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 ; Crowns ; Finite Element Analysis* ; Incisor ; Molar ; Periodontal Ligament ; Tooth ; Torque*

The purpose of this study was to evaluate the effects of the chincap therapy on the craniofacial structure in persons with skeletal Class III malocclusion. The patients selected for this study were treated with extra-oral chincap therapy only. Both control and treatment samples were obtained from Seoul National University Hospital where these longitudinal data were gathered. 35 treated patients and 14 control patients were studied. The mean ages at the 1st evaluation was 8 years 3 months in the treatment sample and 9 years 4 months in the control sample. The duration of chin cap therapy was variable but averaged 2 years of treatment. Post-treatment observation procedeeded for 1 year 2 months. Active treatment and post treatment effects were evaluated. The results were as follows: 1. Neither significant restraint nor acceleration of growth was found in the cranial base and maxilla during treatment. 2. A distal rotation of the mandibular complex was seen. 3. Some amount of restraint of growth was found in mandibular body length, ramus height, mandibular length during treatment. 4. The gonial angle was reduced. 5. After removal of the chin-cap, forward displacement of the mandible took place.
Acceleration ; Chin ; Humans ; Malocclusion* ; Mandible ; Maxilla ; Seoul ; Skull Base

Operators of hospital sterilizers who use ethylene oxide (EtO) were studied to determine the exposure of EtO level and the frequency of sister chromatid exchanges (SCEs) from June 12 to July 20, 1997. To evaluate SCEs in the peripheral blood cells, we selected 22 workers at the central supply room of 4 university hospitals and 22 unexposed workers at the same hospitals according to match sex, age, and smoking habit and also did questionnaires. The mean air concentrations (8-hr TWA) of EtO at 4 university hospitals were less than 1 ppm. The SCE frequencies in exposed workers to EtO and controls were normally distributed. The SCE frequencies in exposed workers to EtO and controls were 6.42+/-.63, 5.86+/-.69, respectively and their differences were statistically significant (p=0.0093). But there were no statistically significant differences in smoking, alcohol intake, coffee drinking. Especially smokers who exposed to EtO were increased SCE statistically significant than the exposed group who did not smoke.
Blood Cells ; Coffee ; Drinking ; Ethylene Oxide* ; Hospitals, University ; Humans ; Occupations* ; Questionnaires ; Siblings* ; Sister Chromatid Exchange* ; Smoke ; Smoking

This study was started to find out if plasma malondialdehyde(MDA), alpha-tocopherol and erythrocyte superoxide dismutase(SOD) activity could be markers of biological activity resulting from exposed to lead in workers. Blood samples were randomly obtained from lead -exposed workers(n=29), CO2 welders(n=60) and office workers(n=60). We used whole blood to analyse blood lead with atomic absorption spectrophotometer. Superoxide dismutase activity in erythrocyte was measured with spetrophotometer. MDA and alpha-tocopherol in plasma were measured with high performance liquid chromatography. Lead-exposed workers was significantly high in blood lead concentration(29.37 ng/dl) compared with welders(6.42 ng/dl) and office workers(5.01 ng/dl). The level of plasma MDA was significantly higher in the lead-exposed workers(1.87 nmol/g cholesterol) than the welders(1.41 nmol/g cholesterol) and office workers(1.41 nmol/g cholesterol). Erythrocyte SOD activity in lead-exposed workers(56.80 U/g Hb) was significantly increased than those of welders(37.63 U/g Hb) and office workers(20.47 U/g Hb). The plasma alpha-tocopherol level of lead-exposed workers(4.93 ng/g cholesterol) was statistically different from welders(4.25 ng/g cholesterol) and office workers(4.28 ng/g cholesterol). Neither age nor smoking was related to SOD or MDA level. Blood lead was significantly correlated with erythrocyte SOD activity(r=0.405), plasma MDA(r=0.296) and alpha-tocopherol(r=0.207). Plasma MDA was also significantly correlated with SOD (r=0.217). In multiple regression analysis, the change of MDA and SOD activity level related to the blood lead concentration. These results suggested that the increase of plasma MDA and erythrocyte SOD activity in lead-exposed workers had a close relationship with the oxidative stress induced by lead.
Absorption ; alpha-Tocopherol ; Antioxidants* ; Chromatography, Liquid ; Erythrocytes ; Lipid Peroxidation* ; Oxidative Stress ; Plasma ; Smoke ; Smoking ; Superoxide Dismutase ; Superoxides

Biliary adenofibromas are rare biliary epithelial tumors that are classified as benign. Nevertheless, some cases have been reported to show malignant transformations. The radiologic findings of biliary adenofibromas and their malignant transformation are not well-established because of their rarity. We present a case of a cholangiocarcinoma arising from a biliary adenofibroma assessed using ultrasonography, CT, and MRI. The differential diagnoses include other hepatic tumors.

Biliary adenofibromas are rare biliary epithelial tumors that are classified as benign. Nevertheless, some cases have been reported to show malignant transformations. The radiologic findings of biliary adenofibromas and their malignant transformation are not well-established because of their rarity. We present a case of a cholangiocarcinoma arising from a biliary adenofibroma assessed using ultrasonography, CT, and MRI. The differential diagnoses include other hepatic tumors.

PURPOSE: The pathophysiologic mechanisms and risk factors of renal functional deterioration are still controversial. We analyzed the factors associated with renal failure in children with primary vesicoureteral reflux. METHODS: The medical records of 166 children who were diagnosed with primary vesicoureteral reflux from Jan. 1985 to Dec. 1996 in the Department of Pediatrics, Seoul National University Children's Hospital were reviewed retrospectively. The patients were divided into two groups according to renal function: patients with renal failure(RF group) and patients with normal renal function(NRF group). RESULTS: Eighteen(11%) were classified as RF group, and 16(89%) of them were male. Sixteen (89%) of RF group revealed decreased renal function at the time of diagnosis. There was no past history of documented urinary tract infection in 16(89%) of RF group. Patients of RF group had a higher grade of reflux as compared with those of NRF group. Proteinuria and hypertension were found in 16(89%) and 6(33%) of RF group, respectively, while no NRF patients had proteinuria or hypertension. Renal functional deterioration had progressed to end-stage renal disease in 6(33%) of RF group during a mean follow-up of 4.4+/-2.7(range 0.5-12) years. CONCLUSION: Reflux nephropathy and renal scar in children can be prevented, in some cases, by early diagnosis of vesicoureteral reflux and prophylaxis of urinary tract infection. Regular check up for proteinuria and hypertension is essential for early detection of renal dysfunction. However, in other patients, especially in male, renal dysfunction can develop independently on urinary tract infection.
Child* ; Cicatrix ; Diagnosis ; Early Diagnosis ; Follow-Up Studies ; Humans ; Hypertension ; Kidney Failure, Chronic ; Male ; Medical Records ; Pediatrics ; Proteinuria ; Renal Insufficiency* ; Retrospective Studies ; Risk Factors ; Seoul ; Urinary Tract Infections ; Vesico-Ureteral Reflux*

Pulmonary hemorrhage is a rare but possibly fatal complication of systemic lupus erythematosus (SLE). We report a case of massive pulmonary hemorrhage in a 14-year-old boy recently diagnosed as SLE. He developed massive pulmonary hemorrhage during the courses of i.v. methylprednisolone pulse therapy, and did not respond to i.v. cyclophosphamide. However, he rapidly improved through the use of plasmapheresis. Although various factors can precipitate pulmonary hemorrhage in SLE, our case was probably caused by an immune mediated mechanism since the hemorrhage responded promptly to plasmapheresis. This case illustrates the importance of plasmapheresis in the treatment of pulmonary hemorrhage which is not improved by methylprednisolone and cyclophosphamide. We report this case with a brief review of the related literatures.
Adolescent ; Child* ; Cyclophosphamide ; Hemorrhage* ; Humans ; Lupus Erythematosus, Systemic* ; Male ; Methylprednisolone ; Plasmapheresis*

Pulmonary hemorrhage is a rare but possibly fatal complication of systemic lupus erythematosus (SLE). We report a case of massive pulmonary hemorrhage in a 14-year-old boy recently diagnosed as SLE. He developed massive pulmonary hemorrhage during the courses of i.v. methylprednisolone pulse therapy, and did not respond to i.v. cyclophosphamide. However, he rapidly improved through the use of plasmapheresis. Although various factors can precipitate pulmonary hemorrhage in SLE, our case was probably caused by an immune mediated mechanism since the hemorrhage responded promptly to plasmapheresis. This case illustrates the importance of plasmapheresis in the treatment of pulmonary hemorrhage which is not improved by methylprednisolone and cyclophosphamide. We report this case with a brief review of the related literatures.
Adolescent ; Child* ; Cyclophosphamide ; Hemorrhage* ; Humans ; Lupus Erythematosus, Systemic* ; Male ; Methylprednisolone ; Plasmapheresis*

Duodenal ulcers and acute pancreatitis are two of the most commonly encountered gastrointestinal diseases among the general population. However, duodenal ulcer-induced pancreatitis is very rarely reported worldwide. This report elaborates on a distinct medical treatment that contributes to partial or complete treatment of acute pancreatitis induced by a duodenal ulcer scar.
Cicatrix ; Duodenal Ulcer* ; Duodenum ; Gastrointestinal Diseases ; Pancreatitis* ; Stents ; Ulcer