Mechanical Deformation of Superelastic NiTi Wire at Different Deflections in an Orthodontic Bracket System

@#Introduction: Most patients with malocclusion are given orthodontic leveling therapy with the aim of reducing the vertical discrepancy between teeth. This computational study aims to evaluate the degree of deformation of superelastic NiTi arch wire upon bending at different deflections in a bracket system. Methods: A three-dimensional finite-element model of a wire-bracket system was developed to simulate the bending behavior of superelastic NiTi arch wire in three-brackets configuration. A superelastic subroutine was integrated in the model to anticipate the superelastic behavior of the arch wire. The mid span of the arch wire was loaded to different extent of deflections, ranging from 1.0 to 4.0 mm. The mechanical deformation of the arch wires was accessed from three parameters, in specific the unloading force, the bending stress and the martensite fraction. Results: The superelastic wire deflected at 4.0 mm yielded smaller unloading force than the wire bent at 1.0 mm. The bending stress was highly localized at the wire curvature, with the stress magnitude increased from 465 MPa at 1.0 mm to 951 MPa at 4.0 mm deflection. The martensite volume consistently increased throughout the bending, with a fully transformed martensite was observed as early as 2.0 mm of deflection. The magnitude of bending stress and the volume of fully transformed martensite increased gradually in relation to the wire deflection. Conclusion: The wire-bracket system induced localize wire deformation, hindering complete utilization of superelasticity during orthodontic treatment.

Tratamiento de maloclusión de clase III con arco multiloop edgewise arch wire (meaw) reporte de caso clínico / Treatment malocclusion class III with multiloop edgewise arch wire (meaw) case report

Resumen En la actualidad hay diferentes formas de abordar la maloclusión de clase III, todas las formas tienen como objetivo principal solucionar la maloclusión y están encaminadas a diagnosticar y llevar al paciente a una oclusión es table, estética y sobretodo sin daño alguno a los tejidos que conforman el sistema estomatognático. Se muestra en este artículo el manejo de la ma loclusión de clase III con arcos de Multiloop Edgewise Arch Wire (MEAW) como una opción rápida, estable y de excelentes resultados para la solu ción de este tipo de discrepancias. La maloclusión de clase III puede ser tra tada de diferentes formas como el tratamiento temprano, la compensación dental, el camuflaje esquelético y la opción quirúrgica. La compensación dental puede ser de diferentes formas, como por ejemplo: exodoncias de premolares inferiores, torque inferior negativo y positivo superior, con ayuda de anclaje esquelético (mini tornillos) y muchas más que no se enuncian. En los casos que se involucra el perfil o la simetría facial y su origen es de características de ADF (Anomalía Dentocranéo Maxilofacial) requirieran de cirugía ortognatica para su solución, puesto que es de origen esquelético y debido a severidad es no compensable. Este articulo muestra un manejo diferente como opción de compensación de maloclusión de clase III. Es un reporte de caso clínico de un paciente del Posgrado de Ortodoncia de la Universidad Antonio Nariño de la clínica de arco recto manejado con brac kets de prescripción MBT Gemini Unitek 3M slot 0.022"x0.025" los cua les se les coloca arcos de Multiloop Edgewise Arch Wire (MEAW) después de ocho meses de tratamiento, cuatro meses en alineación y nivelación y cuatro meses del uso arcos de Multiloop Edgewise Arch Wire (MEAW) la corrección dentoalveolar se corrige gracias a la retracción canina y molar de 6mm bilateral haciendo rotar el plano de oclusión según la filosofía del tratamiento de Multiloop Edgewise Arch Wire (MEAW) obteniendo las seis llaves de la oclusión de Andrews.

Abstract At present, there are different ways of approaching Class III malocclusion, all of which have the main objective of solving malocclusion and are aimed at diagnosing and bringing the patient to a stable, aesthetic occlusion and above all without any damage to the tissues that make up the Stomatognatic system. This paper deals with the handling of Class III malocclusion with Multiloop Edgewise Arch Wire (MEAW) as a fast, stable and excellent choice for solving this type of discrepancy. Class III malocclusion can be treated in different ways such as early treatment, den tal compensation, skeletal camouflage and surgical option. The dental compensation can be of different forms, as for example: extractions of lower premolars, negative inferior torque and superior positive, with the aid of skeletal anchorage (TAD) and many more that are not stated. In cases, involving facial profile or symmetry and its origin is the characteristics of ADF (Maxillofacial Dentocranial Anomaly) require orthognathic surgery for its solution, since it is of skeletal origin and due to severity is not compensable. This article shows a different management as an option for class III malocclusion compensation. It is a clinical case report of a patient of the Orthodontics Postgraduate of the Antonio Nariño University of the straight arch clinic handled with MBT Gemini Unitek 3M slot 0.022 "x0.025" brackets which are placed with Multiloop Edgewise Arch arcs Wire (MEAW) after eight months of treatment, four months in alignment and leveling, and four months of use Multiloop Edgewise Arch Wire (MEAW) correction is corrected by bilateral canine and molar retraction by rotating the plane Of occlusion according to the philosophy of the treatment of Mul tiloop Edgewise Arch Wire (MEAW) obtaining the six keys of the Andrews occlusion.

An in vitro comparison of resistance to second and third order archwire activations of three different varieties of esthetic brackets.

Background: When ceramic brackets were introduced as an esthetic alternative to the stainless steel brackets, it was a step ahead in the use of esthetic appliances for orthodontic treatment. Although ceramic brackets had overcome the drawbacks of the initial polycarbonate brackets such as staining and bracket slot distortion, they posed an altogether different problem. This was on account of the physical properties of the ceramic material, namely brittleness. Purpose of the Study: The purpose of this study is to investigate the physical properties of three different varieties of esthetic brackets, i.e., “MXI” ceramic bracket, “Spirit MB” bracket (Ormco), a composite bracket with metal slot reinforcement and the third one fiber bracket, with silicious copolymer, Natura (Leone Co.). Aims and Objective of the Study: The objective of this study is to compare the torsional resistance of the brackets and resistance of brackets to second order archwire activations. Conclusion: The strength of the selected brackets was more than sufficient to withstand orthodontic load without any fracture or deformation.

Maxillary protraction and multiple loop edgewise arch wire technology in treatment of early mixed dentition skeletal class Ⅲ malocclusion / 中华医学美学美容杂志

Objective To evaluate the orthodontic effect of surgery on mixed dentition period class Ⅲ malocclusion and to investigate the effective therapeutic method of the skeletal class Ⅲ malocclusion.Methods A total of 20 patients aged 8.5 to 9.1 years with early mixed dentition class Ⅲ skeletal malocclusion.The treatment was divided into two phases.During the first phase,the entire stuffy group was treated with a bonded maxillary expansion and protraction.During the second phase,the entire study group received multiple loop edgewise arch wire (MEAW) treatment until an ideal occlusion relationship achieved.Comparison of the pre-and post-orthodontic treatment cephalometric radiographs had been done after maxillary protraction and MEAW were applied for patients.Results In the 20 patients after orthodontic treatment,Class Ⅲ skeletal facial profile was improved,the retraction of anterior teeth was obvious,and there were significant changes in dentition; the profile of soft tissue and satisfactory occlusion relationship were significantly improved,as compared with the changes between pre-treatment and post-treatment.Conclusions Skeletal Ⅲ malocclusion in early mixed dentition can be successfully treated.The results can be satisfied with improved class Ⅲ skeletal and molar relationship,high-angle and profile of soft tissue.

Treatment of skeletal crossbite young adults with mandibular deviation by RME and MEAW techniques / 中华医学美学美容杂志

Objective To evaluate the effects of multiloop edgewise arch wire(MEAW)technique combined with rapid maxillary expansion(RME)in correcting skeletal crossbite young adults with mandibular deviation.Methods 9 young adults with skeletal class Ⅲ malocclusion and mandibular deviation were selected(4 males,5 females,aged from 16.2-18.8 years).They were all corrected with RME and MEAW techniques.Cephalometric radiographs were taken and analyzed at the pretreatment(T1)and post-treatment(T2).Students't-test was used to determine if there were significant differences between the 2 time periods.Results SNA increased by(1.4+1.7)°,SNB decreased by(0.7+0.9)°,and ANB increased by(2.1+0.9)°;U1-SN increased by(2.7+3.7)°and L1-MP decreased by(5.4+2.9)°.MP-SN and Mp-FH increased by(1.9+2.0)°and(1.1+2.6)°respectively,neither of which had significant difference.Maz-Maz' increased by(2.6+2.8)mm,while Um-Um'increased by(6.2+5.9)mm.The latter had significant difference.△Cd-Me and △Cd-Go decreased by (3.7+2.1)mm and(2.8+1.6)mm respectively;while ManDP-MSL and Me-MSL decreased by (3.8+2.3)mmand(3.6+2.5)mm,respectively.All of them had significant differences.Conclusion MEAW technique combined with RME is a clinically effective method for correcting adults with mild and moderate skeletal crossbite and mandibular deviation.

Mandibular clinical arch forms in Koreans with normal occlusions / 대한치과교정학회지

The purpose of this study was to clarify morphologic characteristics between mandibular clinical arch forms in Koreans with normal occlusions. The study included data from 102 Koreans. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The dental arches were classified into ovoid, square and tapered forms. The frequency distributions of the three mandibular arch form classifications were determined and compared between male and female subjects. No significant differences in arch form size were found between the sexes. However, there were a few differences in molar width. It was useful to classify mandibular clinical arch forms present in normal occlusion samples into ovoid, square and tapered categories. The frequency of the ovoid form was the highest, and that of the square form was the second highest. The tapered arch form was found in less than 10 percent of subjects. No significant differences in their frequency distributions and dimensions were shown between males and females.

A finite element analytical model of multiloop edgewise arch wire / 解放军医学杂志

Objective To construct a finite element analytical model of multiloop edgewise arch wire(MEAW),and study its mechanical characteristics.Methods Three-dimensional(3D) model of dentition-bracket-arch wire was set up in an initial graphics exchange specification(IGES) format complex by Pro/E software.The multiloop edgewise arch wire was spliced on the lower dentition.After dividing the arch wire and brackets with quarter-tetrahedron element method,the model was analyzed by ANSYS(an engineering simulation software).Results The finite element analytical model of multiloop edgewise arch wire was successfully built up.Based on the model,when multiloop edgewise arch wire was subjected to a heavy strength in certain parts(such as tooth 3,4),the anti-force strength on the other brackets(such as tooth 1,2,5,6,7) was not so heavy.The subjected strength was light and soft,especially on the first molar.Conclusion The results suggest that the finite element analytical model of multiloop edgewise arch wire built up in the experiment may be used to study the integrated mechanical characteristics,reveal the orthodontic specialty,and discuss the orthodontic mechanisms of multiloop edgewise arch wire techniques.

An experimental study of the regional load deflection rate of multiloop edgewise arch wire / 实用口腔医学杂志

Objective:To compare the regional load deflection rate(LDR) of multiloop edgewise arch wire(MEAW) in the individual interbracket span,to understand the mechanical properties of MEAW.Methods:The stainless steel wire of 0.41 mm?0.64 mm was bent with single L-loop of 5 different sizes as described by Kim.The LDR of each L-loop at the individual interbracket span when loading and unloading was measured by using the Instron at a crosshead speed of 1 mm/min and maximum deflection of 1.0 mm at room temperature.Five specimens were tested under each experimental condition to eliminate the possibility of changes in the physical properties of the wires as a result of the stress from repeated measurements.The date were analysed by SPSS 11.0.Results:L-loops of MEAW had different LDRs regionally,except the regional LDRs between the canine and the first premolar and that between the first and second premolar were identical and moderate,a high value for the anterior segments and a low value for the posterior segments,the difference was statistically significant(P

A three-dimensional Finite element analysis for initial stress of maxillary incisors during activation of upper utility arch wire / 대한치과교정학회지

The purpose of this study was to find the difference of stress distribution of initial compressive and tensile stress when anterior section of uppor utility arch was activated crown lingual torque of 5degrees, 10degrees, 15degrees through three dimensional finitc element analysis. For this study, the finite element model of upper central and lateral incisors 1st, and 2nd, premolars and 1st. molars and each periodontal membrance and upper utility arch were made. From the solutions of ANSYS the followings were obtained.

A FEM analysis for initial stress on the upper canine by orthodontic force of intrusion arch wire activation / 대한치과교정학회지

The purpose of this study was to find the distribution and measurement of compressive and tensile stress when intrusi- on arch wire is forced engage with upper canine and to analysis stress at each section through FEM. And we compare compressive and tensile ratio at each section. The results were as follows. 1. At FA point and cemento-enamel junction of upper canine, compressive and tensile force ratio is about the same. 2. At apex, compressive force is the four times as tensile force. ; In intrusion, we show root resorption at apex. 3. At Cemento-enamel junction, the compressive and tensile force show the maximun value except FA point.

Effect of the depth and angle of the reverse-curve arch wires on the perpendicular force exerted to teeth / 实用口腔医学杂志

Objective:To analyze the perpendicular force on each tooth produced by the reverse-curve arch wires of various angles and depths using the method of 3-D finite element (3-D FEM) analysis. Methods:3-D FEM models of lower teeth, periodontal ligaments and alveolar bone as well as the 0.46 mm?0.64 mm inch stainless steel reverse-curve arch wires with different angles and depths were developed with the ANSYS finite element software, and the displacements of deformation of the reverse-curve arch wires were established on the models. Results:A ideal 3-D FEM was construct,including 2 709 elements and 1 969 nodes. The depth and angle of the reverse-curve arch wires produced obvious effect on the force exerted to teeth, and they could alter both the strength and the direction of the force. The force was mainly loaded on the canines, the second premolars and the molars, while less loaded on the incisors. Affected by the reverse-curve arch wires, the perpendicular force on the incisors were brought intrusively and on the molars were brought intrusively and distal upright; however, the canines and the bicuspids, in the perpendicular direction, moved along with the transformation of the angle and depth of the reverse-curve arch wires. When the angle of reverse-curve arch wires was fixed, the intrusive force on the incisors and molars was increased along with the increase of depth of the reverse-curve arch wires. Perpendicularly, the canines underwent a process from extrusion to intrusion, while the bicuspids were from intrusion to extrusion. When the depth of reverse-curve arch wires was fixed, the intrusive force on the incisors and molars was increased along with the increase of angle of the reverse-curve arch wires. The canines underwent a process from intrusion to extrusion.Conclusion:The variation of the angle and depth of the reverse-curve arch wires may produce evident effect on the force exerted to teeth.

Mechanical analysis on the shape-memory arch wire / 대한치과교정학회지

This study was designed to investigate the displacements and reaction forces of teeth caused by the application of the rectangular shape-memory arch wires with curve of Spee. Computer-aided three dimensional finite element method was adopted. This finite element model consists of brick element for teeth. beam element for the wire, and contact element for the periodontal ligament. And the applicaton of the MEAW(Multiloop Edgewise Arch Wire) was also studied so that the results of the two methods can be compared each other. Total number of the nodes and elements were found to be 5925 and 4031, repectively. In addition, several types of elastics and corresponding displacements and reaction forces were examined. The findings of this study were as follows: 1. When the rectangular shape-memory arch wire with curve of Spee was used alone, the intrusion and labioversion was noticeable on the upper incisors, while the upper molars showed less intrusion. With MEAW, the intrusion and labioversion of the upper incisors were slightly larger than those when the shape-memory arch wire was used, but on the upper molars the opposite result was obtained with respect to the intrusion. 2. The shape-memory arch wire with the vertical elastics caused the larger downward displacement on the upper canine than that when the MEAW was used with the vertical elastics. However, the downward displacement of the upper incisors was larger in MEAW. The uprighting and buccoversion of the molars were observed in both cases. 3. The use of the Class II or III elastics showed the extrusion and changes in torque of the corresponding teeth. The downward displacement of the upper canine was increased when the Class II and vertical elastics were applied simultaneously, but it was decreased when both of the Class III and vertical elastics were used.