1.Finite element stress analysis of implant prosthesis with internal connection between the implant and the abutment.
Jong Kwan AHN ; Kee Sung KAY ; Chae Heon CHUNG
The Journal of Korean Academy of Prosthodontics 2004;42(4):356-372
STATEMENT OF PROBLOM: In the internal connection system the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. PURPOSE: The purpose of this study was to assess the loading distributing characteristics of 3 implant systems with internal connection under vertical and inclined loading using finite element analysis. MATERIAL AND METHOD: Three finite element models were designed according to the type of internal connection of ITI(model 1), Friadent(model 2), and Bicon(model 3) respectively. This study simulated loads of 200N in a vertical direction (A), a 15 degree inward inclined direction (B), and a 30 degree outward inclined direction (C). RESULT: The following results have been made based on this numeric simulations. 1. The greatest stress showed in the loading condition C of the inclined load with outside point from the centric cusp tip. 2. Without regard to the loading condition, the magnitudes of the stresses taken at the supporting bone, the implant fixture, and the abutment were greater in the order of model 2, model 1, and model 3. 3. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture, and lower stress was taken at the cancellous bone. 4. The stress of the implant fixture was usually widely distributed along the inner surface of the implant fixture contacting the abutment post. 5. The stress distribution pattern of the abutment showed that the great stress was usually concentrated at the neck of the abutment and the abutment post, and the stress was also distributed toward the lower part of the abutment post in case of the loading condition B, C of the inclined load. 6. In case of the loading condition B, C of the inclined load, the maximum von Misess stress at the whole was taken at the implant fixture both in the model 1 and model 2, and at the abutment in the model 3. 7. The stress was inclined to be distributed from abutment post to fixture in case of the internal connection system. CONCLUSION: The internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, and the abutment according to the abutment connection form had differenence among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the a butment post.
Finite Element Analysis
;
Mandible
;
Neck
;
Prostheses and Implants*
2.A STUDY ON THE PHYSICAL PROPERTIES AND VOLUMETRIC STABILITY OF SR-IVOCAP RESIN SYSTEM.
Sung Sik EUN ; Hyeog Sin KWEON ; Chae Heon CHUNG
The Journal of Korean Academy of Prosthodontics 1998;36(3):453-467
This study helps to clarify conflicting reports by comparing the physical properties and accuracy of complete denture processed by the pack and press technique, continuous-pressure injection technique(SR-Ivocap system) and Mark press technique. The 6 different specimens have been evaluated using the SEM, Impact test, DSC (Differential Scanning Calorimetry) and DMTA(Dynamic Mechanical Thermal Analysis). Each sample was made of SR-Ivocap resin and QC-20 resin by different processing methods. The results were as follows ; 1. As the result of the observation on the fracture surface of resin by use of SEM, sample SR-Ivocap resin cured by continuous pressure injection method showed the most homogeneous structure. This is why molecules in SR-Ivocap resin have no orientation. 2. As the result of the Impact test in order to measure the deformity, fracture energy and impact resistance of resin, the samples with QC-20 acrylic resin and SR-Ivocap resin cured by continuous pressure injection method were exellent. 3. In consequence of measuring alpha-glass transition temperature by use of DSC on the basis of temperature change, the glass transition temperatures of sample QC-20 resin cured by pack and press method and sample SR-Ivocap resin cured by continuous pressure injection method were very similar. Thus volumetric stability could not be evaluated only by glass transition temperature. 4. In comparing volumetric stability data by DMTA, the glass transition temperature(Tg) showed 137.88degrees C at sample QC-20 resin cured by pack and press method and 139.78degrees C at sample SR-Ivocap resin cured by continuous pressure injection method. Therefore sample SR-Ivocap resin cured by continuous pressure injection method seems to be superior to sample QC-20 resin cured by pack and press method in the dimensional stability at high temperature. 5. In comparing storage modulus data by DMTA, the storage modulus of sample SR-Ivocap resin cured by continuous pressure injection method was higher than that of sample QC-20 resin cured by pack and press method. So, sample SR-Ivocap resin cured by continuous pressure injection method seems to be superior to sample QC-20 resin cured by pack and press method in impact strength.
Congenital Abnormalities
;
Denture, Complete
;
Glass
;
Transition Temperature
3.Bilateral Diffuse Radiation Pneumonitis Caused by Unilateral Thoracic Irradiation: A Case Report.
Sung Heon SONG ; Yoon Jung OH ; Chang Won HA ; Soo Min CHAE
Journal of Lung Cancer 2012;11(2):97-101
Radiation therapy is one of the most important therapeutic modalities for the treatment of lung cancer. Radiation pneumonitis is one of the important complications associated with radiotherapy for lung cancer. Radiation pneumonitis is generally limited to the irradiated lung and is manifested by the insidious onset of dry cough, dyspnea, and mild fever, resulting in damage and edematous changes of alveolar structures on histologic inspection. Clinically, diffuse bilateral radiation pneumonitis accompanied with acute symptoms after unilateral thoracic irradiation appears very rarely. Histopathologic examinations for the diagnosis of out-of-field radiation pneumonitis are rarely performed. We herein describe a case of extensive bilateral radiation pneumonitis which developed acutely after salvage radiotherapy for squamous cell carcinoma in the left upper lobe of the lung. The condition was confirmed by a diagnostic help of histopathologic findings.
Carcinoma, Squamous Cell
;
Cough
;
Dyspnea
;
Fever
;
Lung
;
Lung Neoplasms
;
Radiation Pneumonitis
4.Prevalence of atrial fibrillation in general population in Kangwon Province.
Myoung Kuk JANG ; Ja Young LEE ; Seong Gyun KIM ; Kyu Heung CHO ; Yong Sang YANG ; Dong Seok YOON ; Sung Heon CHAE
Journal of the Korean Academy of Family Medicine 2001;22(2):178-183
BACKGROUND: Atrial fibrillation is the commonest arrhythmia seen in clinical practice. However, there have been no epidemiologic data on its prevalence in general population of Korea. We performed this study to investigate the prevalence of atrial fibrillation in Korea. METHODS: From March 1, 1999 to July 31, 2000, Kangwon Branch, Korea Association of Health (KAH) parformed electrocardiograms to investigate the health status in the general public in Kangwon Province. We analyzed these data by of chi square(2) test. RESULTS: A total of 45,133 persons participated in the health screening performed by KAH. The number of persons above 40 years old were 13,768, with men and women 6,367 (46.2%) and 7,401 (53.8%)respectively. Prevalence among those above 40 years old was 0.72% and the prevalence among men, 0.96% (61 persons) was significantly higher than that of women, 0.51% (38 persons)(p<0.01). In the group above 60 years old with the prevalence of 1.24%, a similar phenomenon was observed with 1.57% (40 persons) in men and 0.97% (29 persons) in women (p<0.05). CONCLUSION: Prevalence of atrial fibrillation became higher as age increased, specifically in persons older than 40 years.
Adult
;
Arrhythmias, Cardiac
;
Atrial Fibrillation*
;
Electrocardiography
;
Female
;
Gangwon-do*
;
Humans
;
Korea
;
Male
;
Mass Screening
;
Middle Aged
;
Prevalence*
5.Age-related Alterations of Bcl-2, Bax and Apoptosis in Ischemic-reperfused Rat Tibialis Anterior Muscles.
Youn Kyoung SEO ; Jong Heon KIM ; Hyun Sung LEEM ; Chae Soo SHIN ; Doo Jin PAIK
Korean Journal of Physical Anthropology 2003;16(2):97-107
Prolonged ischemic-reperfusion induces cellular damages and apoptosis in rat skeletal muscle. Such injury takes place in the phase of reperfusion following ischemia induction in part via regulating of apoptosis-related gene inductions. Among apoptosis-related gene products, Bcl-2 and Bax regulate the apoptotic response by inhibiting and promoting cell death, respectively. The present study was performed to examine the age-related alertation of expression of Bcl-2 and Bax along with apoptosis in rat tibialis anterior muscles following ischemia-reperfusion. 9 weeks, 30 weeks and more than 65 weeks old male Sprague-Dawley rats were divided into 2 groups such as controls, 4 hour ischemia. 4 hour ischemia group was divided into 3 subgroups based on reperfusion time. For ischemia, left commom iliac artery was occulded for 4 hours. The tibialis anterior muscles were removed 0, 3, and 24 hours after onset of reperfusion. Muscle samples were embeded in paraffin and 6 micrometer sections were made. The expression level of Bcl-2 and Bax were examed using immunohistochemical methods and apoptotic reactions was detected using TUNEL methods. The results obtained were as follows; 1. In control group, Bcl-2 and Bax were weakly immunostained in 9 weeks old rat tibialis anterior muscles. In 30 and 65 weeks old rat tibialis anterior muscles, Bcl-2 immunostaning was minimal. The level of Bax staining was increased in 30 and 65 weeks old rat tibialis anterior muscles, compared with those of 9 weeks old rats. The level of apopto-sis among different age groups were not altered. 2. In the 4 hour ischemia group, the level of Bax staining was correlated with the level of apoptosis in 9 weeks, 30 weeks and 65 weeks old rat tibialis anterior muscles. 3. The level of apoptosis was increased in older groups relative to younger groups in 4 hour ischemia. These results suggested that the level of apoptosis induced by ischemic-reperfusion in tibialis anterior muscle increase with ageing in rat tibialis anterior muscles, and that a increase of Bax expression is related to increased apoptosis.
Animals
;
Apoptosis*
;
Cell Death
;
Humans
;
Iliac Artery
;
In Situ Nick-End Labeling
;
Ischemia
;
Male
;
Muscle, Skeletal
;
Muscles*
;
Paraffin
;
Rats*
;
Rats, Sprague-Dawley
;
Reperfusion
6.Finite element stress analysis of implant prosthesis according to connection types of implant-abutment.
Jin Kyung HUR ; Kee Sung KAY ; Chae Heon CHUNG
The Journal of Korean Academy of Prosthodontics 2005;43(4):544-561
PURPOSE: This study was to assess the loading distributing characteristics of implant systems with internal connection or external connection under vertical and inclined loading using finite element analysis. MATERIALS AND METHODS: Two finite element models were designed according to type of internal connection or external connection. The crown for mandibular first molar was made using cemented abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction (loading condition A), 200N at the centric cusp tip in a 15.inward inclined direction (loading condition B), or 200N at the centric cusp tip in a 30.outward inclined direction (loading condition C) respectively. Von Mises stresses were recorded and compared in the supporting bone, fixture, abutment and abutment screw. RESULTS: 1. In comparison with the whole stress of the model 1 and model 2, the stress pattern was shown through th contact of the abutment and the implant fixture in the model 1, while the stress pattern was shown through the abutment screw mainly in the model 2. 2. Without regard to the loading condition, greater stress was taken at the cortical bone, and lower stress was taken at the cancellous bone. The stress taken at the cortical bone was greater at the model 1 than at the model 2, but the stress taken at the cortical bone was much less than the stress taken at the abutment, the implant fixture, and the abutment screw in case of both model 1 and model 2. 3. Without regard to the loading condition, the stress pattern of the abutment was greater at the model 1 than at the model 2. 4. In comparison with the stress distribution of model 1 and model 2, the maximum stress was taken at the abutment in the model 1, while the maximum stress was taken at the abutment screw in the model 2. 5. The magnitude of the maximum stress taken at the supporting bone, the implant fixture, the abutment, and the abutment screw was greater in the order of loading condition A, B and C. CONCLUSION: The stress distribution pattern of the internal connection system was mostly distributed widely to the lower part along the inner surface of the implant fixture contacting the abutment core through its contact portion because of the intimate contact of the abutment and the implant fixture, and so the less stress was taken at the abutment screw, while the abutment screw can be the weakest portion clinically because the greater stress was taken at the abutment screw in case of the external connection system, and therefore the further clinical study about this problem is needed.
Crowns
;
Finite Element Analysis
;
Molar
;
Prostheses and Implants*
7.Pheochromocytoma with Unusual Electrocardiographic Changes and Having Clinical Features of Angina Pectoris : A Case Report.
Ki Hyun BAIK ; Dong Heon KANG ; Ki Bae SEUNG ; Seok Chan KIM ; Sang Woo KIM ; Yoon Kie MOON ; Eung Hun IM ; Jang Sung CHAE ; Jae Hyung KIM ; Soon Jo HONG ; Kyu Bo CHOI
Korean Circulation Journal 1995;25(5):1029-1035
A 50 year old female presented unusual electrocardiographic changes including AV block, accelerated idioventricular rhythm, ventricular premature systole with severe fluctuation of blood pressure and clinical features of angina pectoris. Deep ST segment depression was demonstrated in spite of the normal coronary arteriogram and the negative coronary artery spasm study. Urinary excretion of catecholamines and their metabolites were elevated and a huge pheochromocytoma was found in the left adrenal glandd. After removal of the pheochromocytoma, the electrocardiographic abnormalities and the blood pressure were normalized and teh aptient became asymptomatic.
Accelerated Idioventricular Rhythm
;
Angina Pectoris*
;
Arrhythmias, Cardiac
;
Atrioventricular Block
;
Blood Pressure
;
Catecholamines
;
Coronary Vessels
;
Depression
;
Electrocardiography*
;
Female
;
Humans
;
Middle Aged
;
Pheochromocytoma*
;
Spasm
;
Systole
8.A Case of Urosepsis Caused by Aerococcus viridans.
Jin Sung JUNG ; Se Heon CHANG ; Seung Hyen YOO ; Nam Ho KOO ; Yong Won PARK ; Mi Ju CHEON ; Yun Tae CHAE
Korean Journal of Medicine 2014;87(2):234-239
Aerococcus viridans is a rare pathogen in humans, with only six cases of A. viridans urinary tract infections reported worldwide. Nosocomial urinary tract infections with bacteremia caused by A. viridians are even rarer, with no prior reports of urosepsis caused by A. viridans occurring in the Republic of Korea. Here we report a case of urosepsis caused by A. viridans in a 79 year-old female nursing home resident. The patient was admitted to the hospital presenting a fever of 39degrees C, chills, and oliguria for two days prior to admission. Urine culture yielded a robust growth of 105 CFU/mL of A. viridians, with blood culture positive for the same organism. Following diagnosis, the patient was treated with ciprofloxacin intravenously for 2 weeks, resulting in clearance of the infection and a full recovery from urosepsis. Although A. viridans is rarely associated with human infections, this case shows that, under the right conditions, it can be responsible for severe infections like urosepsis.
Aerococcus*
;
Bacteremia
;
Chills
;
Ciprofloxacin
;
Diagnosis
;
Female
;
Fever
;
Humans
;
Nursing Homes
;
Oliguria
;
Republic of Korea
;
Urinary Tract Infections
9.Effects of Genetic Polymorphisms of Ethanol-Metabolizing Enzymes on Alcohol Drinking Behaviors.
Joo Young KEE ; Min Ok KIM ; Il Young YOU ; Ji Young CHAI ; Eui Sil HONG ; Sung Chul AN ; Heon KIM ; Seon Mee PARK ; Sei Jin YOUN ; Hee Bok CHAE
The Korean Journal of Hepatology 2003;9(2):89-97
BACKGROUND/AIMS: Genetic variations of ethanol-metabolizing enzymes can affect alcohol drinking behavior. The aims of this study were to investigate and compare the distributions of these genetic polymorphisms between a healthy control group and a heavy drinker group which included an alcoholic liver cirrhosis group. METHODS: Genotypes of ADH2, ALDH2, CYP2E1, and catalase were identified by polymerase chain reaction and restriction fragment length polymorphism. Genomic DNA was extracted from peripheral leukocytes in 42 healthy controls, 12 heavy drinkers, and 30 alcoholic liver cirrhosis patients. RESULTS: 1) The genotype frequencies of ALDH2 (1*1), ADH2 (1*1), CYP2E1 (c1c1), and catalase1 (TT) were 69%, 55%, 38%, and 12%, respectively in healthy Korean males. 2) There was a significant difference in the distribution of the genetic polymorphism of ALDH2 between the control group and heavy drinker group (12 heavy drinkers and 30 alcoholic liver cirrhosis patients). The genotype frequency of ALDH2 mutant, ALDH2 (1*2) and ALDH2 (2*2) in the heavy drinker group (12%) was significantly lower than that in the control group (30%). 3) We didn't find anyone with ALDH2 homozygote mutant (DD) in the heavy drinker group. 4) There was no significant difference in the distribution of genetic polymorphisms in ADH2, CYP2E1 and catalase1 between the two groups. CONCLUSIONS: These results suggest that the absence of ALDH2 mutant genotype is strongly related to heavy drinking behavior. We can not prove, however, any evidence that the polymorphisms of other ethanol-metabolizing enzymes are associated with the determination of alcohol-drinking behavior.
Adult
;
Alcohol Dehydrogenase/*genetics
;
Alcohol Drinking
;
Alcoholism/enzymology/*genetics
;
Aldehyde Dehydrogenase/*genetics
;
Cytochrome P-450 CYP2E1/*genetics
;
Ethanol/metabolism
;
Humans
;
Liver Cirrhosis, Alcoholic/enzymology/*genetics
;
Male
;
Middle Aged
;
*Polymorphism, Genetic
10.Relationship between Body Weight and Pulmonary Function in Pilots from a Airlines: The Comparison of Data from 1996 with 2002.
Young Dong SHIN ; Hwan Suk JUNG ; Kyung Chae KIM ; Ju Na LEE ; Noh Won PARK ; Won Keun LEE ; Je LEE ; Heon Kil LIM ; Jeong Hyun KIM
Korean Journal of Aerospace and Environmental Medicine 2003;13(3):136-143
BACKGROUND: Obesity increases the risk of cardiovascular disease, hypertension, diabetes, and other disorders. Several studies have shown that excess weight or weight gain was related to the decline of pulmonary function. This study is to find out whether pilot's age, height, body weight, body mass index(BMI) and smoking are related to the baseline measurement of pulmonary function in order to promote the healthy behavior of pilots. METHOD: The analysis was based on data from the annual physical examination of pilots which was conducted in one airlines company of Korea. This study compared the data obtained from 73 pilots in 1996 with the data in 2002. Pulmonary function(forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximal mid expiratory flow (MMEF), peak expiratory flow (PEF)), age, height, body weight and body mass index were measured in both surveys. Multivariate analysis of variance (MANOVA) was used to examine the relationship weight gain, smoking and pulmonary function. RESULTS: According to the data from 2002, mean age, mean height, mean body weight and mean BMI of pilots were examined: 47.62 years, 171.60 cm, 70.6 Kg and 24.03 Kg/m(2). Age was significantly related to FVC, FEV1 and MMEF. Height was significantly related to FVC and FEV1. However, body weight was significantly related to PEF and MMEF. The effect of smoking on pulmonary function was not significant. Pilots who gained body weight and BMI after 7 years were not related significantly to the pulmonary function. CONCLUSION: This study shows that age, height, weight are significantly related to pulmonary function. And other studies show that weight gain is significantly related to the decline of pulmonary function, but the relationship from this study is not significant because the number of sample is not enough and healthy behaviors of most pilots are relatively well.
Body Height
;
Body Mass Index
;
Body Weight*
;
Cardiovascular Diseases
;
Forced Expiratory Volume
;
Hypertension
;
Korea
;
Multivariate Analysis
;
Obesity
;
Physical Examination
;
Smoke
;
Smoking
;
Vital Capacity
;
Weight Gain