaging multi-well plate reader. We describe how to prepare the cell plates and the compound plates and how to run the automated assay to achieve high sensitivity and reproducibility. We also describe how to transform and analyze the fluorescence data to provide reliable measures of drug effects on spontaneous rhythm. This assay can be used in drug discovery programs to guide chemical optimization away from, or toward, compounds affecting human cardiac function.

Spontaneously contracting syncytia of cardiomyocytes derived from human-induced pluripotent stem cells are useful models of human cardiac physiology and pharmacology. Here we present a high-throughput screening system to quantify the effects of exogenous compounds on beating frequency, using a Ca-sensitive fluorescent dye and a temperature-controlled imaging multi-well plate reader.

温度控制384孔板中用 Ca 敏感荧光染料测定人 iPSC 的心肌细胞较多的收缩

Spontaneously contracting syncytia of cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CM) are a useful model of human cardiac ...

Digital Handwriting Analysis of Characters in Chinese Patients with Mild Cognitive Impairment

An increasing amount of evidence shows that cognitive deficits and movement dysfunctions are not separated. Patients with mild cognitive impairment (MCI) can manifest fine motor disorders of the upper extremities. Handwriting is a complex and unique human activity involving both motor and cognitive coordination. Researchers from western countries have discovered that patients with MCI have abnormal handwriting features. However, no relevant studies have been conducted in the Chinese population. Owing to the cross-culture phenomenon of handwriting, the aim of this study is to find new handwriting tasks to demonstrate the differences in handwriting features between elderly patients with MCI and age-matched healthy individuals.

This study proposed a digital handwriting analysis of characters in individuals with mild cognitive impairment to find more information than is revealed by traditional pencil&#8211;paper handwriting analysis.

中国轻度认知障碍患者人物数字笔迹分析

An increasing amount of evidence shows that cognitive deficits and movement dysfunctions are not separated. Patients with mild cognitive impairment (MCI) ...

A Standardized Approach to Extra-Oral and Intra-Oral Digital Photography

Contemporary dentistry mandates a more comprehensive and personalized analysis of each patient. Technological advances in digital photography have played vital roles in diagnostic accuracy, treatment planning, execution of therapies, and outcome evaluations, including esthetic enhancement. Digital photography also provides an excellent platform for patient education, communication, and co-management of cases with other healthcare providers. However, intra-oral photography often faces challenges such as inaccessibility of areas to be captured, different moveable vs. fixed tissues involved, contamination with saliva or blood, and differing illumination needs on various locations. Thus, a more standardized and systematic approach is proposed for intra- and extra-oral documentation via digital photography to overcome the existing technical challenges. The current work will outline the appropriate equipment specifications (camera bodies, macro lens, and flashes), positions and postures of the operator and patients, proper techniques of tissue retraction, the use of appropriate intra-oral mirrors, and the essential elements such as aperture settings (F-stop), ISO, shutter speed, and white balance. This article aims to provide all dental professionals with an approachable linear array of guidelines to produce simplified and standardized visual tools for more efficient and effective documentation.

The present protocol describes a method to capture intra- and extra-oral photographs for digital documentation in the clinical practice of dentistry. The protocol highlights all the critical components involved and the commonly utilized settings to capture dental photographs for clinical documentation.

口腔外和口腔内数码摄影的标准化方法

Contemporary dentistry mandates a more comprehensive and personalized analysis of each patient. Technological advances in digital photography have played ...

Detection and Removal of Tooth-Colored Composite Resin Using the Fluorescence-Aided Identification Technique

The detection and removal of tooth-colored filling materials is a major challenge for every dentist. The Fluorescence-aided Identification Technique (FIT) is a noninvasive tool to facilitate the distinction of composite resin material from sound tooth substance. Compared to conventional illumination, FIT is a very accurate, reliable, and fast diagnostic method. When composite resin is illuminated with a wavelength of approximately 398 &plusmn; 5 nm, certain fluorescent components make the composite resin appear brighter than the tooth structure. Any fluorescence-inducing light source with the appropriate wavelength can be used for this method. Optimally, this technique is used without additional natural or artificial lighting. The application of FIT can be used for diagnostic purposes, for example, dental charts, and additionally for the complete and minimally invasive removal of composite resin restorations, bracket debonding, and trauma splint removal. The assessment of volumetric changes after composite removal can be provided by overlapping pre- and postoperative scans and subsequent calculation using suitable software.

The Fluorescence-aided Identification Technique is a practicable, fast, and reliable approach for the differentiation of composite resin restorations from tooth substance, and facilitates the minimally invasive and complete removal of composite resin restorations and composite bonded trauma splints.

使用荧光辅助识别技术检测和去除牙齿颜色的复合树脂

The detection and removal of tooth-colored filling materials is a major challenge for every dentist. The Fluorescence-aided Identification Technique (FIT) ...

Dynamic Navigation in Endodontics: Guided Access Cavity Preparation by Means of a Miniaturized Navigation System

In the case of teeth with pulp canal calcification (PCC) and apical pathology or pulpitis, root canal treatment can be very challenging. PCC are common sequelae of dental trauma but can also occur with stimuli such as caries, bruxism, or after placing a restoration. In order to access the root canal as minimally invasive as possible in case of a necessary root canal treatment, dynamic navigation has recently been introduced in endodontics in addition to static navigation. The use of a dynamic navigation system (DNS) requires pre-operative cone-beam computed tomography (CBCT) imaging and a digital surface scan. If necessary, reference markers must be placed on the teeth before the CBCT scan; with some systems, these can also be planned and created digitally afterward. By means of a stereo camera connected to the planning software, the drill can now be coordinated with the help of reference markers and virtual planning. As a result, the position of the drill can be displayed on the monitor in real-time during preparation in different planes. In addition, the spatial displacement, the angular deviation, and the depth position are also displayed separately. The few commercially available DNS mostly consist of relatively large camera-marker-systems. Here, the DNS contains miniaturized components: a low-weight camera (97 g) mounted on the micromotor of the electric handpiece utilizing a manufacturer-specific connecting mechanism and a small marker (10 mm x 15 mm), which can be easily attached to an individually manufactured intraoral tray. For research purposes, a post-operative CBCT scan can be matched with the pre-operative one, and the volume of tooth structure removed can be calculated by the software. This work aims to present the technique of guided access cavity preparation by means of a miniaturized navigation system from imaging to clinical implementation.

Dynamic navigation systems (DNS) provide real-time visualization and guidance to the operator during endodontic access cavities preparation. The planning of the procedure requires three-dimensional imaging utilizing cone beam computed tomography and surface scans. After the export of the planning data to the DNS, access cavities can be prepared with minimal invasion.

牙髓病学中的动态导航：通过小型化导航系统进行引导通路腔准备

In the case of teeth with pulp canal calcification (PCC) and apical pathology or pulpitis, root canal treatment can be very challenging. PCC are common ...

使用数字叠加评估上颌后牙移动

Measuring Maxillary Posterior Tooth Movement: A Model Assessment using Palatal and Dental Superimposition

Since the introduction of Invisalign by Align Technology, Inc. in 1999, questions and debates have persisted regarding the precision of Invisalign (clear aligner) therapy, particularly when compared to the use of traditional fixed appliances. This becomes particularly significant in cases involving anteroposterior, vertical, and transverse corrections, where precise comparisons are of paramount importance. To address these inquiries, this study introduces a meticulously devised protocol, placing a primary emphasis on digitally superimposing the movement of maxillary posterior teeth to facilitate accurate analysis. The sample included 25 patients who had completed their first series of Invisalign (clear) aligners. Four maxillary digital models (pre-treatment, post-treatment, ClinCheck-initial, and final models) were digitally superimposed using the palate rugae and dentitions as stable references. A software combination was used for model superimposition and tooth segmentation. Transformation matrices then expressed the differences between the achieved and predicted tooth positions. Thresholds for clinically relevant differences were at &plusmn;0.25 mm for linear displacement and &plusmn;2&#176; for rotation. Differences were assessed using Hotelling's T-squared tests with Bonferroni correction. The mean differences in rotation (2.036&#176; &plusmn; 4.217&#176;) and torque (-2.913&#176; &plusmn; 3.263&#176;) were significant statistically and clinically, with p-values of 0.023 and 0.0003 respectively. De-rotation of premolars and torque control for all posterior teeth were less predictable. All mean differences for the linear measurements were statistically and clinically insignificant, except that the first molars seemed slightly (0.256 mm) more intruded than their predicted position. The clear aligner system appears to meet its prediction for most translational tooth movements and mesial-distal tipping in maxillary posterior teeth for non-extraction cases with mild to moderate malocclusions.

作者聚焦：透明矫正器治疗中上颌后牙的 3D 移动评估

This manuscript presents a comprehensive protocol to evaluate the three-dimensional (3D) movement of maxillary posterior teeth with clear aligners using digital model superimposition, an invaluable tool in orthodontics and dentofacial orthopedics.

测量上颌后牙运动：使用腭和牙齿叠加的模型评估

Since the introduction of Invisalign by Align Technology, Inc. in 1999, questions and debates have persisted regarding the precision of Invisalign (clear ...