The authors would like to acknowledge all colleagues who made this work possible, especially Drs. Aditya Chhibber and Ravindra Nanda. The authors would like to thank the Biodynamics &#38; Bioengineering Lab at UCONN Health for the facilities provided during the development of this project.

1. Experimental Setup
<ol>
	<li>Mark the precise position for the placement of molar tubes and incisor brackets on the aluminum pegs of the OWT by using a customized &#39;jig&#39;.</li>
	<li>Bond standard self-ligating brackets with composite material. Light cure for 40 seconds.</li>
	<li>Insert a 0.021 x 0.025-inch stainless steel (SS) &#39;ovoid&#39; maxillary archwire into the bracket slots.</li>
	<li>Place the testing apparatus in the glass chamber.</li>
	<li>Check for any unintended archwire activation. Any activa...

<ol>
	<li>Burstone, C. J., Koenig, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force+systems+from+an+ideal+arch.">Force systems from an ideal arch.</a> Am J Orthod. 65 (3), 270-289 (1974).</li><li>Koenig, H. A., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force+systems+from+an+ideal+arch:+Large+deflection+considerations.">Force systems from an ideal arch: Large deflection considerations.</a> Angle Orthod. 59 (1), 11-16 (1989).</li><li>Burstone, C. J., Koenig, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Creative+wire+bending:+The+force+system+from+step+and+V+bends.">Creative wire bending: The force system from step and V bends.</a> Am J Orthod and Dentofac Orthop. 93 (1), 59-67 (1988).</li><li>Ronay, F., Kleinert, W., Melsen, B., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force+system+developed+by+V+bends+in+an+elastic+orthodontic+wire.">Force system developed by V bends in an elastic orthodontic wire.</a> Am J Orthod and Dentofac Orthop. 96 (4), 295-301 (1989).</li><li>Demange, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Equilibrium+situations+in+bend+force+systems.">Equilibrium situations in bend force systems.</a> Am J Orthod and Dentofac Orthop. 98 (4), 333-339 (1990).</li><li>Isaacson, R. J., Lindauer, S. J., Conley, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responses+of+3-dimensional+arch+wires+to+vertical+V+bends:+Comparisons+with+existing+2-dimensional+data+in+the+lateral+view.">Responses of 3-dimensional arch wires to vertical V bends: Comparisons with existing 2-dimensional data in the lateral view.</a> Semin Orthod. 1 (1), 57-63 (1995).</li><li>Upadhyay, M., Shah, R., Peterson, D., Takafumi, A., Yadav, S., Agarwal, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force+system+generated+by+elastic+archwires+with+vertical+V+bends:+A+three-dimensional+analysis.">Force system generated by elastic archwires with vertical V bends: A three-dimensional analysis.</a> Eur J Orthod. 39 (2), 202-208 (2017).</li><li>Gurgel, J. A., Kerr, S., Powers, J. M., LeCrone, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force-deflection+properties+of+superelastic+nickel-titanium+archwires.">Force-deflection properties of superelastic nickel-titanium archwires.</a> Am J Orthod Dentofacial Orthop. 120 (4), 378-382 (2001).</li><li>Gurgel, J. A., Kerr, S., Powers, J. M., Pinzan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Torsional+properties+of+commercial+nickel-titanium+wires+during+activation+and+deactivation.">Torsional properties of commercial nickel-titanium wires during activation and deactivation.</a> Am J Orthod Dentofacial Orthop. 120 (1), 76-79 (2001).</li><li>Hazel, R. J., Rohan, G. J., West, V. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force+relaxation+in+orthodontic+arch+wires.">Force relaxation in orthodontic arch wires.</a> Am J Orthod. 86 (5), 396-402 (1984).</li><li>Lundgren, D., Owman-Moll, P., Kurol, J., Martensson, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+orthodontic+force+and+tooth+movement+measurements.">Accuracy of orthodontic force and tooth movement measurements.</a> Br J Orthod. 23 (3), 241-248 (1996).</li><li>Goldberg, A. J., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+evaluation+of+beta+titanium+alloys+for+use+in+orthodontic+appliances.">An evaluation of beta titanium alloys for use in orthodontic appliances.</a> J Dent Res. 58 (2), 593-600 (1979).</li><li>Kusy, R. P., Whitley, J. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+and+mechanical+characteristics+of+stainless+steel,+titanium-molybdenum,+and+nickel+titanium+archwires.">Thermal and mechanical characteristics of stainless steel, titanium-molybdenum, and nickel titanium archwires.</a> Am J Orthod Dentofacial Orthop. 131 (2), 229-237 (2007).</li><li>Kapila, S., Sachdeva, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+properties+and+clinical+applications+of+orthodontic+wires.">Mechanical properties and clinical applications of orthodontic wires.</a> Am J Orthod Dentofacial Orthop. 96 (2), 100-109 (1989).</li><li>Verstrynge, A., Humbeeck, J. V., Willems, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-vitro+evaluation+of+the+material+characteristics+of+stainless+steel+and+beta-titanium+orthodontic+wires.">In-vitro evaluation of the material characteristics of stainless steel and beta-titanium orthodontic wires.</a> Am J Orthod Dentofacial Orthop. 130 (4), 460-470 (2006).</li><li>Tominaga, J. Y., Tanaka, M., Koga, Y., Gonzales, C., Kobayashi, M., Yoshida, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimal+loading+conditions+for+controlled+movement+of+anterior+teeth+in+sliding+mechanics.">Optimal loading conditions for controlled movement of anterior teeth in sliding mechanics.</a> Angle. 79 (6), 1102-1107 (2009).</li><li>Cattaneo, P. M., Dalstra, M., Melsen, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+finite+element+method:+A+tool+to+study+orthodontic+tooth+movement.">The finite element method: A tool to study orthodontic tooth movement.</a> J Dent Res. 84 (5), 428-433 (2005).</li><li>Fotos, P. G., Spyrakos, C. C., Bernard, D. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orthodontic+forces+generated+by+a+simulated+archwire+appliance+evaluated+by+the+finite+element+method.">Orthodontic forces generated by a simulated archwire appliance evaluated by the finite element method.</a> Angle Orthod. 60 (4), 277-282 (1990).</li><li>Geramy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alveolar+bone+resorption+and+the+center+of+resistance+modification+(3-D+analysis+by+means+of+the+finite+element+method.">Alveolar bone resorption and the center of resistance modification (3-D analysis by means of the finite element method.</a> Am J Orthod Dentofacial Orthop. 117 (4), 399-405 (2000).</li></ol>

The authors have nothing to disclose.

Orthodontic archwires have been studied in various ways8,9,10,11. They have also been evaluated for various mechanical properties, but they have seldom been analyzed for determining the force system they are going to create12,13,14,15. Three-point bending tests are po...

An important aspect of clinical orthodontic treatment is the knowledge of the force system produced by multibracket appliances. A clear understanding of the underlying biomechanical principles can help deliver predictable results and minimize potential side effects1. Recent years have seen a trend away from placing bends in archwires by building more activation with bracket position and design; however, comprehensive orthodontic treatment still requires placement of bends in archwires. Bends, when placed in different types and sizes of archwires, can create a wide variety of force systems suitable for different types of tooth movement. Although the force systems can become quite complex when multiple teeth are considered, a helpful starting point can involve a simple two-bracket system.
To date, V-bend mechanics have primarily been analyzed in the second order only, utilizing mathematical models1,2,3,4,5 and/or computer-based analysis/simulations6. This has yielded a basic understanding of the force system involved in the second order interaction of the arch wires with adjacent brackets (Figure 1). However, these methods impose certain boundary conditions in order to run&#160;simulations that might not hold true in actual clinical situations and deviations might occur. Recently, a new in vitro model involving force transducers was proposed for measuring three dimensional (3D) forces and moments created by evaluating not only second order archwire-bracket interactions but also in the third order7. However, the effect of different types of archwires on the force system at various bend positions along the incisor molar archwire span was not evaluated. Also, the study only involved evaluation of elastic orthodontic archwires, which are not the primary archwires on which tooth movement occurs. Therefore, the aim of this study was to evaluate the force system created by the placement of a V-bend at different locations in rectangular stainless steel and beta-titanium archwires in a 3D set up involving the molar and incisor brackets. Clinicians need to know the force system applied on the dentition when a specific combination of archwire bracket combination is used to fix a malocclusion.
The described technique has been developed to study the orthodontic force system in all the three planes of space, mimicking clinical reality. It is to be understood that it is extremely difficult to measure the force system clinically; therefore, such measurements have to be carried out&#160;in vitro. It is assumed that the force system created by a V-bend in the laboratory would be similar if replicated in the patient&#39;s mouth. A workflow was created to evaluate how the experimental set up has to be configured (Figure 2).
The orthodontic wire tester (OWT) is an innovative product developed by Division of Orthodontics in collaboration with the Bioengineering &#38; Biodynamics Laboratory, UConn Health, Farmington, CT, USA (Figure 3). It is designed to accurately mimic the arrangement of the maxillary teeth within the mouth and some intra-oral conditions while providing measurements of the force system created in all the three planes of space. The major mechanical components of the OWT are a Data acquisition device (DAQ), nano Force/Torque Sensors, humidity sensors, temperature sensors, and a personal computer. The testing apparatus is placed in a glass enclosure having temperature/humidity controls. This allows for partial simulation of the intraoral environment. The DAQ serves as the interface for the three sensors:&#160;humidity sensor, force/moment sensor,&#160;thermistor&#160;and the testing apparatus with the sensors situated on a platform&#160;(Figure 3). These are linked to a software program. The software is a platform and a development environment for visual programming and is used to control different types of hardware. It was chosen to automate the orthodontic wire tester.
A series of aluminum pegs are arranged on the testing apparatus to represent the teeth of the maxillary dental arch. Two of the pegs representing the right central incisor and right first molar are connected to sensors/load cells (S1 and S2). A load cell is a mechanical device that can measure the forces and moments applied to it in all the three planes (x-y-z): Fx, Fy, and Fz; and Mx, My, and Mz. The pegs are systematically positioned to create a dental arch form. Each peg is separated from the other by a precisely recorded measurement that is calculated using average tooth widths as observed in patients undergoing orthodontic treatment. The shape chosen for the experiment is an &#39;ovoid&#39; arch form created from a standardized template.

<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

A proper understanding of the force system created by various orthodontic appliances can make treatment of patients efficient and predictable. Reducing the complicated multi-bracket appliances to a simple two-bracket system for the purpose of force system evaluation will be the first step in this direction. However, much of the orthodontic biomechanics in this regard is confined to 2D experimental studies, computer modeling/analysis or theoretical extrapolation of existing models. The objective of this protocol is to design, construct and validate an in vitro 3D model capable of measuring the forces and moments generated by an archwire with a V-bend placed between two brackets. Additional objectives are to compare the force system generated by different types of archwires among themselves and to previous models. For this purpose, a 2 x 4 appliance representing a molar and an incisor has been simulated. An orthodontic wire tester (OWT) is constructed consisting of two multi-axis force transducers or load cells (nanosensors) to which the orthodontic brackets are attached. The load cells are capable of measuring the force system in all the three planes of space. Two types of archwires, stainless-steel and beta-titanium of three different sizes (0.016 x 0.022 inch, 0.017 x 0.025 inch and 0.019 x 0.025 inch), are tested. Each wire receives a single vertical V-bend systematically placed at a specific position with a predefined angle. Similar V-bends are replicated on different archwires at 11 different locations between the molar and incisor attachments. This is the first time an attempt has been made in vitro to simulate an orthodontic appliance utilizing V-bends on different archwires.

The total force and total moment experienced by each sensor at the center of the sensor plate are represented by their three orthogonal components: Fx, Fy, and Fz representing the forces along the x-axis, y-axis, and z-axis, respectively; and Mx, My, and Mz representing the moments around the same axes. The initial measurements at the sensors are converted mathematically to the force and moment values experienced by the bra...

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

The method presented here is designed to construct and validate an in vitro 3D model capable of measuring the force system generated by different archwires with V-bends placed between two brackets. Additional objectives are to compare this force system with different types of archwires and to previous models.

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

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

The apparatus described reduces a normal clinical set of 12 brackets to only two. Now this greatly simplifies our understanding of how an appliance works. It also provides a blueprint for testing and making modifications on similar appliances.This experiment answers some key questions related to the variation and force system created by V-bends. When placing those bands at different locations along the incisor molar arch span. The implications of this major apparatus is tend toward creating orthodontic appliances with a more predictable force system, which, at a clinical level would imply more predictable outcomes.To begin this procedure, insert a 0.021 by 0.025 inch SS ovoid maxillary archwire into the bracket slots. Then, place the testing apparatus in the glass chamber. Check for any unintended archwire activation.Any activation of the archwire will automatically create a force system, which will be displayed on the computer screen. If any archwire activation is observed, reposition the brackets, and check again. To fabricate a template archwire, place an archwire in the testing apparatus.Then, use a permanent marker to indicate the midline, a point immediately distal to the incisor bracket, and a point immediately mesial to the molar tube. Do the same for the contralateral side of the archwire. Next, transfer the archwire with the marked points to graph paper.Make a precise replica of the archwire on it, which can be used to determine the position of the V-bend for all archwires of the sample. Then, calculate the perimeter of the archwire segment L from I to M.Now, mark 11 points from I to M.Each point is a future V-bend position. Label each point from a0 to a10.Make sure that each bend position is separated from the other by an equal amount. Obtain a unique number for each bend position by calculating the a/L for each position. To place the V-bends, take a new archwire from the sample and place it on the template graph paper.Then, transfer one of the 11 bend positions bilaterally to the archwire. Use a rectangular archwire plier, or a light wire plier, to make symmetrical V-bends at both sides. Place the archwire on a flat platform and check the angle made by the two ends of the archwire with a protractor.Adjust the ends if necessary, so that an angle of 150 degrees is created. Subsequently, repeat the procedures for all archwires of the sample. To measure the force system, open the software program for data recording.Create a new folder for the data to be saved. Then, click Run to start the software. The program will display each of the three forces and three moment values at each sensor in real time.Wait for approximately 10 to 15 seconds for the fluctuations in data recording software to stop. Ensure that the graph lines for all the components of the force system show a flat line. Note that all six measurements at each sensor will show negligible values.Gently remove the testing apparatus from the platform. Use a Weingart plier to insert an archwire into the molar tubes. Next, open the door of the incisor bracket with a periodontal scaler.Lift the anterior portion of the archwire and insert it into the bracket slots. Make sure that the midline of the archwire coincides with the midline of the testing apparatus. After placing the archwire in the bracket slots, if the archwire has to be taken off for some adjustments, then the same archwire cannot be used and a new archwire will have to be inserted.Afterward, return the testing apparatus to the platform and close the door of the glass chamber. Set the temperature at thirty-seven degrees Celsius, and wait one minute for the temperature of the glass chamber to adjust. Click the Start Saving button on the software and allow the software to save and transfer data for at least 10 seconds.Click the Start Saving button again to end data transfer, then click STOP. Note that each measurement cycle generates 100 readings over the 10-second period for each component. Repeat the procedures for the 10 archwires of that specific bend position, and for all bend positions and types of archwires.To evaluate the error, open the software program for data recording. Create a new folder for the data to be saved. Then, click Run to start the software.The program will display each of the three forces, and three moment values at each sensor, in real time. Wait for approximately 10-15 seconds for the fluctuations in data recording software to stop. Ensure that the graph lines on the software for all the components of the force system show a flat line.Remove the testing apparatus from the platform. Using a light wire plier, bend one end of a straight length of a 0.021 x 0.025 in SS wire into a small hook. Insert the free end of the archwire into the molar tube from the distal side.Next, place the testing apparatus back on the platform. Attach a known weight to the hook and let it hang freely in the vertical plane by removing any type of interference. Close the door of the glass chamber.Click the Start Saving button on the software and allow the software to save and transfer data for at least 10 seconds. Click the Start Saving button again to end data transfer, then click STOP. Go to the document containing the saved data, export the data set to a custom designed data analysis spreadsheet, and repeat the error evaluation procedures for the incisor bracket.The vertical forces show symmetric and linear pattern for each of the six wire types. As the V-bend gets closer to either bracket, the vertical forces get higher. As the bend is moved farther beyond this point, the vertical force progressively increases.However, the directions of the individual vertical forces are reversed. Stainless steel archwires create a significantly greater force system than beta titanium archwires. Surprisingly, the relative force system created at the two brackets by the archwires, both in terms of size and type of archwire, is quite similar.In contrast, the moments show a nonlinear and asymmetric pattern. The flattening of Mxi, when V-bends are placed close to the molar tube, as well as the reversal of the moment direction in the molar tube from ax/L of 0.0 to 0.2 was similar for all archwires, and perhaps, represents a more fundamental nature of archwire bracket interaction and bracket orientation. The ratio of the moment of the two brackets shows some specific patterns observed across all archwires tested, and can be grouped into three distinct patterns.This approach can be utilized in numerous other clinical scenarios besides just V-bends. We have already begun testing some of those, and in the near future, we are looking at integrating this data directly with FEM simulations for similar setups. This approach will help in understanding and predicting clinical outcomes in patients.This will be a huge step in customizing treatment according to patient needs.

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10.4K 次观看.  University of Connecticut Health. The apparatus described reduces a normal clinical set of 12 brackets to only two. Now this greatly simplifies our understanding of how an appliance works. It also provides a blueprint for testing and making modifications on similar appliances.This experiment answers some key questions related to the variation and force system created by V-bends. When placing those bands at different locations along the incisor molar arch span. The implications of this major apparatus is tend toward cre...