1.THREE-DIMENSIONAL COMPARISON OF FRAMEWORK DISPLACEMENTS JOINED BY VARIOUS CONNECTION TECHNIQUES.
Jang Seop LIM ; Young Chan JEON ; Chang Mo JEONG
The Journal of Korean Academy of Prosthodontics 1999;37(3):358-374
This study measured the relative displacements of the five-unit fixed partial dentures as cast with the same fixed partial dentures sectioned and assembled by investment-soldering, soldering stand-soldering, and cast-joining techniques. A total of fifteen specimens using a type IV gold alloy wee one-piece cast as control and then sectioned and assembled five test specimens for each method were prepared. A computerized three dimensional coordinate measuring machine and specially designed cylinder for this study were used. Displacement was defined by six displacement variables for the each of cylinders incorporated in each casting: three component displacements ( Lx, Ly, and Lz) and rotational displacements( thetax, thetay, thetaz). The global displacement was computed using the mathematical formula R= Global displacement ={{{{rm SQRT { (x'-x)^2 +(y'-y)^2 + (z'-z)^2} }} }} Under the conditions of this study, the following conclusions were drawn: 1. The investment-soldering group showed the largest mean value of final global displacements, followed by stand-soldering group, cast-joining group and one-piece cast group. However, between the mean values of final global displacement for the cast-joining group and one-piece cast group, there was no significant difference. 2. For investment-soldering and stand-soldering groups, the greater global displacements were recorded in soldering phase than in indexing or investing phase. 3. For one-piece cast group, the displacements occured mostly in the casting phase. And for castjoining group, there was no significant difference in global displacements among the fabrication procedures. 4. Intercentroidal distance decreased in framework-pattering, solder-indexing, solder-standing, and soldering phases, but increased in investment block-investing and casting phases. 5. Specially designed cylinder for touch-trigger type coordinate measuring machine was validated.
Abstracting and Indexing as Topic
;
Alloys
;
Denture, Partial, Fixed
;
Investments
;
Methods
2.A MEASUREMENT OF DISPLACEMENTS OF CAST FRAMEWORK BY TORCH SOLDERING AND ELECTRIC SOLDERING TECHNIQUES.
Sang Won JEON ; Jang Seop LIM ; Chang Mo JEONG ; Young Chan JEON
The Journal of Korean Academy of Prosthodontics 1999;37(6):791-799
The purpose of this study was to investigate the displacements of cast framework by torch soldering and electric soldering techniques. Specimen had two cylinders and connecting bar that had sectioned with 0.3mm gap at mid point. 10 of total specimens were divided into two groups. In torch soldered group, soldering investment block was made and conventional torch soldering procedure was carried out. In electric soldered group, electric soldering was carried out on the master cast without soldering investment block by using electric soldering machine(Dentapunkt DP 7, Kulzer, Germany). After soldering procedure, three dimensional coordinates of two centroids of each cylinder were measured by three dimensional coordinate measuring machine. The intercentroidal displacement and global displacement were calculated and then, these values were compared and evaluated. The results were obtained as follows: 1. Intercentroidal distances of specimens decreased after both soldering procedures, and the decrease in intercentroidal distance was greater for torch soldered group than for electric soldered group 2. Global displacements of torch soldered group were greater than those of electric soldered group
Investments
3.Femoral Neck Fracture in Young Adult: 25 Cases Treated with Multiple Pinning
Hyung Ku YOON ; Kwang Pyo JEON ; Dae Eun JUNG ; Ho Seung JEON ; Dae Young JANG
The Journal of the Korean Orthopaedic Association 1996;31(2):235-246
In general. femoral neck fracture in young adult presents poor prognosis due to the high velocity injury, high angle shear fracture, and poor candidate for arthroplasty. In addition to the relative rarity of the injury, the high incidence of aseptic necrosis and nonunion have been reported in the management of these fractures. 25 cases of femoral neck fracture in young adult were treated with multiple pinning and analyzed at Sung-Ae general hospital from 1987 to 1994 after 28 months follow up in average with review of charts, X-ray and clinical result. There were 18 male and 7 female, 5 cases of them had significant polytrauma to other organs or skeletal system, authors tried to treat them as soon as possible to decrease the interval time between fracture and fixation (the average time was 39.7 hours.) Union occurred in all of Garden stage I (4 cases) and II (4 cases), but in Garden stage III (7 among 8 cases) and IV (7 among 9 cases) the union rate was lower. Average union time was 16.5 weeks. The incidence of complications (12%, 3 among 25 cases) was higher in displaced fractures group (Garden stage III, IV) and also in poorly reduced group of Garden’s alignment index. In conclusion, the prognosis of femoral neck fractures in young adult was related with mainly initial reduction and rigid fixation than the initial injury.
Agriculture
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Arthroplasty
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Female
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Femoral Neck Fractures
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Femur Neck
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Follow-Up Studies
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Hospitals, General
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Humans
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Incidence
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Male
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Multiple Trauma
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Necrosis
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Prognosis
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Young Adult
4.Histological Study of Ductus Arteriosus Affected by Indomethacin in the Fetal Rates.
Young Sook JANG ; Chang Yeoul JEON ; Heon Sook LEE ; Jung Soo KIM ; Moo Sam LEE
Journal of the Korean Pediatric Society 1983;26(8):770-777
No abstract available.
Ductus Arteriosus*
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Indomethacin*
5.Comparison Study of Lesion Localization in Patients with Primary and Secondary Hyperparathyroidism using Double-Phase Tc-99m Sestamibi Scintigraphy.
Tae Joo JEON ; Jong Doo LEE ; Young Hoon RYU ; Jung Soo PARK ; Hang Seok JANG
Korean Journal of Nuclear Medicine 1999;33(4):368-380
PURPOSE: The purpose of this study was to evaluate and compare the scintigraphic findings and diagnostic accuracy of double-phase Tc-99m sestamibi scan in primary and secondary hyperparathyroidism (HPT). MATERIALS AND METHODS: We retrospectively reviewed 16 cases of primary (18 lesions) and 11 cases of secondary HPT (44 lesions) who underwent Tc-99m-sestamibi scan before the surgical intervention. Scan was performed using LEM camera (Siemens, Germany) after the injection of 740MBq of Tc-99m sestamibi. Routine image consisted of baseline and 3-hour delayed images and each image was obtained using both parallel and pine hole collimator. The study population was 27 patients (male/female=5/22, age: 49.1+/-10.8). RESULTS: Eighteen lesions of primary HPT consisted of 13 adenomas and 5 hyperplasias, while all lesions of secondary HPT were hyperplasias. Among the case of primary HPT, we could detect all the lesions of 13 adenomas but only 2 lesions of 5 hyperplasias (40%) could be detected by double phase scintigraphy. Three cases of primary lesion showed decreased uptake in delayed images compared with baseline. The sensitivity, specificity, positive predictive value and accuracy of primary and secondary HPT were 58.8% (10/17), 83.3% (10/12), 83.3% (10/12), 75.9% (22/29), and 37.5% (15/40), 50% (2/4), 88.2% (15/17), 38.6% (17/44), respectively. Overall sensitivity, specificity, positive predictive value and accuracy were 43.9% (25/57), 75% (12/16), 86.2% (25/29), and 53.4% (39/73). There were no statistical difference between the weight of primary and secondary HPT lesion (p>0.05). CONCLUSION: Tc-99m sestamibi scan is fairly good modality to detect parathyroid lesion in patient with primary HPT before the surgical intervention. However, since some of cases may reveal decreased uptake in delayed image, a careful attention to the findings of baseline images may be helpful. Still the low accuracy of sestamibi scan in diagnosis of secondary HPT prohibits routine use of it for this disease.
Adenoma
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Diagnosis
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Humans
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Hyperparathyroidism, Primary
;
Hyperparathyroidism, Secondary*
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Hyperplasia
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Parathyroid Glands
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Radionuclide Imaging*
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Retrospective Studies
;
Sensitivity and Specificity
6.Effect of Degassing Condition on Ceramic Bond Strength of Ni-Cr Alloys.
Eun Hwa LEE ; Young Chan JEON ; Chang Mo JEONG ; Jang Seop LIM
The Journal of Korean Academy of Prosthodontics 2000;38(4):461-471
This study evaluated the effect of dagassing on the ceramic bond strength of two Ni-Cr alloys under varying holding time at the upper limit temperature and atmospheric conditions. Metal specimens were divided into 5 groups for each alloy according to degassing conditions prior to porcelain application : no degassing, degassing under vacuum without hold, degassing under vacuum with hold for 5min. and 10 min. respectively at the upper limit temperature and degassing in air. Total number of metal ceramic specimens was eighty and each group had eight specimens : The ceramic bond strength was measured by four-point flexural test using Instron and the fractured surface was examined under SEM. The results obtained were as follows. 1. Degassing in air improved the ceramic bond strength of Ni-Cr alloys. 2. in degassing under vacuum, hold at the upper limit temperature was advantageous to the ceramic bonding of Ni-Cr alloys. 3. After ceramic metal bond test, metal surfaces were partially covered with the thin porcelain layer, and the cohesive failures in porcelain were predominant in groups showing higher ceramic bond strength.
Alloys*
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Ceramics*
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Dental Porcelain
;
Vacuum
7.THE INFLUENCE OF WATTAGE AND CURING TIME OF MICROWAVE ENERGY ON PHYSICAL PROPERTIES OF THE DENTURE BASE RESIN.
Dae Sung JEONG ; Jang Seop LIM ; Chang Mo JEONG ; Young Chan JEON
The Journal of Korean Academy of Prosthodontics 1999;37(6):767-775
The purpose of this study was to evaluate the effect of wattage and curing time on surface hardness, three-point bending strength and internal porosity of microwave curing denture base resin. Two sizes of resin spicimens were made of Acron MC ; 3.5x10x60mm for surface hardness and three-point bending strength measurement and 5x12x60mm for internal porosity measurement. They were cured by microwave energy at varing wattages(500W, 700W) and curing times(2min., 3min., 4min.) to determine if a certain wattage/curing time combination would improve physical properties. Surface hardness was measured with Vikers hardness tester, three-point bend-ing strength with universal testing machine and internal porosity was calculated by measuring the weight in air and in water. The results obtained were as follows : 1. There was no significant difference in percent porosity among experimental groups(p>0.05). 2. 500W/3min, group showed the higher surface hardness than 700W/2, 3, 4min. groups(p<0.05), and 700W/4 min. group showed the lower surface hardness than 500W/2, 3, 4min. groups(p<0.05), but there was no significant difference among others(p>0.05). 3. 500W/3min. group yielded the higher value of bending strength than 500W/2min., 700W/3, 4min. groups(p<0.05), but there was no significant difference among others(p>0.05).
Denture Bases*
;
Dentures*
;
Hardness
;
Hardness Tests
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Microwaves*
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Polymethyl Methacrylate
;
Porosity
;
Water
8.A STUDY FOR SETTING AND THERMAL EXPANSION OF DENTAL SOLDERING INVESTMENTS.
Sung Ae SHIN ; Jang Seop LIM ; Chang Mo JEONG ; Young Chan JEON
The Journal of Korean Academy of Prosthodontics 1999;37(6):730-740
The purpose of this study was to investigate setting and thermal expansion of dental soldering investments. In order to compare expansion rates and to investigate the effect of water/powder ratio on expansion, setting and thermal expansion of four dental soldering investments were measured under three different water/powder ratio conditions: standard, 20% decreased and 20% increased. Setting expansion of investments was measured by use of dialgauge method. Each measurement was started two minutes later from the beginning of spatulation and recorded every one minute for one hour. Thermal expansion of cylindrical test specimens, 10mm diameter, 50mm length, was recorded in a Thermodilatometer at heating rate of 10degrees C per minute from 25degrees C to 700degrees C. The results of this study were obtained as follows: 1. Setting expansion rates under the standard water/power ratio condition were 0.198% in Speed-E, 0.090% in Deguvest, 0.080% in CM and Hi-temp. Setting expansion of Speed-E was significantly different from those of CM, Deguvest and Hi-temp, and setting expansion of Deguvest was significantly different from those of CM and Hi-temp(p<.05). 2. Under the decreased water/powder ratio condition, there was significant increase in setting expansion of 4 dental soldering investments(p<.05). 3. There were no significant differences in setting expansions of investments except Hi-temp between standard and increased water/powder ratio condition(p<.05). 4. Thermal expansion rates under the standard water/powder ratio condition were 1.923% in Deguvest, 1.629% in Speed-E, 1.619% in Hi-temp and 1.580% in CM. No significant difference in thermal expansions under the standard water/powder ratio condition existed only between Speed-E and Hi-temp(p<.05). 5. Under the decreased water/powder ratio condition, there was significant increase in thermal expansion of CM and Deguvest but decrease in thermal expansion of Speed-E(p<.05). 6. Under the increased water/powder ratio condition, there was significant decrease in thermal expansion of CM, Deguvest and Speed-E but decrease in thermal expansion of Hi-temp(p<.05).
Dental Soldering*
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Heating
;
Hot Temperature
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Investments*
9.COLORIMETRIC ANALYSIS OF COLOR DIFFERENCES BETWEEN DENTIN PORCELAINS.
Chang Seop KIM ; Jang Seop LIM ; Chang Mo JEONG ; Young Chan JEON
The Journal of Korean Academy of Prosthodontics 1999;37(4):425-432
The purpose of this study is to evaluate the color differences that can exist between differnet brands of dentin porcelain having identical shade designations. The instrumental colorimetric technique was used to determine these differences. The three brands of dentin porcelain used were Vita VMK-68, Shofu Vintage, and Ceramco II. The three shades selected were the Vita Lumin shades A2, B2, and C2. The color difference values were compared with each other using L*, a*, b*, three variables of the CIELAB color system, and E. The results of this study were as follows: 1. Corresponding shades of different brands of dentin porcelain produced different L*, a*, b* values. 2. The greatest E value in corresponding shade was found to exist between Ceramco II and Shofu Vintage, followed by between Vita VMK-68 and Ceramco II, and then between Vita VMK-68 and Shofu Vintage. 3. The E values in shade C2 were mainly influenced by L* value ; however none of L*, a*, b* values had greater influence on E values than the others in shade A2, B2. 4. Shofu Vintage had the highest b* value, followed by Vita VMK-68, and then Ceramco II.
Dental Porcelain*
;
Dentin*
10.Factors Affecting Body Image Discordance Amongst Korean Adults Aged 19–39 Years.
Hye Young JANG ; Jung Won AHN ; Mi Kyeong JEON
Osong Public Health and Research Perspectives 2018;9(4):197-206
OBJECTIVES: This study was designed to investigate factors affecting the discordance between body image and body mass index amongst Korean adults aged 19–39 years. METHODS: Data (N = 59,361) from the 2014 Korean Community Health Survey was analyzed using descriptive analysis, chi-square test, and logistic regression analysis. RESULTS: To examine the factors affecting body image discordance as observed in 43.1% of participants, the group was subdivided into underestimation and overestimation. There were 36.0% of participants that were body image discordant underestimators and 7.1% were overestimators. Multivariate logistic regression analysis showed that the underestimators tended to be men, graduated from high school, married, current/ex-smokers, ex-drinkers, had between 5 to 9 hours sleep (inclusive), had fair to good self-rated health, and demonstrated healthy weight control behavior, relative to the reference group. In comparison, overestimators tended to be in the 19–29 year group and had signs of depression. The OR of individuals who were men, married, and had healthy weight control behavior was significantly lower in the overestimators group. CONCLUSION: These findings show that tailored interventions to promote accurate body awareness should be based on the type of body image discordance. In addition, it is necessary to develop and implement a program of body image improvement that considers the factors affecting body weight discordance.
Adult*
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Body Image*
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Body Mass Index
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Body Weight
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Depression
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Health Surveys
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Humans
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Logistic Models
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Male
;
Overweight