1.STRAIN AND TEMPERATURE CHANGES DURING THE POLYMERIZATION OF AUTOPOLYMERIZING ACRYLIC RESINS.
Hyung Jun AHN ; Chang Whe KIM ; Yung Soo KIM
The Journal of Korean Academy of Prosthodontics 2001;39(6):709-734
The aims of this experiment were to investigate the strain and temperature changes simultaneously within autopolymerizing acrylic resin specimens. A computerized data acquisition system with an electrical resistance strain gauge and a thermocouple was used over time periods up to 180 minutes. The overall strain kinetics, the effects of stress relaxation and additional heat supply during the polymerization were evaluated. Stone mold replicas with an inner butt-joint rectangular cavity (40.0x25.0mm, 5.0mm in depth) were duplicated from a brass master mold. A strain gauge (AE-11-S50N-120-EC, CAS Inc., Korea) and a thermocouple were installed within the cavity, which had been connected to a personal computer and a precision signal conditioning amplifier (DA 1600 Dynamic Strain Amplifier, CAS Inc., Korea) so that real-time recordings of both polymerization-induced strain and temperature changes were performed. After each of fresh resin mixture was poured into the mold replica, data recording was done up to 180 minutes with three-second interval. Each of two poly (methyl methacrylate) products (Duralay, Vertex) and a vinyl ethyl methacrylate product (Snap) was examined repeatedly ten times. Additionally, removal procedures were done after 15, 30 and 60 minutes from the start of mixing to evaluate the effect of stress relaxation after deflasking. Six specimens for each of nine conditions were examined. After removal from the mold, the specimen continued benchcuring up to 180 minutes. Using a waterbath (Hanau Junior Curing Unit, Model No.76-0, Teledyne Hanau, New York, U.S.A.) with its temperature control maintained at 50degrees C, heat-soaking procedures with two different durations (15 and 45 minutes) were done to evaluate the effect of additional heat supply on the strain and temperature changes within the specimen during the polymerization. Five specimens for each of six conditions were examined. Within the parameters of this study the following results were drawn : 1. The mean shrinkage strains reached -3095mu epsilon, -1796mu epsilon and -2959mu epsilon for Duralay, Snap and Vertex, respectively. The mean maximum temperature rise reached 56.7degrees C, 41.3degrees C and 56.1degrees C for Duralay, Snap, and Vertex, respectively. A vinyl ethyl methacrylate product (Snap) showed significantly less polymerization shrinkage strain (p<0.01) and significantly lower maximum temperature rise (p<0.01) than the other two poly (methyl methacrylate) products (Duralay, Vertex). 2. Mean maximum shrinkage rate for each resin was calculated to ?31.8mu epsilon/sec, -15.9mu epsilon/sec and ?31.8mu epsilon/sec for Duralay, Snap and Vertex, respectively. Snap showed significantly lower maximum shrinkage rate than Duralay and Vertex (p<0.01). 3. from the second experiment, some expansion was observed immediately after removal of specimen from the mold, and the amount of expansion increased as the removal time was delayed. For each removal time, Snap showed significantly less strain changes than the other two poly (methyl methacrylate) products (p<0.05). 4. During the external heat supply for the resins, higher maximum temperature rises were found. Meanwhile, the maximum shrinkage rates were not different from those of room temperature polymerizations. 5. From the third experiment, the external heat supply for the resins during polymerization could temporarily decrease or even reverse shrinkage strains of each material. But, shrinkage re-occurred in the linear nature after completion of heat supply. 6. Linear thermal expansion coefficients obtained from the end of heat supply continuing for an additional 5 minutes, showed that Snap exhibited significantly lower values than the other two poly (methyl methacrylate) products (p<0.01). Moreover, little difference was found between the mean linear thermal expansion coefficients obtained from two different heating durations (p>0.05).
Acrylic Resins*
;
Electric Impedance
;
Fungi
;
Heating
;
Hot Temperature
;
Kinetics
;
Microcomputers
;
Polymerization*
;
Polymers*
;
Relaxation
2.Internal Fixation Using Clavicle Hook Plates for Distal Clavicle Fractures.
Kwang Yul KIM ; Hyung Chun KIM ; Sung Jun CHO ; Su Han AHN ; Dong Seon KIM
Clinics in Shoulder and Elbow 2015;18(1):21-27
BACKGROUND: To report the radiological and clinical outcomes of internal fixation using distal clavicle hook plates for distal clavicle fractures. METHODS: From April 2008 to December 2012, 32 patients with distal clavicle fractures underwent surgery using an AO hook plate. The reduction was qualified and evaluated according to the radiological findings. The evaluation of the clinical outcomes was performed with the University of California at Los Angeles (UCLA) score, the Korean Shoulder score, and the visual analogue scale (VAS) pain score. RESULTS: By radiological evaluation, we found that 31 of 32 patients showed anatomical reduction and solid bone union. Although we obtained satisfactory UCLA scores, Korean Shoulder Scale scores, and VAS pain scores, 12 cases of complications were present. We found 4 cases of osteolysis of the acromion, 1 case of nonunion, 3 cases of periprosthetic fractures, 3 cases of subacromial pain, and 1 case of skin irritation. We performed re-operations in 2 patients. CONCLUSIONS: To avoid complications associated with clavicle hook plates, choosing the appropriate hook size and bending of the hook according to the slope of the acromion undersurface is critical. Also, we believe that early removal of clavicle plates may help reduce complications.
Acromion
;
California
;
Clavicle*
;
Humans
;
Osteolysis
;
Periprosthetic Fractures
;
Shoulder
;
Skin
3.A case of congenital goiter with congenital hypothyroidism due to organification defect.
Ik Hee LEE ; Sung Yong JUNG ; Thi Hyung PARK ; Sa Jun CHUNG ; Chang Il AHN
Journal of the Korean Pediatric Society 1993;36(7):1002-1008
We experienced a case of congenital goiter with congenital hypothyroidism in 45 day-old male, who complained of respiratory difficulty and anterior neck mass. After admission, he was diagnosed congenital hypothyroidism by the clinical manifestations and laboratory tests including biochemistry, radioimmunoassay, radioisotope study, perchlorate discharge test, and bone radiography. We obtained positive finding at the perchlorate discharge test and found that his congenital goiter with congenital hypothyroidism was manifested by organification defect. We started treatment with L-thyroxine orally at 6th hospital day. The case was presented with brief review of literatures.
Biochemistry
;
Congenital Hypothyroidism*
;
Goiter*
;
Humans
;
Male
;
Neck
;
Radiography
;
Radioimmunoassay
;
Thyroxine
4.A FLUOROSCOPIC STUDY ON THE STABILITY OF SKIN REFERENCE POINTS DURING JAW OPENING AND CLOSING MOVEMENT.
Hyung Jun AHN ; Chang Whe KIM ; Yung Soo KIM ; Yong Ho KIM
The Journal of Korean Academy of Prosthodontics 1999;37(4):516-530
The current clinical technique for occlusal vertical dimension recording is based on marking the skin reference points on the patient's face and measuring between these pints using caliper-like device. And it is difficult to achieve reliable measurements by this technique because of movable soft tissue. The purpose of this study is to reveal the stability of skin reference points by comparing the relative movement between extra-oral skin reference points and intra-oral reference points using X-ray fluoroscope. 10 test subjects were divided into 2 groups : Group I (natural dentition) and Group II (denture-wearer whose vertical dimension was lost) and Group III consists of identical test subjects to Group II with their upper denture removed and record base inserted. Attaching the 3mm diameter steel ball to nose tip, chin and to existing denture (or record base), fluoroscopic examination and recording were taken during 2 jaw opening and closing movements. After subsequent digitization using personal compute, 1219 still pictures with 0.1 second interval were made. Using the 2 dimensional graphic software, measurements between reference points were executed. Dividing the entire jaw movement into 3 ranges (total, 1st half opening, 2nd half opening), rate of movement and relative movement between extra-oral and intra-oral reference points were calculated and statistically analyzed. The results of this study are as follows. 1. Within the same experimental group, no statistical difference was found in the stability of skin reference between lower lip point and chin point during total range of jaw opening and closing movement (p>.05). 2. In the first half range of jaw opening, statistical difference was found between Group I (natural dentition) and Group II (denture wearer) (p<.05). Group I has greater skin reference stability than Group II. 3. In the first half range of jaw opening, statistical difference was found between Group I and Group III (record base wearer) (p<.05). Group I has greater skin reference stability than Group III. 4. In the first half range of jaw opening, no statistical difference was found in the stability of skin reference between Group II and Group III (p>.05). 5. In the second half range of jaw opening, no statistical difference was found in the stability of skin reference between any experimental groups (p>.05). 6. In patients with their occlusal vertical dimension lost, employing other measuring references rather than skin is recommended because of low stability.
Chin
;
Dentures
;
Humans
;
Jaw*
;
Lip
;
Nose
;
Skin*
;
Steel
;
Vertical Dimension
5.TISSUE EXPANSION FOR HAIR REPLACEMENT SURGERY AND TREATMENT OF MALE PATTERN BALDNESS.
Hyung Jun KIM ; Sang Hwan KOO ; Duk Sun AHN ; Byung Kyu SOHN
Journal of the Korean Society of Plastic and Reconstructive Surgeons 1997;24(4):839-846
No abstract available.
Alopecia*
;
Hair*
;
Humans
;
Male*
;
Tissue Expansion*
6.Diagnostic accuracy of stable microbubble rating test for the early detection of neonatal respiratory distress syndrome.
Jung Sam JUN ; Chy Hyung PARK ; Jong Woo BAE ; Chang Il AHN
Journal of the Korean Pediatric Society 1992;35(10):1361-1368
No abstract available.
Microbubbles*
;
Respiratory Distress Syndrome, Newborn*
7.A Clinicopathologic Study of 31 Cases with Ovarian Malignant Germ Cell Tumors.
Nam Won SEO ; Cheon Jun LEE ; Do Hyung KIM ; Un Mo AHN ; Tae Hong YEO ; Jun Houg KIM ; Sunn Ie AHN ; Dong Hwi KIM ; Un Dong PARK
Korean Journal of Obstetrics and Gynecology 2000;43(1):51-57
OBJECTIVE: The purpose of this study was to review the clinicopathologic features, recurrent rate, survival rate and controversable issues in the treatment of the ovarian malignant germ cell tumors. PATIENTS AND METHODS: From August, 1991 to November, 1998 thirty-one patients with malignant germ cell tumors of the ovary treated in the department of obstetrics and gynecology, Kosin University Medical college, were eligible and assessable. Demographic characteristics, symptoms, signs, stage, tumor grade, mode of therapy and results of follow up were reviewed retrospectively. RESULTS: The patients with malignant germ cell tumor constituted 6.37% of all ovarian malignancies during this period. Histologic subtypes were 8 dysgerminoma(25.8%), 7 endodermal sinus tumor(22.6%), 10 immature teratoma(32.3%), 3 mixed germ cell tumor(9.7%), 3 choriocarcinoma(9.7%). The age of the patients ranged from 10 to 40 years (mean +/-S.D.; 24.26 +/- 7.51). The most common symptom was abdominal pain(38.7%). Most had stageI(18 cases, 58.0%) or stageIII(5 cases, 16.2%) diseases. All patients underwent surgery as the initial treatment, and nine patients received more than one operation. Postoperative adjuvant chemotherapeutic regimens were VAC, VBP, EP, BEP, EMA, and EMA CO. The mean follow up duration was 26.0(+/- S.D.; +/- 20.3) months. The 2-year and 5-year survival rate were 91.97%(+/- S.E.; +/- 0.05) and 86.86%(+/- S.E.; +/- 0.07).
Endoderm
;
Female
;
Follow-Up Studies
;
Germ Cells*
;
Gynecology
;
Humans
;
Neoplasms, Germ Cell and Embryonal*
;
Obstetrics
;
Ovary
;
Retrospective Studies
;
Survival Rate
8.Prevention of Septal Perforation During Septal Surgery Using Inferior Turbinate Mucosa and Fibrin Glue.
Bo Hyung KIM ; Sung Ho KANG ; Jeong Yoon AHN ; Seok Chan CHOI ; Hyung Jun LEE ; Dae Jun LIM
Journal of Rhinology 2009;16(2):143-147
BACKGROUND AND OBJECTIVES: As septal surgery is being performed more and more often, the incidence of septal perforation as a complication arising from the surgery has also increased. In septal surgery, if corresponding mucoperichondrial tears occurred on both sides, autologous cartilage is usually placed between the injured mucopercondrium. However, septal perforation is sometimes found after septal surgery even after this effort. The aims of this study were to introduce a new technique for the prevention of septal perforation during septal surgery using inferior turbinate mucosa and fibrin glue and to determine its usefullness by evaluating the treatment outcome. MATERIALS AND METHODS: Between June 2005 and May 2007, 358 cases of septal surgery were performed. Bilateral mucoperichondrial tears on corresponding areas occurred in 26 cases. In Group 1 (15 cases), autologous cartilage was inserted between injured mucoperichondrium. In Group 2 (11 cases), autologous cartilage was inserted and then was repaired using fibrin glue and inferior turbinate mucosa. The authors compared the perforation rate between the two groups. RESULTS: In Group 1, septal perforation occurred in 7 of 15 patients (46.7%) and in Group 2, 1 of 11 patients (9.0%) had perforation. Perforation rates were significantly lower in Group 2. CONCLUSION: The technique of using fibrin glue and inferior turbinate mucosa may be an easy, effective method for the prevention of septal perforation during septal surgery.
Cartilage
;
Fibrin
;
Fibrin Tissue Adhesive
;
Humans
;
Incidence
;
Mucous Membrane
;
Turbinates
9.Ultrastructure of the Experimentally Induced Cataract in Porcine Crystalline Lens.
Jung Hyub OH ; Sung Bum HONG ; Jin Hyung AHN ; Jun Suk TAE
Journal of the Korean Ophthalmological Society 1999;40(5):1210-1216
One of the purposes of this experiment is to observe the structure of crystalline lens with cataract, which is formed artificially, using the light microscope and electron microscope. The other is to observe the differences of structural variations in the cataract developed inside body. Twelve eyes of six pigs were used for this experiment. Two of them are normal crystalline lens, five are cystalline lens in distilled water, and the rest are in balanced salt solution through intact or ruptured capsule. We examined the time of cataract formation and compared the ultrastructural changes. Ruptured capsule and high osmotic pressure difference induced more rapid opacity. In case of distilled water, the capsule is maintained but it is very difficult to distinguish between epithelium and lens fibers. Also, there is a severe crack in the lens fibers. In electron microscopic, as the cataract progresses, the osmotic swelling becomes more prominent. One of the striking changes was a marked intercellular cyst formation. Lens cells became irregular in size and density and were extensively vacuolated. The swelling of the lens cells continuously induced large intracellular vacuoles and liquefied the cytoplasmic protein. In conclusion, the structural change of cataract, which was seen by an electron microscope, resulted from change in osmolarity from previously announced in vivo experiment and structural change resulted from this experiment are similar.
Cataract*
;
Crystallins*
;
Cytoplasm
;
Epithelium
;
Lens, Crystalline*
;
Microscopy, Electron
;
Osmolar Concentration
;
Osmotic Pressure
;
Strikes, Employee
;
Swine
;
Vacuoles
;
Water
10.Comparison of Two Surgeries in Active Thoracolumbar Tuberculous Spondylitis: One Stage Anterior Debridement with Anterior Instrumentation and Two Stage Operation of Anterior Debridement and Posterior Instrumentation.
Weon Wook PARK ; Seong Jun AHN ; Jung Sub LEE ; Tae Hyung KIM
Journal of Korean Society of Spine Surgery 2003;10(2):146-153
STUDY DESIGN: Thirty-eight patients with thoracolumbar spinal tuberculosis were evaluated according to the surgical treatment method, either a one or two stage anterior debridement, with anterior or posterior instrumentation, respectively. PURPOSE: The aim of this study was to compare the effects of the one stage anterior debridement, with anterior instrumentation, to the two stage anterior debridement, with posterior instrumentation MATERIALS AND METHODS: Thirty-eight patients, with tuberculous spine, were divided into two groups depending on the surgical method. One group consisted of 21 patients treated with anterior debridement combined with anterior instrumentation, and the other group consisted of 17 patients treated by a two stage operation of anterior debridement combined with posterior instrumentation. The clinical outcomes were evaluated from the hematological laboratory findings, bone union in radiographs, change of kyphotic angle, duration of hospital stay and the medical cost during hospitalization. RESULTS: There were no recurrences of infection in either group and bone union was obtained within 6 months of the operation for all cases in both groups. The preoperative, postoperative and final follow-up kyphotic angle in the two groups were 18/20, 7/9 and 10/11 degrees, respectively. There was no significant difference in the decrease of the kyphotic angle between the two groups (p>0.05). However, group I was superior to group II in relation to the duration of hospital stay and the medical cost. CONCLUSION: We concluded that the one stage operation was the better of the operative methods for the treatment of active tuberculous spondylitis in a thoracolumbar spine.
Debridement*
;
Follow-Up Studies
;
Hospitalization
;
Humans
;
Length of Stay
;
Recurrence
;
Spine
;
Spondylitis*
;
Tuberculosis, Spinal