作者希望感谢所有使这项工作成为可能的同事, 特别是 Drs. 阿迪亚齐柏和拉文答腊。作者感谢北京大学生物动态 & 生物工程实验室在康涅狄格健康方面所提供的设施在这个项目的发展。

1. 实验设置
<ol><li>使用定制的 "夹具", 标记在 OWT 铝钉上放置磨牙管和门牙托架的精确位置。</li>
	<li>粘结标准自结扎支架与复合材料。光治疗40秒。</li>
	<li>将 0.021 x 0.025 英寸不锈钢 (SS) ' 卵球形 ' 上颌弓插入支架插槽中。</li>
	<li>将测试仪器放在玻璃腔内。</li>
	<li>检查是否有任何意外的弓激活。任何激活的弓将自动创建一个力系统, 将显示在计算机屏幕上。</li>
	<li>如果观察到任何弓激活, 则重新定位托架。重复步骤 1.2-1.5。</li>
</ol>2. 制作模板弓 (图 4)
<ol><li>在测试仪器中放置一个弓 (0.021 x 0.025 SS)。</li>
	<li>使用永久性标记来指示以下内容: 1) 中线, 2) 一点, 紧靠门牙支架 (I) 和 3), 立即内侧到磨牙管 (M)。对弓的对侧也做同样的事。这是模板拱线。</li>
	<li>将弓与标记的点转移到图表纸上。</li>
	<li>在图形纸上制作弓的精确副本。 注: 此图纸可用于确定样品的所有矫正线的 V 形弯的位置。</li>
	<li>计算拱线段 (L) 从 I 到 m 的周长。</li>
	<li>现在, 马克11点从我到 m。每一点都是未来的 V 折弯位置。<ol>
<li>将每个点标记为0到10。</li>
		<li>请确保每个折弯位置与另一项之间的大小相等。</li>
	</ol>
</li>
	<li>通过计算每个位置的/L 为每个折弯位置获取唯一的数字/比率。</li>
</ol>3. V 型弯的放置
<ol><li>从样品中取一个新的弓。</li>
	<li>把它放在模板弓/图形纸上, 并将其中一个十一折弯位置双边地转移到弓。</li>
	<li>使用矩形弓钳或轻钢丝钳, 使对称的 V 弯在两个位置。</li>
	<li>将弓放在玻璃板/平面平台上, 并检查弓两端与量角器的角度测量。</li>
	<li>如果需要, 调整两端, 以便创建150°的角度。</li>
	<li>对示例的所有矫正线重复步骤3.1 到3.5。</li>
</ol>4. 测量力系统 (图5和 6)
<ol><li>打开用于数据记录的软件程序 (参见材料表)。</li>
	<li>为要保存的数据创建一个新文件夹。</li>
	<li>单击 "运行" 启动软件。该程序将在每个传感器上实时显示三个力和三力矩值。</li>
	<li>等待大约10-15 秒的数据记录软件的波动停止。确保该软件上的图形线为部队系统的所有组件显示 "平坦" 线。 注: 所有六测量在每个传感器将显示微不足道的价值 (力量 < 1 g 和时刻 < 10 g 毫米)。</li>
	<li>从平台上轻轻地移除 "测试设备"。使用 Weingart 钳将弓插入到摩尔管中。</li>
	<li>用牙周洁打开门牙支架的门。</li>
	<li>提起弓的前部, 并将其插入托架插槽中。确保弓中线与测试仪器的中线重合。</li>
	<li>将测试仪器返回平台并关闭玻璃室的门。</li>
	<li>将温度设置为摄氏37摄氏度。等待一分钟的温度, 玻璃室调整。</li>
	<li>单击软件上的 "开始保存" 按钮, 并允许软件保存/传输数据至少10秒。再次单击 "开始保存" 按钮以结束数据传输, 然后单击 "停止"。 注: 每个测量周期在10秒内为每个组件 (fx、fy、fz、mx、my和 mz) 生成100读数。</li>
	<li>转到包含已保存数据的文档, 并将数据集复制/导出到自定义设计的数据分析电子表格 (请参阅辅助表)。选择正确的 V 形折弯位置编号和特定导线样本以插入数据。</li>
	<li>对该特定折弯位置的10矫正线重复步骤4.3 到4.11。</li>
	<li>现在, 将矫正线的计算方法和标准偏差复制到单独的电子表格中, 以创建数据的图形表示形式。</li>
	<li>对所有折弯位置和矫正线类型重复步骤4.2 到4.13。 注: 矫正线包括不锈钢 (SS) 和β钛 (ß钛), 具有以下尺寸: 0.016 x 0.022 英寸, 0.017 x 0.025 英寸, 0.019 x 0.025 英寸。</li>
</ol>5. 错误评估
<ol><li>按照步骤 4.1-4.4 中的说明运行计算机/软件</li>
	<li>从平台上取出 "测试设备"。</li>
	<li>获得一个直长 0.021 x 0.025 英寸 SS 线。使用轻线钳, 弯曲线的一端成一个小钩。将弓的游离端插入从远端的摩尔管中。</li>
	<li>将测试仪器放回平台上。</li>
	<li>将已知重量 (50 克) 附加到挂钩上。让它在垂直平面上自由悬挂, 消除任何类型的干扰。关上玻璃室的门。</li>
	<li>执行步骤 4.10-4. 11。</li>
	<li>对切牙支架重复步骤 5.1-5.6。</li>
	<li>输入作为 "测量值" 的摩尔管的托架和 Mx 的熔体值。</li>
	<li>现在应用平衡等式 (参见补充文本) 计算 "预期值"。</li>
</ol>

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作者没有什么可透露的。

正畸矫正线已研究了不同的方式8,9,10,11。他们也被评估了各种机械性能, 但他们很少被分析, 以确定的力量系统, 他们将创建12,13,14,15。三点弯曲试验普遍用于评价正畸矫正线;然而, 它们通常是在没有任何弯曲的直导线上进行的。体外评估通常是优化, 以观察只有1或2个变量的时候, 不允许的结果是容易适应的临床情况。本研究的重点是试验性地确定由垂直 V 形弯曲所产生的3D 力系统, 在 interbracket 距离上放置在不同位置的矩形矫正线作为 2 x 4 装置。此协议与以前分析 V 形弯曲力学的方法有很大区别。这是第一次建立一个实际的体外设置是利用纳米传感器模仿工作的两个支架-弓几何, 而不是依赖于计算机模型或有限元方法。这个机械模型不仅测量弯矩 (第二阶导线支架相互作用), 而且扭矩 (三阶导线支架相互作用)。不施加边界条件。换句话说, 以前的研究从来没有考虑到弓的曲率, 因为它从磨牙到门牙的支架。由于这一曲线, 切牙和摩尔括号没有定位在同一平面上, 也不是平行于彼此。这种安排可以增加对力系统的分析的复杂性, 这使得他们在临床上比仅涉及两个相同的括号排列在一条直线和平行3,4更相关。
传感器的功能和数据输出可以很容易地影响的因素, 如设备的误差, 传感器灵敏度, 过热的 OWT, 人为错误的电线活化, 弯曲, 结扎, 形状, 不当的导线定位, 失活的导线在最后插入之前, 变形弓等, 因此, 用新的矫正线进行重复测量, 并运用平衡定律验证数据是很重要的。此外, 只有少数矫正线应插入测量, 以避免过热的 OWT。
每个折弯位置仅由3.7 毫米分开。因此, 准确地放置 V 型弯沿弓也是重要的。小偏差从期望的位置可能从根本上改变被记录的力量系统。一种自定义的图形纸, 包含带有 V 形弯曲位置的弓模板, 有助于达到所需的精度。铝钉上的托架定位不当也可以做同样的事。因此, 如果出现粘结故障, 则使用定制的精密夹具来获得支架的位置。
在实验过程中, 如果支架得到脱胶, 一个新的支架必须精确地放回同一位置。定制设计的夹具可以帮助找到所需的位置。无任何弯曲的被动矫正线必须用于确保支架的位置正确。如果没有, 它将不得不 rebracketed。重要的是不要重用脱胶支架, 因为有增加的可能性的支架变形。
当前方法的一个缺点是, 仅使用了两个传感器。增加更多的传感器将允许研究更复杂的力系统, 如那些包括三或更多的支架设置在拱。另一个潜在的缺点是无法模拟口腔环境。温度、唾液、闭塞等因素可能会影响产生的力系统。然而, 在这一点上是不可能同时测量的力量系统和观察到的牙齿运动在临床水平。
使用有限元分析 (FEM) 的计算机建模和模拟是一个快速出现的区域, 用于解码各种正畸器具的生物力学16、17、18、 19. 然而, 验证这些方法的一个先决条件是精确地将复杂的弓支架相互作用结合在一起, 并将假设保持在最低限度。在第二阶和第三阶中, 弓支架的相互作用很大程度上是未知的, 这可能会限制这些程序的准确性。为了更好地进行计算机模拟, 首先要找出在各种临床情况下存在的力系统, 生成一个相当可观的生物力学数据库, 然后建立一个基于该数据集的计算机模型。换言之, 更好的建模和预测将需要本协议提供的实际实验。

临床正畸治疗的一个重要方面是了解 multibracket 装置产生的力系统。明确了解基本的生物力学原理有助于提供可预测的结果, 并尽量减少潜在的副作用1。近年来, 随着支架位置和设计的增加, 在矫正线中放置弯曲的趋势越来越远;然而, 综合正畸治疗仍需要在矫正线中放置弯曲。弯曲, 当放置在不同的类型和大小的矫正线, 可以创建各种力量系统, 适合不同类型的牙齿运动。虽然在考虑多齿时, 力系统会变得相当复杂, 但一个有用的起点可能涉及简单的双支架系统。
迄今为止, V 型弯曲力学主要是在第二阶分析, 利用数学模型1,2,3,4,5和/或基于计算机的分析/模拟6. 这已经对涉及相邻支架的拱导线的二阶相互作用所涉及到的力系统有了基本的理解 (图 1)。然而, 这些方法施加一定的边界条件, 以运行模拟, 可能不会在实际的临床情况下, 可能会发生偏差。最近, 提出了一种新的体外模型, 涉及力传感器, 以测量三维 (3D) 的力量和创造的时刻, 不仅评估第二级弓支架相互作用, 但也在第三级7。然而, 不同类型的矫正线对沿切牙磨牙弓的不同弯曲位置的力系统的影响没有得到评价。此外, 这项研究仅涉及弹性正畸矫正线的评价, 这不是牙齿运动发生的主要矫正线。因此, 本研究的目的是评估在不同位置的方形不锈钢和β钛矫正线在一个3D 设置涉及磨牙和切牙支架所产生的力系统。临床医生需要知道的力量系统应用于牙列时, 具体组合的弓支架组合被用来修复错用。
本文研究了三平面空间的正畸力系统, 模仿临床实际。据了解, 临床上测量力系统是极其困难的;因此, 这种测量必须在体外进行。假设在实验室中由 V 形弯曲产生的力系统在病人口中被复制是相似的。创建了一个工作流来评估如何配置实验设置 (图 2)。
正畸钢丝测试仪 (OWT) 是一种创新产品, 由正畸的分工与生物工程 & 北京大学生物动态实验室, 康涅狄格健康, 法明顿, CT, 美国 (图 3) 合作开发。它的目的是准确模仿上颌牙齿的安排, 在口腔内和一些内部的条件, 同时提供测量的力量系统创建的所有三平面空间。OWT 的主要机械部件是数据采集装置 (数据采集器)、纳米力/扭矩传感器、湿度传感器、温度传感器和个人电脑。测试装置放置在具有温度/湿度控制的玻璃外壳内。这允许部分模拟口腔内环境。该数据采集器作为三传感器的接口: 湿度传感器、力/力矩传感器、热敏电阻以及位于平台上的传感器的测试设备 (图 3)。这些链接与一个软件程序。软件是可视化编程的平台和开发环境, 用于控制不同类型的硬件。它被选择自动化的正畸线测试仪。
在检测仪器上设置了一系列铝钉, 以表示上颌牙弓的牙齿。两个代表右中央切牙和右第一磨牙的钉子连接到传感器/负载单元 (S1 和 S2)。负载单元是一种机械装置, 可以测量所有三个平面 (x-y) 中应用到它的力和力矩: fx、fy和 fz;mx, my, 和 mz。该钉是有系统地定位, 以创建牙科弓形式。每一个 peg 是由一个精确记录的测量分离, 用平均牙齿宽度计算, 在患者正畸治疗。为实验选择的形状是由标准模板创建的 "卵球形" 拱形式。

<table border="0" cellpadding="0" cellspacing="0" style="width:1011px;" width="1011">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:248px;">Force/Torque&#160; Sensors/Transducers</td>
			<td style="width:488px;">Nano17 F/T Sensors,&#160; ATI Industrial Automation, Apex, NC, USA</td>
			<td style="width:115px;"></td>
			<td style="width:160px;">Part of the OWT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CHS Series Humidity&#160; Sensor Units</td>
			<td>&#160; TDK Corporation</td>
			<td></td>
			<td>Part of the OWT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Temperature sensors</td>
			<td>(Murata NTSDXH103FPB30 thermistor) Murata Manufacturing Co., Ltd</td>
			<td></td>
			<td>Part of the OWT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LabVIEW 7.1.&#160;</td>
			<td>Laboratory Virtual Instrumentation Engineering Workbench, Version 7.1</td>
			<td></td>
			<td>Software Program</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Self-Ligating brackets&#160;</td>
			<td>Empower Series, American Orthodontics.</td>
			<td></td>
			<td>Orthodontic Brackets</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stainless steel archwires</td>
			<td>Ultimate Wireforms, Inc. in Bristol, CT</td>
			<td></td>
			<td>Archwires</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Beta-Titanium Archwires</td>
			<td>Ultimate Wireforms, Inc. in Bristol, CT</td>
			<td></td>
			<td>Archwires</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Data acquisition device (DAQ)</td>
			<td>National Instruments (NI) USB 6210</td>
			<td></td>
			<td>Part of the OWT</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ortho Form III (Archform template)</td>
			<td>3M Oral Care, St. Paul, MN, USA</td>
			<td></td>
			<td>Ovoid arch form</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Weingart Plier</td>
			<td>Hu-Friedy Mfg. Co., LLC Chicago, IL</td>
			<td></td>
			<td>Orthodontic Plier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Light wire Plier</td>
			<td>Hu-Friedy Mfg. Co., LLC Chicago, IL</td>
			<td></td>
			<td>Orthodontic Plier</td>
		</tr>
	</tbody>
</table>

force system with vertical v-bends: a 3d in vitro assessment of elastic and rigid rectangular archwires

正确理解各种正畸器械所产生的力系统, 可以使病人的治疗效率和可预测性。将复杂的多支架装置减少到简单的双支架系统, 以进行力系统评估, 将是朝这个方向迈出的第一步。然而, 这方面的正畸生物力学大部分限于2D 实验研究, 计算机建模/分析或理论外推现有模型。本协议的目的是设计、构造和验证一种体外3D 模型, 能够测量在两个支架之间放置 V 形弯曲的弓产生的力和力矩。另外的目标是比较不同类型的矫正线在他们自己和以前的模型中产生的力系统。为此, 我们模拟了一个 2 x 4 装置, 代表一个臼齿和一个门牙。正畸导线测试仪 (OWT) 是由两个多轴力传感器或负载细胞 (纳米传感器) 构成的, 正畸支架连接。负载单元能够测量所有三平面空间中的力系统。测试了两种类型的矫正线, 不锈钢和β钛三不同大小 (0.016 x 0.022 英寸, 0.017 x 0.025 英寸和 0.019 x 0.025 英寸)。每根导线接受一个垂直的 V 弯被系统地安置在一个特定位置以预定义的角度。类似的 V 形弯曲在不同的矫正线上复制, 在11个不同的位置之间的磨牙和切牙附件。这是第一次在体外尝试使用 V 形弯曲对不同矫正线的正畸装置进行模拟。

传感器板中心的每个传感器所经历的总力和总力矩由其三个正交分量表示: fx、fy和 z 轴, 表示沿 x 轴、y 轴和 z 轴线的作用力,分别mx, my, mz表示在同一轴周围的时刻。传感器的初始测量将数学转换为支架所经历的力和力矩值 (图 7)。
一系列图表显示垂直力在摩尔 (熔米) 和切牙托架 (熔i), 力矩 (牙冠小费) 在摩尔支架 (mxm), 力矩/扭矩 (labio 舌小费) 在门牙支架 (mxi) 相对于从原始数据中创建的与单个齿坐标系相关的一/升比率。牙冠比表示每个 V 形弯曲的位置, 其中 ' a ' 是切牙支架的远端边缘和 V 形弯的顶端之间的距离, 和 ' L ' 的摩尔管的内侧边缘和切牙托架的远端边缘之间的距离easured 沿弓 (37 毫米)。a/升比率为 0.0 (0 毫米/37 毫米) 表示与门牙支架相邻的折弯, 每一个连续的弯曲 (a/l = 0.1, 0.2等) 的间距3.7 毫米远离上一个折弯结束与/升 = 1.0 (37 mm/37 毫米), 代表一个弯曲相邻的摩尔括号。力系统的方向由一个负/正符号表示。图表按导线类型和大小分组 (图 9和 10)。图上的每个点都表示十相似矫正线的平均值, 误差线表示上述平均值的一个标准偏差。靠近水平轴的点 (上面或下方) 表示具有低震级的力或力矩, 而从水平轴 (上方或下方) 远一点的点表示具有较高震级的力或力矩。
垂直力 (FZ) 显示六线类型的对称和线性模式 (图 8)。接近 V 弯到任一支架, 更高是垂直力量。当折弯从支架上移开, 向中心移动时, FZ的大小减小, 直到到达某一点时, 两个力都近似为零 (中性区)。当弯向更远的位置移动, FZ逐渐增加。然而, 个别力 (f 和 f子)的方向是颠倒的。定量地, SS 矫正线创造了一个明显地更大的力量系统比ß-Ti 矫正线。此外, 更高维度矫正线创建更大的力系统。令人惊讶的是, 矫正线在两个支架上创建的相对力系统在弓的大小和类型方面都相当相似。
相反, 矩 (MX) 显示了非线性和非对称模式 (图 9)。当 V 弯被放置在接近的摩尔管 (x/升比率 > 0.6), 以及在摩尔管 (红色) 的力矩方向逆转从x/升的0.0 到 0.2, 是类似于所有矫正线, 也许代表弓支架相互作用和支架方向 (二阶与第三阶) 的一个更基本的性质。在两个托架上的矩比率显示了在所有矫正线测试中观察到的特定模式 (图 10)。弯曲, 被放置在接近门牙 (0.0-0.3 为ß和 0.0-0.2 为 SS) 有两个时刻在同一方向 (mxi/mxm > 0)。从 0.3-0.6 的ß和 0.3-0.4 的 a/升为 SS, 瞬间是相反的方向 (mxi/mxm < 0) (中性区)。弯曲在0.6 或更大没有创造一个重要时刻在门牙 (≈0 g 毫米), 但一个巨大的片刻在摩尔管 (mxi/mxm≈0) 产生。
定量地, 再和垂直力一样, SS 弓所产生的力矩的大小在统计学上和临床上都大于ß-Ti 矫正线产生的, 无论是升比还是拱线的大小。
百分比错误由以下等式计算:
<img alt="Figure 1" src="/files/ftp_upload/57339/57339eq1.jpg">
小于50克的权重的% 误差被发现为 5%, 从50到500克的权重计算为0.5%。
中性区 (相等和相反弯矩) 被发现在 0.3-0.4 的ß比率为 SS 矫正线和 0.4-0.5。在这些特定的弯曲位置, 垂直力是最小的时刻作用在切牙和摩尔括号对面的方向。根据 a/d 比率, 在磨牙和切牙支架之间由 V 形弯曲产生的力系统可分为三种不同的类别 (图 11)。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57339/57339fig1.jpg"> 图 1: 在第二个顺序中由两个共线托架创建的强制系统.L 是两个括号之间的距离;a 是 V 形弯从支架 a 的位置;fa和 fb是分别在支架 A 和 b 上产生的垂直力;Ma是片刻在 a;Mb是括号 b 的时刻.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig1large.jpg" target="_blank">请点击这里查看这个数字的大版本</a>。
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57339/57339fig2.jpg"> 图 2: 工作流.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57339/57339fig3.jpg"> 图 3: 正畸钢丝测试仪 (OWT).A: 检测仪器, B: 测量平台, C: 温度监测器。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57339/57339fig4.jpg"> 图 4: 两个附件之间的折弯位置的示意图表示形式.每一个蓝色点是一个折弯位置, 代表距离 ' a ' 测量从切牙支架沿弓。将有11个不同的值为 ' a ' 的增量为3.7 毫米. (即蓝点与相邻的蓝点分开3.7 毫米)。L 是从切牙支架远端表面到沿弓的摩尔管远端表面测量的周长长度。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57339/57339fig5.jpg"> 图 5: 弓插入和持有的支架上的铝钉连接到传感器.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57339/57339fig6.jpg"> 图 6: 显示原始数据 (蓝色和红色盒) 的软件程序, 从连接到门牙和臼齿托架的两个传感器 (S1 和 S2) 获得.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/57339/57339fig7.jpg"> 图 7: X Y Z 坐标及其与 OWT 的方向关系.X: 横向平面;水平平面;Z: 垂直平面。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/57339/57339fig8.jpg"> 图 8: 垂直力 (熔) 在两个托架上的图形表示.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig8large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/57339/57339fig9.jpg"> 图 9: 在两个托架上的横向平面 (Mx) 中的矩的图形表示.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig9large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/57339/57339fig10.jpg"> 图 10: 相对力系统横跨不同的弓类型和大小通过时刻的比率描述 [Mx (i)/mx (m)].<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig10large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/57339/57339fig11.jpg"> 图 11: 三不同的力量系统从 V 弯.每个区域代表一个唯一的 f# 系统。"蓝色" 阴影区域描述了与类似的相对力系统的 a/d 比率。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339fig11large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td>力系统</td>
			<td>摩尔 (m)</td>
			<td>切牙 (i)</td>
		</tr>
<tr>
<td>熔 (+)</td>
			<td>侵入</td>
			<td>侵入</td>
		</tr>
<tr>
<td>熔 (-)</td>
			<td>突出</td>
			<td>突出</td>
		</tr>
<tr>
<td>Mx (+) *</td>
			<td>内侧提示</td>
			<td>面部/唇尖</td>
		</tr>
<tr>
<td>Mx (-) *</td>
			<td>远端尖端</td>
			<td>腭/舌尖</td>
		</tr>
<tr>
<td colspan="3">* 所有测量均在支架上进行</td>
		</tr>
</tbody></table>表 1: 签署了部队系统的公约和方向。
<img alt="Figure 1" src="/files/ftp_upload/57339/57339supfig1.jpg"> 补充图 1: x 轴周围力矩的平衡图 (Mx).注意: 图只是比较矩的大小。mx(m) + Mx(i)和 fz(m)或 fz(i) x D 的方向将始终是相反的。因此, ΣMx= 0 (参见补充文本)。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/57339supfig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
补充案文. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57339/Supplementary_text.docx" target="_blank">请单击此处下载此文件.</a>

Watch this Scientific Journal Video about Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires at JoVE.com

Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires

本文提出的方法是建立和验证体外3D 模型, 能够测量由两个支架之间放置的 V 形弯曲的不同矫正线所产生的力系统。另外的目标是比较这个力系统与不同类型的矫正线和以前的模型。

垂直 V 形弯曲力系统: 3D 弹性和刚性矩形矫正线的体外评价

A proper understanding of the force system created by various orthodontic appliances can make treatment of patients efficient and predictable. Reducing ...

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Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires

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10.5K 次观看.  University of Connecticut Health. 本文提出的方法是建立和验证体外3D 模型, 能够测量由两个支架之间放置的 V 形弯曲的不同矫正线所产生的力系统。另外的目标是比较这个力系统与不同类型的矫正线和以前的模型。

视频: Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires

Tissue Engineering of a Human 3D in vitro Tumor Test System

Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system.	
	Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line. For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns).	
	Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow.	
	In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.

Tissue Engineering of a Human 3D in vitro Tumor Test System

Methods to create human 3D tumor tissues as test systems are described. These technologies are based on a decellularized Biological Vascularized Scaffold (BioVaSc), primary human cells and a tumor cell line, which can be cultured under static as well as under dynamic conditions in a flow bioreactor.

一个人的3D组织工程<em&gt;在体外</em&gt;肿瘤测试系统

Cancer is one of the leading causes of death worldwide.  Current therapeutic strategies are predominantly developed in 2D culture  systems, which ...

科研

生物工程

Insertion of Flexible Neural Probes Using Rigid Stiffeners Attached with Biodissolvable Adhesive

Microelectrode arrays for neural interface devices that are made of biocompatible thin-film polymer are expected to have extended functional lifetime because the flexible material may minimize adverse tissue response caused by micromotion. However, their flexibility prevents them from being accurately inserted into neural tissue. This article demonstrates a method to temporarily attach a flexible microelectrode probe to a rigid stiffener using biodissolvable polyethylene glycol (PEG) to facilitate precise, surgical insertion of the probe. A unique stiffener design allows for uniform distribution of the PEG adhesive along the length of the probe. Flip-chip bonding, a common tool used in microelectronics packaging, enables accurate and repeatable alignment and attachment of the probe to the stiffener. The probe and stiffener are surgically implanted together, then the PEG is allowed to dissolve so that the stiffener can be extracted leaving the probe in place. Finally, an in vitro test method is used to evaluate stiffener extraction in an agarose gel model of brain tissue. This approach to implantation has proven particularly advantageous for longer flexible probes (&gt;3 mm). It also provides a feasible method to implant dual-sided flexible probes. To date, the technique has been used to obtain various in vivo recording data from the rat cortex.

Insertion of flexible neural microelectrode probes is enabled by attaching probes to rigid stiffeners with polyethylene glycol (PEG). A unique assembly process ensures uniform and repeatable attachment. After insertion into tissue, the PEG dissolves and the stiffener is extracted. An in vitro test method evaluates the technique in agarose gel.

柔性神经微探针的使用附加与Biodissolvable胶粘剂刚性加劲肋插入

Microelectrode  arrays for neural interface devices that are made of biocompatible thin-film  polymer are expected to have extended functional lifetime ...

Investigating Receptor-ligand Systems of the Cellulosome with AFM-based Single-molecule Force Spectroscopy

Cellulosomes are discrete multienzyme complexes used by a subset of anaerobic bacteria and fungi to digest lignocellulosic substrates. Assembly of the enzymes onto the noncatalytic scaffold protein is directed by interactions among a family of related receptor-ligand pairs comprising interacting cohesin and dockerin modules. The extremely strong binding between cohesin and dockerin modules results in dissociation constants in the low picomolar to nanomolar range, which may hamper accurate off-rate measurements with conventional bulk methods. Single-molecule force spectroscopy (SMFS) with the atomic force microscope measures the response of individual biomolecules to force, and in contrast to other single-molecule manipulation methods (i.e.&#160;optical tweezers), is optimal for studying high-affinity receptor-ligand interactions because of its ability to probe the high-force regime (&#62;120 pN). Here we present our complete protocol for studying cellulosomal protein assemblies at the single-molecule level. Using a protein topology derived from the native cellulosome, we worked with enzyme-dockerin and carbohydrate binding module-cohesin (CBM-cohesin) fusion proteins, each with an accessible free thiol group at an engineered cysteine residue. We present our site-specific surface immobilization protocol, along with our measurement and data analysis procedure for obtaining detailed binding parameters for the high-affinity complex. We demonstrate how to quantify single subdomain unfolding forces, complex rupture forces, kinetic off-rates, and potential widths of the binding well. The successful application of these methods in characterizing the cohesin-dockerin interaction responsible for assembly of multidomain cellulolytic complexes is further described.

Cellulosomes are multienzyme complexes designed for digesting cellulose. AFM-based SMFS was used to study the mechanical properties and folding configuration of cellulosome-associated protein assemblies. We present a complete workflow for protein immobilization, data acquisition, and data analysis to study the interactions of individual receptor-ligand complexes involved in cellulosome assembly.

调查纤维素酶与基于AFM的单分子力谱受体 - 配体系统

Cellulosomes are discrete multienzyme complexes used by a subset of anaerobic bacteria and fungi to digest lignocellulosic substrates. Assembly of the ...

Planar Gradient Diffusion System to Investigate Chemotaxis in a 3D Collagen Matrix

The importance of cell migration can be seen through the development of human life. When cells migrate, they generate forces and transfer these forces to their surrounding area, leading to cell movement and migration. In order to understand the mechanisms that can alter and/or affect cell migration, one can study these forces. In theory, understanding the fundamental mechanisms and forces underlying cell migration holds the promise of effective approaches for treating diseases and promoting cellular transplantation. Unfortunately, modern chemotaxis chambers that have been developed are usually restricted to two dimensions (2D) and have complex diffusion gradients that make the experiment difficult to interpret. To this end, we have developed, and describe in this paper, a direct-viewing chamber for chemotaxis studies, which allows one to overcome modern chemotaxis chamber obstacles able to measure cell forces and specific concentration within the chamber in a 3D environment to study cell 3D migration. More compelling, this approach allows one to successfully model diffusion through 3D collagen matrices and calculate the coefficient of diffusion of a chemoattractant through multiple different concentrations of collagen, while keeping the system simple and user friendly for traction force microscopy (TFM) and digital volume correlation (DVC) analysis.

Cell migration is an important part of human development and life. In order to understand the mechanisms that can alter cell migration, we present a planar gradient diffusion system to investigate chemotaxis in a 3D collagen matrix, which allows one to overcome modern diffusion chamber limitations of existing assays.

平面梯度扩散系统的调查趋化三维胶原基质

The importance of cell migration can be seen through the development of human life. When cells migrate, they generate forces and transfer these forces to ...

Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and accurate assessment of ocular toxicity in man are needed. To address this need, we have developed an eye irritation test (EIT) which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model that is based on normal human cells. The EIT is able to separate ocular&#160;irritants and corrosives (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category). The test utilizes two separate protocols, one designed for liquid chemicals and a second, similar protocol for solid test articles. The EIT prediction model uses a single exposure period (30 min for liquids, 6 hr for solids) and a single tissue viability cut-off (60.0% as determined by the MTT assay). Based on the results for 83 chemicals (44 liquids and 39 solids) EIT achieved 95.5/68.2/ and 81.8% sensitivity/specificity and accuracy (SS&#38;A) for liquids, 100.0/68.4/ and 84.6% SS&#38;A for solids, and 97.6/68.3/ and 83.1% for overall SS&#38;A. The EIT will contribute significantly to classifying the ocular irritation potential of a wide range of liquid and solid chemicals without the use of animals to meet regulatory testing requirements. The EpiOcular EIT method was implemented in 2015 into the OECD Test Guidelines as TG 492.

Eye Irritation Test EIT for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial RhCE Tissue Model

We have developed an eye irritation test which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model. The test is able to discriminate between ocular irritant and corrosive materials (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category).

眼刺激试验（EIT）使用重构型人角膜上皮样（RHCE）组织模型眼刺激性化学品危险性鉴定

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and ...

Improving 2D and 3D Skin In Vitro Models Using Macromolecular Crowding

The glycoprotein family of collagens represents the main structural proteins in the human body, and are key components of biomaterials used in modern tissue engineering. A technical bottleneck is the deposition of collagen in vitro, as it is notoriously slow, resulting in sub-optimal formation of connective tissue and subsequent tissue cohesion, particularly in skin models. Here, we describe a method which involves the addition of differentially-sized sucrose co-polymers to skin cultures to generate macromolecular crowding (MMC), which results in a dramatic enhancement of collagen deposition. Particularly, dermal fibroblasts deposited a significant amount of collagen I/IV/VII and fibronectin under MMC in comparison to controls.
The protocol also describes a method to decellularize crowded cell layers, exposing significant amounts of extracellular matrix (ECM) which were retained on the culture surface as evidenced by immunocytochemistry. Total matrix mass and distribution pattern was studied using interference reflection microscopy. Interestingly, fibroblasts, keratinocytes and co-cultures produced cell-derived matrices (CDM) of varying composition and morphology. CDM could be used as &#34;bio-scaffolds&#34; for secondary cell seeding, where the current use of coatings or scaffolds, typically from xenogenic animal sources, can be avoided, thus moving towards more clinically relevant applications.
In addition, this protocol describes the application of MMC during the submerged phase of a 3D-organotypic skin co-culture model which was sufficient to enhance ECM deposition in the dermo-epidermal junction (DEJ), in particular, collagen VII, the major component of anchoring fibrils. Electron microscopy confirmed the presence of anchoring fibrils in cultures developed with MMC, as compared to controls. This is significant as anchoring fibrils tether the dermis to the epidermis, hence, having a pre-formed mature DEJ may benefit skin graft recipients in terms of graft stability and overall wound healing. Furthermore, culture time was condensed from 5 weeks to 3 weeks to obtain a mature construct, when using MMC, reducing costs.

Improving 2D and 3D Skin In Vitro Models Using Macromolecular Crowding

We present a protocol to obtain cell-derived matrices rich in extracellular matrix proteins, using macromolecular crowders (MMC). In addition, we present a protocol which incorporates MMC in 3D organotypic skin co-culture generation, which reduces culture time while maintaining maturity of construct.

提高2D和3D皮肤<em&gt;体外</em&gt;模型使用大分子拥挤

The glycoprotein family of collagens represents the main structural proteins in the human body, and are key components of biomaterials used in modern ...

Improved 3D Hydrogel Cultures of Primary Glial Cells for In Vitro Modelling of Neuroinflammation

In the central nervous system, numerous acute injuries and neurodegenerative disorders, as well as implanted devices or biomaterials engineered to enhance function result in the same outcome: excess inflammation leads to gliosis, cytotoxicity, and/or formation of a glial scar that collectively exacerbate injury or prevent healthy recovery. With the intent of creating a system to model glial scar formation and study inflammatory processes, we have generated a 3D cell scaffold capable of housing primary cultured glial cells: microglia that regulate the foreign body response and initiate the inflammatory event, astrocytes that respond to form a fibrous scar, and oligodendrocytes that are typically vulnerable to inflammatory injury. The present work provides a detailed step-by-step method for the fabrication, culture, and microscopic characterization of a hyaluronic acid-based 3D hydrogel scaffold with encapsulated rat brain-derived glial cells. Further, protocols for characterization of cell encapsulation and the hydrogel scaffold by confocal immunofluorescence and scanning electron microscopy are demonstrated, as well as the capacity to modify the scaffold with bioactive substrates, with incorporation of a commercial basal lamina mixture to improved cell integration.

Improved 3D Hydrogel Cultures of Primary Glial Cells for In Vitro Modelling of Neuroinflammation

Herein, we present a protocol for the 3D culture of rat brain-derived glia cells, including astrocytes, microglia, and oligodendrocytes. We demonstrate primary cell culture, methacrylated hyaluronic acid (HAMA) hydrogel synthesis, HAMAphoto-polymerization and cell encapsulation, and sample processing for confocal and scanning electron microscopic imaging.

改良的3D 水凝胶培养的原发胶质细胞的体外Neuroinflammation 模型的建立

In the central nervous system, numerous acute injuries and neurodegenerative disorders, as well as implanted devices or biomaterials engineered to enhance ...

Rigid Embedding of Fixed and Stained, Whole, Millimeter-Scale Specimens for Section-free 3D Histology by Micro-Computed Tomography

For over a hundred years, the histological study of tissues has been the gold standard for medical diagnosis because histology allows all cell types in every tissue to be identified and characterized. Our laboratory is actively working to make technological advances in X-ray micro-computed tomography (micro-CT) that will bring the diagnostic power of histology to the study of full tissue volumes at cellular resolution (i.e., an X-ray Histo-tomography modality). Toward this end, we have made targeted improvements to the sample preparation pipeline. One key optimization, and the focus of the present work, is a straightforward method for rigid embedding of fixed and stained millimeter-scale samples. Many of the published methods for sample immobilization and correlative micro-CT imaging rely on placing the samples in paraffin wax, agarose, or liquids such as alcohol. Our approach extends this work with custom procedures and the design of a 3-dimensional printable apparatus to embed the samples in an acrylic resin directly into polyimide tubing, which is relatively transparent to X-rays. Herein, sample preparation procedures are described for the samples from 0.5 to 10 mm in diameter, which would be suitable for whole zebrafish larvae and juveniles, or other animals and tissue samples of similar dimensions. As proof of concept, we have embedded the specimens from Danio, Drosophila, Daphnia, and a mouse embryo; representative images from 3-dimensional scans for three of these samples are shown. Importantly, our methodology leads to multiple benefits including rigid immobilization, long-term preservation of laboriously-created resources, and the ability to re-interrogate samples.

We developed protocols and designed a custom apparatus to enable embedding of millimeter-scale specimens. We present sample preparation procedures with an emphasis on embedding in acrylic resin and polyimide tubing to achieve rigid immobilization and long-term storage of specimens for the interrogation of tissue architecture and cell morphology by micro-CT.

用微计算机断层扫描法对无节段3D 组织学进行固定染色、全尺寸、毫米度试样的刚性嵌入

For over a hundred years, the histological study of tissues has been the gold standard for medical diagnosis because histology allows all cell types in ...

Construction of a Multilayered Mesenchymal Stem Cell Sheet with a 3D Dynamic Culture System

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low cell retention and poor survival within the target zone. However, during the in vitro construction process, a solution for maintaining stem cell bioactivity and increasing the cell amount within the cell sheet is urgently needed. Here, this protocol presents a method for constructing a multilayered cell sheet with favorable stem cell bioactivity and optimal operability. Decellularized porcine pericardium (DPP) is prepared by phospholipase A2 (PLA2) decellularization method as the cell sheet scaffold, and rat bone marrow mesenchymal stem cells (BMSCs) are isolated and expanded as the seeded cells. The temporary multilayered cell sheet structure is constructed by using RAD16-I peptide hydrogel. Finally, the cell sheet is cultured with a dynamic perfusion system to stabilize the three-dimensional (3D) structure, and the cell sheet could be obtained following a 48-hour culture in vitro. This protocol provides an efficient and feasible method for constructing a multilayered stem cell sheet, and the cell sheet could be developed as a favorable stem cell therapy product in the future.

This article provides an efficient and feasible method for constructing multilayered stem cell sheets with favorable stem cell property.

3D 动态培养系统构建多层间充质干细胞片材

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low ...

A Human 3D Extracellular Matrix-Adipocyte Culture Model for Studying Matrix-Cell Metabolic Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of cellular function. The ECM plays a particularly important role in adipose tissue function in obesity, and alterations in adipose tissue ECM deposition and composition are associated with metabolic disease in mice and humans. Tractable in vitro models that permit dissection of the roles of the ECM and cells in contributing to global tissue phenotype are sparse. We describe a novel 3D in vitro model of human ECM-adipocyte culture that permits study of the specific roles of the ECM and adipocytes in regulating adipose tissue metabolic phenotype. Human adipose tissue is decellularized to isolate ECM, which is subsequently repopulated with preadipocytes that are then differentiated within the ECM into mature adipocytes. This method creates ECM-adipocyte constructs that are metabolically active and retain characteristics of the tissues and patients from which they are derived. We have used this system to demonstrate disease-specific ECM-adipocyte crosstalk in human adipose tissue. This culture model provides a tool for dissecting the roles of the ECM and adipocytes in contributing to global adipose tissue metabolic phenotype and permits study of the role of the ECM in regulating adipose tissue homeostasis.

We describe a 3D human extracellular matrix-adipocyte in vitro culture system that permits dissection of the roles of the matrix and adipocytes in contributing to adipose tissue metabolic phenotype.

用于研究基质细胞代谢串扰的人类3D细胞外基质-脂肪培养模型

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of ...