1.Three-dimensional finite element analysis on reciprocal action by torque application in maxillary archwire.
Chee Il HWANG ; Cheong Hoon SUHR
Korean Journal of Orthodontics 1994;24(2):479-508
This study was designed to investigate the reciprocal movement which was derived form application of active torque in ideal arch wire by computer-aided three-dimensional finite element analysis of maxillary teeth and surrounding periodontal ligament composed of 2617 elements and 3725 nodes. Ideal arch wire model was also made using the beam elements and the contact between the wire and the bracket slot was made using the gap element. In this study non-linear elastic behaviors of contact between the wire and the bracket slot were considered on. We put the active torque between the lateral and central incisor and between the second premolar and the first molar with/without cinch-back. The results were expressed by quantitative and visible ways. The findings of this study were as follows: 1. Reciprocal actions to active torque were complex system consisting of a combination of counter-torque, bucco-lingual linear displacement and tipping, rotation of the teeth, occluso-gingival linear displacement. 2. When active anterior crown labial torque was applied, crown labial tippings of the lateral were the greatest, and those of the central incisor was the next. Crown lingual tippings of the canine and the first premolar, mesial rotations and extrusion of the lateral and distal rotations and intrusion of the canine occurred. When anterior torque with the cinch-back was applied, amount of crown labial tippings of the lateral and central incisor were reduced. Amount of crown lingual tipping of the canine and the first premolar were increased. Mesial tippings and mesial rotations of the second molar occurred. 3. When active posterior crown lingual torque was applied, crown lingual tippings of the first molar were the greatest, and crown labial tippings of the second premolar and the first premolar were the next, the crown lingual tipping of the second molar were a little. Mesial rotations of the second premolar occurred but those of the first premolar didn't occurred.
Bicuspid
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Crowns
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Finite Element Analysis*
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Incisor
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Molar
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Periodontal Ligament
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Tooth
;
Torque*
2.Fluoroscopy-Guided Endovenous Sclerotherapy Using a Microcatheter Prior to Endovenous Laser Ablation: Comparison between Liquid and Foam Sclerotherapy for Varicose Tributaries.
Sang Woo PARK ; Ik Jin YUN ; Jae Joon HWANG ; Song Am LEE ; Jun Seok KIM ; Hyun Keun CHEE ; Il Soo CHANG
Korean Journal of Radiology 2014;15(4):481-487
OBJECTIVE: To compare the efficacy and adverse effects of endovenous foam sclerotherapy (EFS) and liquid sclerotherapy (ELS) using a microcatheter for the treatment of varicose tributaries. MATERIALS AND METHODS: From December 2007 to January 2009, patients with venous reflux in the saphenous vein were enrolled. The foam or liquid sclerosant was injected through a microcatheter just before endovenous laser ablation (EVLA). Patients were evaluated for the technical success, clinical success, and procedure-related complications during the procedure and follow-up visits. RESULTS: A total of 94 limbs were included: 48 limbs (great saphenous vein [GSV], 35; small saphenous vein [SSV], 13) were managed using EFS and EVLA (foam group; FG), and 46 limbs (GSV, 37; SSV, 9) were treated by ELS and EVLA (liquid group; LG). Varicose tributaries demonstrated complete sclerosis in 92.7% with FG and in 71.8% with LG (p = 0.014). Bruising (78.7% in FG vs. 73.2% in LG, p > 0.05), pain or tenderness (75.6% in FG vs. 51.2% in LG, p = 0.0237) were noted. Hyperpigmentation (51.2% in FG vs. 46.2% in LG, p > 0.05) was found. CONCLUSION: Endovenous foam sclerotherapy using a microcatheter is more effective than ELS for eliminating remnant varicose tributaries prior to EVLA. However, EFS is more commonly associated with local complications such as pain or tenderness than ELS. Furthermore, both techniques seem to prolong the duration of hyperpigmentation along with higher costs.
Catheters/adverse effects
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Femoral Vein
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Fluoroscopy/methods
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Humans
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Laser Therapy/methods
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Radiography, Interventional/methods
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*Saphenous Vein/radiography/surgery
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Sclerosing Solutions/*administration & dosage/chemistry
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Sclerotherapy/adverse effects/instrumentation/*methods
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Treatment Outcome
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Varicose Veins/radiography/*therapy
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Venous Insufficiency/surgery
3.Early Results of Endovenous Ablation with a 980-nm Diode Laser for an Incompetent Vein of Giacomini.
Sang Woo PARK ; Song Am LEE ; Jae Joon HWANG ; Ik Jin YUN ; Jun Seok KIM ; Seong Hwan CHANG ; Hyun Keun CHEE ; Il Soo CHANG
Korean Journal of Radiology 2011;12(4):481-486
OBJECTIVE: We wanted to evaluate the effectiveness of endovenous ablation of the incompetent vein of Giacomini using a 980-nm diode laser. MATERIALS AND METHODS: A total of 18 patients (18 limbs, 4%) had the incompetent vein of Giacomini. Retrograde reflux originating from the great saphenous vein was noted in sixteen limbs and paradoxical diastolic anterograde reflux from the saphenopopliteal junction was observed in two limbs. After tumescent anesthesia, laser ablation using a 980-nm wavelength laser fiber was performed under ultrasound and/or fluoroscopic guidance. Patients were evaluated clinically and with duplex ultrasound at one week and at one, three, six and twelve months after laser ablation for the technical and clinical success. RESULTS: In the 18 limbs, the technical success rate was 100%. Continued closure of the vein of Giacomini was seen in 18 of 18 limbs after one month, in 12 of 12 limbs after three and six months and in six of six limbs after twelve months. No recanalization of the vein and no major complications occurred. CONCLUSION: Endovenous laser ablation with a 980-nm wavelength is an effective and safe procedure for treating an incompetent vein of Giacomini.
Adult
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Female
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Fluoroscopy
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Humans
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Laser Therapy/*methods
;
Lasers, Semiconductor
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Leg/*blood supply
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Male
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Middle Aged
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Saphenous Vein/*surgery
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Treatment Outcome
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Venous Insufficiency/*surgery
4.The Association between Symptoms of Autonomic Neuropathy and the Heart Rate Variability in Diabetics.
Min Young CHUN ; Hoon Ki PARK ; Hwan Sik HWANG ; Jae Il HAN ; Young Joon CHEE ; Jong Sill LEE
Korean Journal of Family Medicine 2011;32(5):292-298
BACKGROUND: There are few tools to detect the diabetic autonomic neuropathy at an earlier stage. This study was conducted to investigate the association between symptoms of autonomic neuropathy and the heart rate variability (HRV) in diabetics. METHODS: Study subjects consisted of 50 diabetic patients and 30 outpatient hospital control patients at a university family medicine department. The patients completed a Korean version of composite autonomic symptom scale (COMPASS). Electrocardiography was recorded in the supine position, on standing, and during deep breathing, for 5 minutes each. HRV of frequency domain was calculated by power spectral analysis. RESULTS: The COMPASS score was higher in female diabetic patients compared with that in controls. Among 50 diabetic patients, the total COMPASS score correlated positively with normalized low frequency (LF) score (normalized units, n.u.) (r = 0.62, P < 0 .001) and low frequency/high frequency (LF/HF) (r = 0.77, P < 0.001), negatively with normalized HF score (n.u.) (r = -0.59, P < 0.001) and RMSSD (square root of the mean of the sum of the square of differences between adjacent NN interval; r = -0.33, P = 0.031). The decrease in LF (n.u) and the increase in HF (n.u) by deep breathing from the supine position were higher in diabetic patients compared with those in controls. The increase in LF (n.u) and the decrease in HF (n.u) by standing from the supine position were lower in diabetic patients compared with those in controls. CONCLUSION: The COMPASS score correlated with some component score of the HRV in diabetics. The HRV may be used as a tool to detect diabetic autonomic neuropathy by augmentation with position change.
Diabetic Neuropathies
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Electrocardiography
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Female
;
Heart
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Heart Rate
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Humans
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Outpatients
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Respiration
;
Supine Position
5.The Primary Patency and Fracture Rates of Self-Expandable Nitinol Stents Placed in the Popliteal Arteries, Especially in the P2 and P3 Segments, in Korean Patients.
Il Soo CHANG ; Hyun Keun CHEE ; Sang Woo PARK ; Ik Jin YUN ; Jae Joon HWANG ; Song Am LEE ; Jun Seok KIM ; Seong Hwan CHANG ; Hong Geun JUNG
Korean Journal of Radiology 2011;12(2):203-209
OBJECTIVE: We wanted to evaluate the status of self-expandable nitinol stents implanted in the P2 and P3 segments of the popliteal artery in Korean patients. MATERIALS AND METHODS: We retrospectively analyzed 189 consecutive patients who underwent endovascular treatment for stenoocclusive lesions in the femoropopliteal artery from July 2003 to March 2009, and 18 patients who underwent stent placement in popliteal arterial P2 and P3 segments were finally enrolled. Lesion patency was evaluated by ultrasound or CT angiography, and stent fracture was assessed by plain X-rays at 1, 3, 6 and 12 months and annually thereafter. RESULTS: At the 1-month follow-up, stent fracture (Type 2) was seen in one limb (up to P3, 1 of 18, 6%) and it was identified in seven limbs at the 3-month follow-up (Type 2, Type 3, Type 4) (n = 1: up to P2; n = 6: P3). At the 6-month follow-up, one more fracture (Type 1) (up to P3) was noted. At the 1-year follow-up, there were no additional stent fractures. Just four limbs (up to P2) at the 2-year follow-up did not have stent fracture. The primary patency was 94%, 61% and 44% at 1, 3 and 6 months, respectively, and the group with stent implantation up to P3 had a higher fracture rate than that of the group that underwent stenting up to P2 (p < 0.05). CONCLUSION: We suggest that stent placement up to the popliteal arterial P3 segment and over P2 in an Asian population can worsen the stent patency owing to stent fracture. It may be necessary to develop a stent design and structure for the Asian population that can resist the bending force in the knee joint.
Aged
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Aged, 80 and over
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Alloys
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Angiography
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Arterial Occlusive Diseases/radiography/*therapy/ultrasonography
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Chi-Square Distribution
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Female
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Fluoroscopy
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Humans
;
Korea
;
Leg/blood supply
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Male
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Middle Aged
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Peripheral Vascular Diseases/radiography/*therapy/ultrasonography
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*Popliteal Artery
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Prosthesis Failure
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Retrospective Studies
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*Stents
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Tomography, X-Ray Computed
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Ultrasonography, Doppler, Color
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Ultrasonography, Doppler, Duplex
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Vascular Patency