• The korean journal of orthodontics
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• v.37 no.6
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• pp.407-420
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• 2007

The aim of this study was to compare the differences in closing extraction spaces between maxillary first premolar and second premolar extractions using 3-dimensional finite element analysis (FEA). Methods: Maxillary artificial teeth were selected according to Wheeler's dental anatomy. The size and shape of each tooth, bracket and archwire were made from captured real images by a 3D laser scanner and FEA was performed with a 10-noded tetrahedron. A $10^{\circ}$ gable bend was placed behind the bull loop on a $0.017"{\times}0.025"$ archwire. The extraction space was then closed through 12 repeated activating processes for each 2mm of space. Results and Conclusions: The study demonstrated that the retraction of anterior teeth was less for the second premolar extraction than for the first premolar extraction. The anterior teeth showed a controlled tipping movement with slight extrusion, and the posterior teeth showed a mesial-in rotational movement. For the second premolar extraction, buccal movement of posterior teeth was highly increased.

• Journal of the Korean Arthroscopy Society
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• v.10 no.2
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• pp.148-152
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• 2006

Purpose: The purpose of this study was to investigate the distribution of the diameter of four strand autologous hamstring tendon and to identify the factors related to the diameter. Materials and Methods: Between December 2004 and July 2006, 66 patients underwent anterior cruciate ligament reconstruction using autologous hamstring tendon. Sixty one patients were male and the other 5 patients were female. Both semitendinosus and gracilis tendon were harvested in every case. Harvested two tendons were folded once together to create a four strand double loop graft and were passed through cylindrical sizer to measure their diameter. Parameters such as sex, age, height and weight were analyzed for their correlation with the diameter of the graft. Results: The diameter of the graft ranged from 6 mm to 10 mm. The graft with the diameter of 8 mm was most common and the average diameter of all the grafts was $7.85{\pm}0.92mm$. Seven patients (10.6%) had a graft with the diameter of 6 mm, which is considered too thin to be ideal one. No statistically significant correlation was found between age of the patient and the diameter of the graft. However, the diameter of the graft was significantly correlated with sex, height and weight of the patient. Female patients had a significant tendency to have thinner hamstring tendons. Both small height and light weight of the patients were correlated with thinner hamstring tendons significantly. Conclusion: Sex, height and weight of the patients were the factors that had a statistically significant correlation with the diameter of the graft. Being aware of the risk factors related with harvesting exceedingly thin hamstring tendon prior to anterior cruciate ligament reconstruction, one can utilize wide range of options in selecting an optimal graft.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.933-948
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• 1996

The purpose of this study was to examine the anatomic structures of the mandible-inferior alveolar canal, mental foramen, mental canal-with panoramic radiography and conventional tomography and to compare both radiographic techniques in conjunction with endosseous implants. In this study 14 adult dentulous mandibles -27 cases of right and left side of mandibles- were examined and the results were as follows. 1. The distance between superior border of the inferior alveolar canal and the alveolar ridge crest showed a decreasing tendency from the mental foramen to 4cm posterior to the mental foramen. 2. The mean diameter of the inferior alveolar canal was $4.11{\pm}0.50mm$ with panoramic radiography and $3.29{\pm}0.59mm$ with conventional tomography. 3. The inferior border of the inferior alveolar canal and inferior border of the mandible was closest at 2cm posterior to the mental foramen but it was not statistically significant. the mean distance was $1l.64{\pm}2.95mm$ in panoramic radiography and $1l.68{\pm} 2.91mm$ in conventional tomography. 4. The inferior alveolar canal located lingually in bucco-lingual direction 16%(mental foramen), 54%(lcm posterior to the mental foramen), 68%(2cm posterior to the mental foramen), 50%(3cm posterior to mental foramen), 55%(4cm posterior to the mental foramen). 5. Mean length of the anterior loop of the mental canal was 2.73mm, and the loop below 2mm was 35% and 15% of mental canal was invisible in panoramic radiography. 6. The minimum interforaminal distance was 56.7mm, the maximum distance was 73.2mm and the mean distance was 66.42mm in panoramic radiography. 7. The mean distance between midpoint of the mental canal and alveolar ridge crest was 16.24mm and the mean buccolingual angulation of the mental canal was $52.98^{\circ}$ in conventional tomography. 8. In comparison of panoramic radiography and conventional tomography, inferior alveolar canal is better visualized with conventional tomography than panoramic radiography from the mental foramen to the 2cm posterior to the mental foramen, while visiblity of conventional tomography prominently decreased in 4cm posterior to the mental foramen and alveolar ridge crest is better visualized with panoramic radiography than conventional radiography at the mental foramen and at 4cm posterior to the mental foramen. In radiologic examination of anatomic structures of the mandible for endosseous implants, panoramic radiography and conventional tomography can be effectively used when it is used to overcome the anatomic limitations.

• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.77-83
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• 1981

The purpose of this study was to observe the bonding strength between tooth surface (enamel and dentin) and restorative filling materials which are two composite resins (Clearfil and Concise) and Glass ionomer cement, after etching with 50% phoshoric acid and 37% citric acid. To measure the bonding strength in enamel, the labial surface of upper anterior tooth was cut flatly with using carborundum disk and polished with sand paper disk, and to measure in dentin, the dentin surface was prepared by grinding upper part of posterior tooth horizontally. After washing the tooth surface with water and drying with air blast, the prepared tooth surface was etched. In glass ionomer cement, 50% phosphoric acid and 37% citric acid were used, in Clearfil 40% phosphoric acid was used and in Concise, 50% phosphoric acid and 37% citric acid were used as etchant for 1 minute. After the copper band which is 5 mm in diameter and 5 mm in height was fixed on the prepared surface and each filling material was inserted into the copper band, the hooking loop was inserted into filled material in the copper band before setting to make it easily that the load is applied on the specimen. After all specimens were immersed in water at $37^{\circ}C$ for 1 week, this specimen was placed on the load cell of tensile test apparatus, and specimen was pulled at the cross-head speed of 0.8 mm per minute. The following results were obtained 1) In glass ionomer cement, the bond strength obtained by 37% citric acid was higher than one obtained by 50% phosphoric acid in enamel and dentin surfaces. The bond strength obtained in non-etched surface was much less than one by etchants in enamel and dentin surface. 2) In Clearfil, the bond strength obtained by 40% phosphoric acid was 4 times more than one obtained by non etch ant. 3) In Concise, the bond strength obtained by 50% phosphoric acid was almost same as one obtained by 37% citric acid, and the bond strength obtained by non etch ant was much less than one obtained by etchants.

• Journal of Audiology & Otology
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• v.25 no.3
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• pp.152-158
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• 2021

Background and Objectives: Balance control is maintained in stationary and dynamic conditions, with coordinated muscle responses generated by somatosensory, vestibular, and visual inputs. This study aimed to investigate how the vestibular system is affected in the presence of an optical illusion to better understand the interconnected pathways of the visual and vestibular systems. Subjects and Methods: The study involved 54 young adults (27 males and 27 females) aged 18-25 years. The recruited participants were subjected to the cervical vestibular evoked myogenic potentials (cVEMP) test and video head impulse test (vHIT). The cVEMP and vHIT tests were performed once each in the absence and presence of an optical illusion. In addition, after each test, whether the individuals felt balanced was determined using a questionnaire. Results: cVEMP results in the presence of the optical illusion showed shortened latencies and increased amplitudes for the left side in comparison to the results in the absence of the optical illusion (p≤0.05). When vHIT results were compared, it was seen that the right lateral and bilateral anterior canal gains were increased, almost to 1.0 (p<0.05). Conclusions: It is thought that when the visual-vestibular inputs are incompatible with each other, the sensory reweighting mechanism is activated, and this mechanism strengthens the more reliable (vestibular) inputs, while suppressing the less reliable (visual) inputs. As long as the incompatible condition persists, the sensory reweighting mechanism will continue to operate, thanks to the feedback loop from the efferent vestibular system.

• Korean Journal of Audiology
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• v.25 no.3
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• pp.152-158
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• 2021

Background and Objectives: Balance control is maintained in stationary and dynamic conditions, with coordinated muscle responses generated by somatosensory, vestibular, and visual inputs. This study aimed to investigate how the vestibular system is affected in the presence of an optical illusion to better understand the interconnected pathways of the visual and vestibular systems. Subjects and Methods: The study involved 54 young adults (27 males and 27 females) aged 18-25 years. The recruited participants were subjected to the cervical vestibular evoked myogenic potentials (cVEMP) test and video head impulse test (vHIT). The cVEMP and vHIT tests were performed once each in the absence and presence of an optical illusion. In addition, after each test, whether the individuals felt balanced was determined using a questionnaire. Results: cVEMP results in the presence of the optical illusion showed shortened latencies and increased amplitudes for the left side in comparison to the results in the absence of the optical illusion (p≤0.05). When vHIT results were compared, it was seen that the right lateral and bilateral anterior canal gains were increased, almost to 1.0 (p<0.05). Conclusions: It is thought that when the visual-vestibular inputs are incompatible with each other, the sensory reweighting mechanism is activated, and this mechanism strengthens the more reliable (vestibular) inputs, while suppressing the less reliable (visual) inputs. As long as the incompatible condition persists, the sensory reweighting mechanism will continue to operate, thanks to the feedback loop from the efferent vestibular system.

• The korean journal of orthodontics
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• v.32 no.1 s.90
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• pp.9-18
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• 2002

The present study hypothesized that the double keyhole looped archwire plays a positive role for the sake of translatory movement and/or controlled tipping of upper 6 anteriors, and secures anchorage control as well. The purposes of the study were to evaluate the changes in lateral cephalograms during orthodontic treatment with DKHLs and to compare the skeletal & dental changes before- & after-treatment. The materials of this study were lateral cephalograms of 20 adult patients with upper dentoalveolar protrusion both in class I and in class II Division1 malocclusion. Lateral cephalograms were taken before and after orthodontic treatment with upper 1st bicuspid extraction and DKHLs. The results were obtained as follows : 1. There were no statistically significant differences in skeletal measurement except SNB and PTFH between before- & after-treatment. The major changes were in dentoalveolar region. 2. After treatment, there were statistically significant decrease in dental measurement except interincisal angle. 3. Both upper & lower lip protrusion was decreased. 4. There were statistically differences in upper anterior crown horizontal & root vertical dimension(7.08 ${\pm}$ 2.14 mm, 2.38 ${\pm}$ 1.15 mm, p<0.01). 5. There were statistically differences in upper posterior dental(both crown & root) horizontal dimension(2.48 ${\pm}$ 0.99 mm, 2.05 ${\pm}$ 0.91 mm, p<0.01).

• Journal of Chest Surgery
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• v.12 no.3
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• pp.281-288
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.289-296
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.697-709
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• 1997

This study was designed to investigate the stress intensity and distribution produced by 1mm activation of retraction archwire with $0^{\circ},\;7^{\circ},\;14^{\circ}$ torque and application of high polk J-hook headgear during retraction of four maxillary incisors using the photoelastic stress analysis. The photoelastic model was made with a PL-3 type epoxy resin which was substituted by alveolar bone portion. Each retraction archwire was fabricated from .020' X .025' stainless steel wire which had vertical loops in 7mm height and hooks for high pull J-hook headgear between central and lateral incisors. The high pull J-hook headgear was applied 35 degree backward and upward to occlusal plane with 200gm pet each side The findings of this study were as follows: 1. In case of $0^{\circ}$ torque, the stress was distributed from cervical 1/8 to apex of roots of central and lateral incisors which were the forms of arc mode. When the high pull J-hook headgear was applied, the stress distributed by arc mode was presented from cervical 1/2 to apex of roots of central and lateral incisors. And the stress distributed by following the root surface was presented from alveolar crest to cervical 1/2 of roots of central and lateral incisors. The stress between apecies of central and Lateral incisors was presented also. 2. In case of $7^{\circ}$ torque, the stress distributed by arc mode was presented from cervical 1/2 to apex of roots of central and lateral incisors. And the stress distributed by following the root surface was presented from alveolar crest to cervical 1/2 of roots of central and lateral incisors. When the high pull J-hook headgear was applied, the stress distributed by following the root surface was presented mote apically than without headgear. The stress between apecies of central and lateral incisors was presented also. 3. In case of $14^{\circ}$ torque, the stress distributed by following the root surface was Presented from alveolar crest to apex of roots of central and lateral incisors. When the high pull J-hook headgear was applied, the stress distributed by following the root surface was presented stronger than without headgear The stress between apecies of central and lateral incisors was presented also.