• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.155-163
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• 1988

The purpose of this study was to evaluate and compare frictional forces generated between orthodontic brackets and arch wires. Independent variables were chosen for study: arch wire size and shape, arch wire material, bracket width, and second-order angulation between bracket and arch wire. Kinetic frictional forces of stainless steel (0.014', 0.016', 0.018', 0.016' ${\times}$ 0.022', 0.018' ${\times}$ 0.022'), $\beta-titanium$ (0.016' ${\times}}$ 0.022') arch wires were measured on wide and junior edgewise twin brackets (0.018' ${\times}$ 0.022' slot). Instron was used to pull arch wires while $0^{\circ},\;3^{\circ},\;6^{\circ},\;or\;9^{\circ}$ angulation between and wire and bracket was given. The results were as follows: 1. The frictional force of $\beta-titanium$ wire was larger than that of stainless steel wire. 2. The frictional force was generally increased as the size of wire is increased. 3. The frictional force of rectangular wire was larger than that of round wire. 4. As second order angulation was increased, the frictional force was also increased. 5. The frictional force was larger on a wide bracket than on a junior bracket.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.481-493
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• 1991

The purpose of this study was to obtain the norm of the crown shape (tip, torque, in/out) and arch form, and to provide basic data for fabricating straight wire bracket and ideal arch wire for Korean. 100 subjects aged from 17 to 26 (50 females, 50 males) were selected with a normal occlusion. By measuring the size, angulation, inclination, arch width, facial prominance of the teeth and the molar offset, the following results were obtained. 1. Average, standard deviation, minimum, maximum of each measuring item for each teeth were obtained. 2. Intermolar width (${\underline{6}}$ to ${\underline{6}}$) of upper arch before occlusal surface cutting and intermolar width of upper arch (${\underline{6}}$ to ${\underline{6}}$, ${\underline{7}}$ to ${\underline{7}}$) after occlusal surface cutting showed statistical difference. There was no difference between sexes in any other measuring items. 3. Arch form and specification of straight wire bracket for Korean who have normal occlusion was obtained.

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.735-758
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• 1994

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 application 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 Sun 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.

• The Journal of the Korean dental association
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• v.8 no.4
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• pp.361-362
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• 1970

LINGUAL ARCH APPLIANCE는 1908년 Mershon이 처음 창시한 교정장치로 band를 사용하는 교정장치중 가장 간단하면서도 여러가지 장점을 지니고 있다. 이 장치는 특히 성장발육기의 소아교정에 최적하여 치아의 기능을 제한하지 않으며 악골 및 치아의 자연적인 성장발육을 허용하고 자연적인 치아이동을 도모하게 한다. 또한 이 장치의 특징은 지속적인 교정치료보다는 간헐적인 치료를 한다는 사실이다.예를 들면 Angle씨 2 급부정교합 즉 상악전돌의 치료시는 상악에 Libial arch wire, 하악에 Lingual arch wire를 장착하고 여기에 악간고무를 이용하여 2급의 교합상태를 개선한후 수개월간 장치를 제거하여 치아의 자연적인 적응을 허용하고 다시 장치를 장착하여 치료를 계속하는 것이다.

• Archives of Craniofacial Surgery
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• v.15 no.2
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• pp.59-62
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• 2014

Background: The zygoma is the most prominent portion of the face. Almost all simple zygomatic arch fractures are treated in a closed fashion with a Dingman elevator. However, the open approach should be considered for unstable zygomatic arch fractures. The coronal approach for a zygomatic arch fracture has complications. In this study, we introduce our method to reduce a special type of unstable zygomatic fracture. Methods: We retrospectively reviewed zygomatic arch view and facial bone computed tomography scans of 424 patients who visited the Wonju Severance Christian Hospital from 2007 to 2010 with zygomaticomaxillary fractures, among whom 15 patients met the inclusion criteria. Results: We used a Dingman elevator and K-wire simultaneously to manage this type of zygomatic arch fracture. Simple medial rotation force usually collapses the posterior fractured segment, and the fracture becomes unstable. Thus, the posterior fracture segment must be concurrently elevated with a Dingman elevator through Keen's approach with rotation force applied through the K-wire. All fractures were reduced without any instability using this method. Conclusion: We were able to reduce unstable and difficult zygomatic arch fractures without an open incision or any external fixation device.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.31-51
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• 1991

This study was designed to survey the stress distributions and deflections which were derived from MEAW by the computer-aided three dimensional finite element analysis of teeth and surrounding bone composed of 2839 solid elements and 4621 nodes. MEAW model was also made using the 90 beam elements and the results were expressed by quantitative and visible ways. The findings of this study were as follows. 1 In case of vertical load on the MEAW there were extrusions of anterior teeth and upright effects of the posterior teeth. 2. Without applying the vertical elastics on the MEAW there were intrusions of anterior teeth, but relatively mild force was transmitted to the posterior teeth area. Torque forces were observed on the incisors and molars, and canine was intruded without torque. 3. The magnitudes of forces were different by the amounts of tip back bends of MEAW. 4. The displacements were in inverse proportion to the cross section areas of the wires according to the experiment using the 5 different size arch wires. 5. The difference of deflections between the MEAW and plain arch wire was not so big as the theoretical one but the deflections of MEAW were much more than the plain arch wire in every X, Y, Z direction.

• The korean journal of orthodontics
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• v.49 no.6
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• pp.349-359
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• 2019

Objective: The aim of this study was to analyze three-dimensional (3D) changes in maxillary dentition in Class II malocclusion treatment using arch wire with continuous tip-back bends or compensating curve, together with intermaxillary elastics by superimposing 3D virtual models. Methods: The subjects were 20 patients (2 men and 18 women; mean age 20 years 7 months ${\pm}$ 3 years 9 months) with Class II malocclusion treated using $0.016{\times}0.022-inch$ multiloop edgewise arch wire with continuous tip-back bends or titanium molybdenum alloy ideal arch wire with compensating curve, together with intermaxillary elastics. Linear and angular measurements were performed to investigate maxillary teeth displacement by superimposing pre- and post-treatment 3D virtual models using Rapidform 2006 and analyzing the results using paired t-tests. Results: There were posterior displacement of maxillary teeth (p < 0.01) with distal crown tipping of canine, second premolar and first molar (p < 0.05), expansion of maxillary arch (p < 0.05) with buccoversion of second premolar and first molar (p < 0.01), and distal-in rotation of first molar (p < 0.01). Reduced angular difference between anterior and posterior occlusal planes (p < 0.001), with extrusion of anterior teeth (p < 0.05) and intrusion of second premolar and first molar (p < 0.001) was observed. Conclusions: Class II treatment using an arch wire with continuous tip-back bends or a compensating curve, together with intermaxillary elastics, could retract and expand maxillary dentition, and reduce occlusal curvature. These results will help clinicians in understanding the mechanism of this Class II treatment.

• The korean journal of orthodontics
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• v.22 no.4 s.39
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• pp.823-836
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• 1992

Guiding a tooth along an arch wire results in a counteracting frictional force among arch wires, bracket and ligature. This frictional forces should be eliminated or minimized when orthodontic teeth movement is being planned. The purpose of this study was to evaluate the changes of width, cross-sectional forms and surface morphologies of stainless steel wire and $Elgiloy^{\circledR}$ wire after electropolising. Experimental variables included in this experiment were arch wire materials, current, electrolyte temperature and polishing time. Wire widths were measured by micrometer and cross-sectional forms and surface morphologies were examined with optical microscope and scanning electron microcope. The results were as follows: 1. The mean and standard deviation of widths of stainless steel wire and $Elgiloy^{\circledR}$ wire varying polishing time with condition of $249A/dm^2$ and $20^{\circ}C,\;249A/dm^2$ and, $332A/dm^2$ and $20^{\circ}C$ and $332A/dm^2$ and $250^{\circ}C$ were obtained. 2. With increasing polishing time, the widths of stainless steel wire and $Elgiloy^{\circledR}$ wire became decreased proportionally 3. The changes of widths of stainless steel wire and $Elgiloy^{\circledR}$ wire were statistically insignificant between $20^{\circ}C$ group and $25^{\circ}C$ group, but significant between $249A/dm^2$ group and $332A/dm^2$ group. 4 The cross-sectional forms of wire after electropolishing were not changed in stainless steel wire, and while it were changed to rounded corners in $Elgiloy^{\circledR}$ wire. 5. The surface morphologies of wire after electropolishing were scratch-absent and more smoothened both in stainless steel wire and $Elgiloy^{\circledR}$ wire.

• The Journal of the Korean dental association
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• v.13 no.9
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• pp.823-828
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• 1975

We have effectually treated 22 years girl who had complained of an aterior open-bite. Treatment was based on non-extracted and multibanded technigue at the use of horizontal loop with 0.016 inch green Elgiloy wire. Anteior cross elastics, C1Ⅲ intermaxillary elastics, occasicnally C1.Ⅱ elastics were used. when vertical discrepancy was corrected, we changed the arch wire making use of 0.018 ×0.022 inch rectangular wire with 1st. and 2nd. order bend. After 12mons. the ideal arch wire with tie back loop was placed for stabilizing arch. Nearly after 20 months bands were removed and placed retainer.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.391-398
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• 1998

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.