• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.411-424
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• 1999

The purpose of this study was to find the difference of stress distribution of initial compressive and tensile stress when anterior section of upper utility arch was activated crown lingual torque of $5^{\circ},\;10^{\circ},\;15^{\circ}$ through three-dimensional finite 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 membrane and upper utility arch were made. From the solutions of ANSYS the followings were obtained. 1. $5^{\circ},\;10^{\circ},\;15^{\circ}$ crown lingual torque produce the almost similar distribution and measurement of initial compressive and tensile stress. 2. Acivated upper utility arch torqued central inciors lingually and lateral incisors labially.

• Journal of Yeungnam Medical Science
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• v.4 no.1
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• pp.151-156
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• 1987

A 25 year and 7 month old man patient who had Angle's classII division 2 malocclusion combined with anterior crowding of upper & lower part was treated by bioprogressive mechanism. After setting our objectives through the use of V.T.O., we programmed a sequence of mechanics. The possible objectives of treatment in the classII division 2 malocclusion can be listed as follows. 1) Relief of crowding & irregularities. 2) Relief of anterior gingival trauma & correction of interincisal inclination. 3) Correction of buccal segment relationship. We'd applied the classII intermaxillary elastics, Quad helix, utility arch wire and sectional arch wire in order to achieve anticipated objectives. As compared with pre & post treatment cephalogram, the result accomplished by this mechanics showed to us that interincisal angle was improved and favorable molar relationship was achieved.

• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.535-549
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• 1999

The Purposes of this study were to investigate the initial tissue changes on the teeth and surrounding tissues under contraction and intrusive force by contraction UTA. A control and experimental dogs, 10-months in age, were studied. Contraction and intrusive force(60gm) were applied at upper four incisors by contraction UTA. Experimental dogs were sacrificed at 2 weeks and 4 weeks after force application, respectively. In this study, 2 experimental groups were designed by the duration of force applied(E1, E2). The specimens were taken around the upper first and second incisor in each groups and were prepared for the H-E and MT stain for light microscopic observation. From the results of the study, the following conclusions may be drown. : 1. In control group, the periodontal ligament width was constant from apical third to cervical third of the root and periodontal fiber arrangement was horizontal or oblique in cervical third, oblique in middle third and apical third. In alveolar bond, smooth appearance was shown with osteoblast. 2. In experimental group 1, in proportion to force was concentrated at labial middle third and apical third of root of the upper first and second incisors, root of these tooth tipped labially and intruded at a time. 3. In experimental group 2, periodontal ligament width and arrangement was similar to control and observed strong calcified response at the labial middle third of root. But, alveolar bond resorption and cementum resorption were as before seen at labial middle third and apical third of root that force was concentrated.