• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.73-85
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• 1995

Multi-Vertical Loop Arch Wire(MVLAW) is a kind of appliance for uprighting the mesially inclined posterior teeth axes simultaneously. In this study MVLAW was classified as 3 types by modifing the vertical loop design and named type A, B and C. Each MVLAW was fabricated from .017'x.025' TMA wire and preactivated at the distal end of the open vertical loop with 10 degree tip-back bend(type B has an electric welding stop at the distal end of each loop and type C has no electric welding stop). Type A MVLAW was preactivated at the apex of each open vertical loop with 10 degree tip-back bend(the electric welding stop of type A is positionod at the mesial side of each loop). The aim of the present study was to identify when and which MVLAW is more effective to correct the buccal segment axes simultaneously. The Photoelastic overview of the upper and lower right quadrant showed that stress concentrations were observed in its photoelastic model. The obtained results were as follows : 1. Higher level compression can be seen clearly at the distal curvature of the lower 1st and 2nd molar when A type MVLAW was applied without short class m elastic, but mild compression cannot be seen at the distal curvature of lower anterior teeth using the class m elastic. 2. Higher concentration was presented at the mesial curvature from the lower 1st premolar to the 2nd molar than the anterior teeth when B type MVLAW without short class III elastic was applied, but using the short class III elastic, higher concentration of compression was presented in the anterior teeth area. 3. Areas of higher compression and tension were not observed at the mesial and distal curvature of the entire 1ower teeth except lower central and lateral incisors in C type MVLAW without short class III elastic, but using the short class III elastic, higher concentration was seen at the mesial curvature of the lower 1st premolar and 1ower anterior teeth.

• The korean journal of orthodontics
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• v.31 no.6 s.89
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• pp.559-566
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• 2001

This study was undertaken to demonstrate the forces in the mandibular alveolar bone generated by activation of the mandibular posterior crossbite appliance in the treatment of buccal crossbite caused by lingual eruption of mandibular second molar. A three-dimensional photoelastic model was fabricated using a photoelastic material (PL-3) to simulate alveolar bone. We observed the model from the anterior to the posterior view in a circular polariscope and recorded photogtaphically before and after activation of the mandibular posterior crossbite appliance. The following results were obtained : 1. When the traction force was applied on the buccal surface of the mandibular second molar, stress was concentrated at the lingual alveolar crest and root apex area. The axis of rotation also was at the middle third of the buccal toot surface and the root apex, so that uncontrolled tipping and a buccal traction force for the mandibular second molar were developed. 2. When the traction force was applied on the lingual surface of the mandibular second molar more stress was observed as opposed to those situations in which the force application was on the buccal surface. In addition, stress intensity was increased below the loot areas and the axis of rotation of the mandibular second molar was lost. In result, controlled tipping and intrusive tooth movements were developed. 3. When the traction forte was applied on either buccal or lingual surface of the second molar, the color patterns of the anchorage unit were similar to the initial color pattern of that before the force application. So we can use the lingual arch for effective anchorage in correcting the posterior buccal crossbite. As in above mentioned results, we must avoid the rotation and uncontrolled tipping, creating occlusal interference of the malpositioned mandibular second molar when correcting posterior buccal crossbite. For this purpose, we recommend the lingual traction force on the second molar as opposed to the buccal traction.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.111-126
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• 1998

In this study, radiographic evaluation was made using panoramic radiography and cross-sectional tomography of SCANORA/sup (R)/ in male and female adults in their 20's on the relationship between the maxillary sinus floor and the apex of the maxillary molar, to test the accuracy and effectiveness of the cross-sectional tomography, and to use this information in the assessment of preop. and postop. root canal treatment, apical surgery, extraction and implantology. Forty-one adults with an average age of 24.4 years were studied using panoramic radiography and cross-sectional tomography. In panoramic view and cross-sectional view, the position of the apices of maxillary molars were classified as separated, contacted, or protruded type; the general shape of the maxillary sinus floor was evaluated horizontally and vertically from cross-sectional tomography. The accuracy of each radiography was tested using maxilla from 5 fresh cadavers from the Anatomy Lab at Yonsei University Dental College, and panoramic view and cross-sectional tomography were taken in the same condition as with the patients. The results were as follows: 1. Panoramic view and cross-sectional view were taken in the maxilla specimen, and the actual distance between the maxillary sinus floor and the tooth apices were measured in the specimen; the median values of the distance from the tooth apices to the maxillary sinus floor in the panoramic view, cross-sectional view and in the actual maxilla specimen were 2.83 mm, 4.51mm, and 4.l5mm, respectively. In the cross-sectional view, the measured distance was close to the actual distance but in the panoramic view, the measured distance was far from the actual distance. 2. When the results of the panoramic view and cross-sectional view were compared, 40.5％ of the results agreed with each other in the two radiographic methods and buccal roots of the 2nd molar were the closest to the maxillary sinus floor in the cross-sectional tomography. 3. In cross-sectional view, when the vertical relationship of the maxillary sinus floor and maxillary roots was assessed, in 1st molars, type II (the sinus floor that extends down to the buccolingual furcation area) was predominant, while in 2nd molars, type I (the sinus floor located above the level connecting the buccal and lingual apices) was predominant. In the horizontal relationship, in 1st molars, type II (the lowest floor of the maxillary sinus located in between the buccal and lingual roots) was predominant; in 2nd molars, type I (the lowest floor of the maxillary sinus located on the buccal side of the buccal roots) and type II appeared in similar frequency. In conclusion, the SCANORA/sup (R)/ cross-sectional tomography was more effective than the frequently used panoramic view, in that the relationship of the maxillary molars and maxillary sinus floor can be evaluated more accurately and the buccolingual cross-sectional view can also be observed. And maxillary sinus floor that was close to maxillary 2nd molar had tendency to be located on buccal side than that close to 1st molar. Therefore, cross-sectional tomography is an effective and accurate method to evaluate the position of the teeth in relation to the sinus floor preoperative and can be easily used to diagnose localized periapical lesions. Also, the image quality obtained was quite satisfactory.

• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.1-16
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• 1988

The anatomical structure of pelvic limb, of thirty-one adult Korean native goats (Body weight: 14~17kg) was observed after skeletal preparation, and the osteometry was performed in each bone. The results were as follows: 1. The pelvic limb of the Korean native goat was composed of the hip bone, femur, patella, tibia, fibula, tarsal bones, metatarsal bone, phalanges and sesamoid bones. 2. The hip bone consisted of the ilium, ischium and pubis which fused each other, The gluteal surface of the ilium was directed dorsolaterally. The tuber sacrale and tuber coxae were formed at the dorsal apex and ventrolateral part of the iliac wing, respectively. The lesser ischiatic notch was deeper than the greater one. The ischiatic tubercles were triangular form and consisted of the dorsal, lateral and caudal ischiatic tubercles. The left and right hip bone indexes were 67.08, 66.20, the acetabular indexes were 93.78 and 92.10 and the obturator foramen. indexes were 53.84 and 54.77, respectively. 3. In femur, both of the greater and lesser trochanter were well developed but the third trochanter was not observed. The left and right femur indexes were 26.55 and 26.14, head indexes were 81.66 and 81.49 and the trochlear-epicondyle indexes were 42.47 and 41.63, respectively. 4. The patella was observed as an isosceles triangle with base lying proximal and the cranial surface was more convex. 5. The tibial shaft was sigmoid form and the popliteal notch was deep. There was a large nutrient foramen at the cranial aspect of the cranial intercondylar area. The tibial indexes were 22.09 in left and 21.10 in right. 6. The proximal extremity of the fibula was fused with the lateral condyle of the tibia but the distal one was observed independently as the malleolar bone. 7. The tarsal bones were five in number; the talus, calcaneus, centroquartal tarsal bone, first tarsal bone, and second-third tarsal bone. 8. The metatarsal bone was composed of a large metatarsal bone. resulted from the fusion of the third and fourth metatarsal bones, The structure of metatarsal bone was similar to the metacarpal bone but longer about 7mm. 9. The phalanges and sesamoid bones were similar to these of the thoratic limb. 10. The ratios of the lengths among the hip bone, femur, tibia and metafarsal bone were 1.71 : 1.54 : 1.73 : 1.00 in left and 1.68 : 1.53 : 1.72 : 1.00 in right, respectively.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.199-207
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• 2001

The segmented TMA T-loop spring, used for reciprocal space closure and described by Burstone, was used to achievebodily movement of canine. Photoelastic analysis is a technique for the transformation of internal stress into visible light patterns. The two-dimensional photoelastic stress analysis was performed, and stress distribution was recorded by photography. The purpose of this study was to visualize photoelastically the distribution of forces transmitted to the alveolus and surrounding structures using new segmented TMA T-loop spring for canine retraction. The results were as follows: 1. Decreased activation produced decreased stress of upper 1st. premolar extraction site and increased intrusive stress of upper 1st. molar, regardless of T-loop position. 2. At 5mm activation, More posterior positioning of T-loop Produced an increased stress in upper 1st. premolar extraction site. 3. At 3mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site and mesial lower half of upper 1st. molar mesio-buccal root. 4. At 1mm activation, More anterior positioning of T-loop produced an increased stress in upper mesial and blew apex area of upper canine root. 5. 0.25 B/L ratio and 3mm activation produced bodily movement of canine. To summarize, desired tooth movement and anchorage requirement is possible by altering the activation and mesio-distal position of the T-loop spring.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.401-409
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• 1997

The purpose of this study was to analize the initial stress distribution around apex and the alveolar bone of the upper anterior teeth when applying intrusive force by the use of utility arthwire, Burstono 3-piece infusion archwire, and 'J' hook headgear which is usually used in clinital practice. By the use of the polarization plate, initial stresses were analized when 80g and 150g forte applied. The results were as follows. 1. With the utility archwire, moderate levels of stress were evenly distributed on the apical areas of the anterior teeth and concentrated on the apical areas of the first molars. 2. With the Burstone's 3-piece intrusion archwire, moderate levels of stress were evenly distributed on the apical areas of the anterior and posterior teeth. 3. With the 'J' hook headgear, severe levels oi stress were widely distributed on the alveolar bone and apical areas of the upper anterior teeth, and concentrated on the apical area between the central and the lateral incisors. Especially, weak levels of stress appeared along the periodontal ligament space of all teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.275-280
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• 2009

Radicular cyst is a true epithelium lined cyst formed when epithelium at the apex of a nonvital tooth is stimulated by inflammation. It is the most common type of cyst in the oral cavity, but its frequency is low in the primary dentition. Treatment of large-sized cyst aims at conservation of adjacent structure and allowance of proper eruption of the successive permanent teeth in the primary dentition. Considering these two aspects, marsupialization or enucleation following decompression is recommended as a treatment means for large-sized radicular cyst. In this case, 8-year old boy visited the pediatric dentistry department. Yonsei University Dental Hospital, with the chief complaint of pain on the lower right area. Clinical and radiographic examinations revealed periapical radiolucent lesion on #84, which had previous pulp treatment and restorated with the stainless steel crown. Dislocation of its successive tooth, #44, was also observed. #84 was extracted and sent for biopsy. Through histologic examination, it was diagnosed as radicular cyst. Following its extraction, removable space maintainer was delivered, which was also used as a decompressor. During periodic check-up for next 22 months, favorable healing of the lesion and eruption of the successive tooth were observed.

• Applied Microscopy
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• v.39 no.2
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• pp.149-156
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• 2009

Fine structure of the dry adhesion system in the tarsal appendages of the jumping spider Plexippus setipes (Araneae: Salticidae) with examined using field emission scanning electron microscope (FESEM). The jumping spiders have the distinctive attachment apparatus for adhesion on smooth dry surface without sticky fluids. They attach to rough substrates using tarsal claws, however attachment on smooth surfaces is achieved by means of a tuft-like hair called a scopula. All eight legs have the scopulae with a pair of claws on the tip of feet, and each scopula is composed of two groups of setae that are capable of dry adhesion on smooth surface. The apex of each seta is flattened pad bearing many specialized adhesive setules on one side. The cuticular sensillae are interspersed at the dorsal surface of the seta. It has been revealed by this research that the contact area of the setule is always a triangular shape, and these cuticular surfaces are connected by the elongated stalks from the underlying setae. Moreover, adhesion between the numerous setules and the setae was prevented by the microscopic hairs, since these were interspersed on the upper side of the setae.

• Women's Health Nursing
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• v.8 no.4
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• pp.608-618
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• 2002

The purpose of this study is to analyze the type of ego states and stress coping style on female college students who are in the course of nursing study. This study is performed in the view of Transactional Analysis and designed to scrutinize descriptive correlations between the type of ego states and stress coping style. The subject is consists of 144 freshmen and sophomore, 138 junior and senior students group, who are students of K nursing college located in Seoul. The sampling investigation period is on Sept. 14, 2002 to Oct. 26, 2002. The measuring instrument used for Transactional Analysis ego state is 50 items Ego-gram research paper devised by Dusay(1997). For studying coping style, Folkman & Lazarus's measurement(1984) was adopted, which is translated and modified by Han, and Oh,(1990). Statistic average and standard deviation were generated by using SPSS PC+, t-test and Pearson correlation. The results were as follows: 1) In the type of ego states on both groups(lower group : freshmen, sophomore upper group : junior, senior) indicated the arithmetic apex NP(maximum value), then the point A was high and the data made a down slope to point AC. In the comparison to type of ego states between two groups, only at point CP, the data value of upper year students represented higher than that of lower year ones by C(t=2.28, p=.023). In the psychological energy level of ego states, both groups indicated average level.2) Stress coping style of whole students were highly and affirmatively dedicated to research. Consecutive consequences follow like this(high to low) : the central point of problem, search for social support, hopeful aspect and indifference. Especially hopeful aspect(t=.67, p=.05), relaxation of tension(t=-2.16, p=.03) made significant difference each other in the view of arithmetic calculation 3) While verifying coping style in terms of ego states level between lower and upper students group, In type CP, high level ego states group indicated significant difference on stress coping style area than low leveled group and made such sequences as the central point of problem, hopeful aspect, search for social support, positive interest and relaxation of tension. In type NP, sequences such as the central point of problem, search for social support, positive interest and relaxation of tension were emerged with little differences. In type A, the central point of problem, positive interest and relaxation of tension. In type FC, hopeful aspect, search for social support, positive interest and relaxation of tension. In type AC, hopeful aspect and indifference were derived significantly different(p<.05). 4) In the aspect of relation between ego states and coping style, type CP presented the central point of problem and relaxation of tension, type NP presented positive interest, search for social support and the central point of problem, type A showed the central point of problem, positive interest and relaxation of tension, type FC showed relaxation of tension, positive interest, search for social support, indifference and the central point of problem, type AC showed hopeful aspect, indifference and the central point of problem. All the sequence shown above had high-to-low procedure and represented static relations each other(p<.05).

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.419-429
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• 1998

This study was carried out in order to study early histologic changes and repair reaction appling to extrusive force for 3rd premolar of adult dogs. After 1 week of extrusive force with elastic chain, one of dogs was sacrified and after 3 weeks retention period, another dog was sacrified. The paraffin sections of samples were stained with Hematoxylin - Eosin and Masson's Trichrome and were examed by light microscopy . The obtained results as follows 1. In Hematoxylin - Eosin and Masson Trichrome stain of 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, oblique in apical third of root. in alveolar bone, smooth appearance was shown 2. In Group 1, all periodontal fiber arrangement was oblique toward tooth, and the periodontal ligament width increased Partially PDL was ruptured in apex. In MT stain, immature bone formation was seen at alveolar crest area. Active bone formation was observed along the one side of alveolus, and apical portion of pulp was involved with blood vessel rupture , vacuolization of pulp tissue and hyperemia 3. In Group 2, most periodontal ligament arrangement and PDL width was repaired and fiber density increased. In MT stain, mineralization of immature bone on the alveolar crest was progressed. In pulp, vacuole and hyperemia was diminished and fibrotic change was diminished 4. After 3 week periodontal ligament has more repair ability than pulp tissue. pulp was involved with vacuolization and fibrosis, so it takes more time for repair.