1.ANALYSIS OF THE FIT IN THE IMPLANT PROSTHESIS USING LASER DISPLACEMENT METER AND THREE-DIMENSIONAL FINITE ELEMENT METHOD.
Ho Beom KWON ; Yung Soo KIM ; Chang Whe KIM
The Journal of Korean Academy of Prosthodontics 2001;39(6):611-624
A precise fit of the implant prosthesis is one of the most important factors in preventing mechanical complications. To analyze the degree of the misfit of implant prosthesis, a modal testing experiment was accomplished. And to interpret the modal testing analysis mathematically, three-dimensional finite element models were established. In the experimental modal testing analysis, with a laser displacement meter, FFT analyzer, impact hammer, etc., natural frequencies of the models with various degree of prosthesis fit were determined after the frequency response function were calculated. In the finite element analysis, the natural frequencies and mode shapes of the models which simulated those of experimental modal testing were computed. The results were as follows : 1. Natural frequencies of the prosthesis-abutment were related to the contact state between components. 2. In the modal testing experiment, the natural frequencies increased from 50micrometer to 200micrometer gap and reached a plateau. 3. In the finite element analysis, the natural frequencies decreased gradually according to the increase of the gap size. 4. In the finite element analysis, the mode shapes of model 1 with misfitting prosthesis showed different patterns from those without misfitting prosthesis. 5. The devices including a laser displacement meter used in this study were useful for measuring the natural frequencies of an implant prosthesis which had various degrees of fit.
Finite Element Analysis
;
Prostheses and Implants*
2.A Case of Muscle Transplantation in the Lateral Rectus Muscle Paralysis.
Yung Ho KWON ; Do Joon SONG ; Hyung Jean KIM
Journal of the Korean Ophthalmological Society 1969;10(2):23-26
Muscle transplanation surgery is presently widely accepted as a good precedure not only for cosmetic, but also for functional results, a concept to which Marina's observations on the absence of fixed and predetermined functions in the nuclei and associated tracts of the oculomotor system give great support; however, not everyone is in agreement with this concept. This paper report one case in which the total transplantation of the vertical rectus muscles midway between their insertions and the insertion of the lateral rectus muscle were carried out, in addition recession of the medial rectus muscle and resection of the paralyzed lateral rectus muscle. Our case have been followed up during 8 months to rule out late complications, aspecially ocular movement and diplopia. No late complications, however, have been found up to remaining underaction of the right superior and inferior oblique muscles and also medial rectus muscle. The eyes were straight with abduction of the right eye up to 40 prism diopters. Binocular vision was present and there was no diplopia. The cosmetic result was excellent.
Diplopia
;
Muscles
;
Paralysis*
;
Vision, Binocular
3.THE EFFECT OF AUTOLOGOUS PLATELET-RICH PLASMA (PRP) ON BONE FORMATION AROUND DENTAL IMPLANT IN THE RABBIT : A HISTOMORPHOMETRIC AND REMOVAL TORQUE STUDY.
Yang Jin YI ; Jae Ho YANG ; Sun Hyung LEE ; Yung Soo KIM ; Sang Ho KWON
The Journal of Korean Academy of Prosthodontics 2001;39(6):659-681
Platelet-rich plasma (PRP) has been known to increase the rate and degree of bone formation by virtue of growth factors in concentrated platelets. Although its great healing effect on bone defect or pre-implantation site preparation in conjunction with bone substitute has been reported, the effect associated with implant is unknown. The purpose of this study was to investigate the effect of PRP on rapid osseointegration of endosseous dental implants in the rabbit tibiae. Twenty two adult female New Zealand white rabbits, weighing approximately 2.7-3.3kg, were used for this study. Twelve of the 22 animals were used for histomorphometric analysis and ten of the 22 were for removal torque test. Each animal received two implants in each tibia (two treated with PRP and two as control) and was given fluorochrome intramuscularly. For histomorphometric analysis, rabbits were divided into four groups according to the healing period. At 1 week, 2 weeks, 4 weeks and 8 weeks postoperatively, each three animals were sacrificed serially and the amount and rate of bone formation around dental implant were examined on the undecalcified sections under fluorescent microscope, polarized microscope and light microscope connected to a personal computer equipped with image analysis system. For removal torque test, rabbits were divided into two groups and removal torque tests were performed at 4 weeks, 10 weeks after implant placement. In total, 88 screw shaped, commercially pure titanium implants (Neoplant, Neobiotech, Seoul, Korea) were used in this study. Labeling pattern reflected differences of two groups in bone formation rate at each period. Histomorphometrically, PRP group showed significantly higher bone volume within threads compared to control group at 2 weeks (70.30+/-4.96% vs. 50.68+/-6.33%; P<.01) and 4 weeks (82.59+/-5.94% vs. 72.94+/-4.57%; P<.05). PRP group at 1, 2 and 4 weeks revealed similar degree of bone volume formation comparable to control group at 2, 4 and 8 weeks, respectively. On the other hand, while PRP group showed higher bone-implant contact (47.37+/-8.09%) than control group (33.16+/-13.47%) at 2 weeks, there were no significant differences between PRP group and control group for any experimental period. Removal torque values also showed no significant differences between PRP group and control group at any experimental period (P>.05). These findings imply that PRP could induce rapid, more bone formation around implant during early healing period and get faster secondary stability for reducing healing period, though it has not induced bone maturation enough to resist functional loading.
Adult
;
Animals
;
Bone Substitutes
;
Dental Implants*
;
Female
;
Hand
;
Humans
;
Intercellular Signaling Peptides and Proteins
;
Microcomputers
;
Osseointegration
;
Osteogenesis*
;
Platelet-Rich Plasma*
;
Rabbits
;
Seoul
;
Tibia
;
Titanium
;
Torque*
;
Virtues
4.A study on the changes of bone mineral density during lactation.
Sung Keun ROH ; Sung Ho LIM ; Moon Yung KIM ; Eun Sung KIM ; Ho Won HAN ; In Kwon HAM
Korean Journal of Obstetrics and Gynecology 1993;36(7):2313-2318
No abstract available.
Bone Density*
;
Female
;
Lactation*
5.A study on the changes of bone mineral density during lactation.
Sung Keun ROH ; Sung Ho LIM ; Moon Yung KIM ; Eun Sung KIM ; Ho Won HAN ; In Kwon HAM
Korean Journal of Obstetrics and Gynecology 1993;36(7):2313-2318
No abstract available.
Bone Density*
;
Female
;
Lactation*
6.An Anesthetic Experience in a Patient with Niemann-Pick Disease: A case report.
Jun Hwa LEE ; Woo Suk JUNG ; Ho Yung LEE ; A Reum KIM ; Hee Suk YOON ; Yung Kwon GO
Korean Journal of Anesthesiology 2008;54(1):109-112
Niemann-Pick disease (NPD) is an autosomal recessive, lipid storage disorder caused by the deficiency of the lysosomal enzyme sphingomyelinase or defective cholesterol transport from lysosome to cytosol. The clinical symptoms and signs include dysphagia, loss of motor function, hepatosplenomegaly, recurred respiratory infections, seizure, mental retardation, spasticity, myoclonic jerks and ataxia, but vary depending on the type of this disease. We report a successful anesthetic experience, including endotracheal intubation with Glidescope under propofol and remifentanil infusion without neuromuscular blockade, in a 21-year old woman with Niemann-Pick disease for wound revision of gastrostomy site.
Ataxia
;
Cholesterol
;
Cytosol
;
Deglutition Disorders
;
Female
;
Gastrostomy
;
Humans
;
Intellectual Disability
;
Intubation, Intratracheal
;
Lysosomes
;
Muscle Spasticity
;
Myoclonus
;
Neuromuscular Blockade
;
Niemann-Pick Diseases
;
Piperidines
;
Propofol
;
Respiratory Tract Infections
;
Seizures
;
Sphingomyelin Phosphodiesterase
7.A Case of Irreversible Acute Renal Failure and Deafness and Visual Loss After Sodium Bromate Poisoning.
Byung Ho NA ; Kyu Nam PARK ; Seung Pil CHOI ; Eun Yung YU ; Kwan Mo YANG ; Te Wook KWON ; Won Jae LEE ; Se Kyung KIM
Journal of the Korean Society of Emergency Medicine 1997;8(4):631-636
A 39-year-old hairdresser developed sodium bromate poisoning after drinking a cup of hair neutralizer in a suicide attempt. This is the first case of visual loss afteringestion of sodium bromate. Only few cases are as a cause of acute renal failure reported in medical literature. She presented 1 day later with anuria, required hemodialysis. Sensorineural hearing loss, often a characteristic finding, was developed.
Acute Kidney Injury*
;
Adult
;
Anuria
;
Deafness*
;
Drinking
;
Hair
;
Hearing Loss, Sensorineural
;
Humans
;
Poisoning*
;
Renal Dialysis
;
Sodium*
;
Suicide
8.Recurrence of Brain Tumors in Patients Treated with Growth Hormone.
Duk Hee KIM ; Hyun Wook CHAE ; Mi Yung KWON ; Ho Seong KIM
Journal of Korean Society of Pediatric Endocrinology 2007;12(2):99-103
PURPOSE: Growth hormone (GH) has been used successfully in the treatment of short stature secondary to GH deficiency in survivors of childhood brain tumors. There has been concerned that GH might increase the risk of tumor recurrence in spite of improvement of growth. METHODS: Data for tumor recurrence from 1997 to 2006 were analysed retrospectively in 56 patients with craniopharyngioma, 78 patients with medulloblastomas, 14 patients with germinomas and 139 patients with astrocytomas or gliomas after GH treatment. Serum insulin-like growth factor (IGF)-1 and IGF binding protein (IGFBP)-3 were measured. RESULTS: 57 GH deficient and growth retarded patients (17.4%) were treated with recombinant human GH and followed up 60 months after starting GH treatment. 6 patients (10.5%) (5 craniopharyngioma, 1 germinoma) were recurred among patients with GH therapy, but 17 patients (5.2%) were recurred among patients with non GH therapy. Tumor recurrence in GH treated group was not higher than in non GH treated group. There was no significant change in serum IGF-1, IGFBP-3 level and IGF-1/IGFBP-3 ratio. CONCLUSION: Tumor recurrence rates in surviving patients with brain tumors receiving GH treatment do not appear to be increased compared with non GH treatment. However, longer follow-up regarding recurrences and secondary neoplasms remains to be essential.
Astrocytoma
;
Brain Neoplasms*
;
Brain*
;
Carrier Proteins
;
Craniopharyngioma
;
Follow-Up Studies
;
Germinoma
;
Glioma
;
Growth Hormone*
;
Humans
;
Insulin-Like Growth Factor Binding Protein 3
;
Insulin-Like Growth Factor I
;
Medulloblastoma
;
Recurrence*
;
Retrospective Studies
;
Survivors
9.Follow-up Magnetic Resonance Imaging Study of Patients with Herniated Lumbar Intervertebral Disc Who Were Treated Conservatively.
Eun Kyoung KIM ; Chang Sub YANG ; Sung Ki MIN ; Byung Jun JUNG ; Won Yung LEE ; Jung Ho KWON
Journal of the Korean Academy of Rehabilitation Medicine 1998;22(3):587-594
OBJECTIVE: To clarify the relationship between the morphologic changes of disc herniation and the clinical course of conservatively treated herniated lumbar disc patients. METHOD: Follow-up MRIs and clinical assessments by the Visual Analogue Scale and Japanese Orthopaedic Association(JOA) Score were performed in 20 patients at a mean interval of 11.3 month. RESULTS: An average reduction ratio of herniation on the sagittal and axial images, were 21.4% and 20.8% respectively. The clinical features improved significantly and the degree of clinical improvement correlated with the reduction ratio of herniation, althougy 4 patients improved symptomatically despite increased or unchanged degree of herniation. Ten patients with extruded discs showed a higher reduction ratio of heniation with better clinical outcome than those with protruded discs. CONCLUSION: The morphologic change verified on MRI of conservatively treated patients with a lumbar disc herniation is responsible for the clinical outcome although the anatomical factor alone is not enough to explain the outcome. The patients with extruded disc herniation shows more morphologic changes on MRI and better clinical outcomes than the patients with protruded discs.
Asian Continental Ancestry Group
;
Follow-Up Studies*
;
Humans
;
Intervertebral Disc*
;
Magnetic Resonance Imaging*
10.Three-dimensional accuracy of different correction methods for cast implant bars.
Ji Yung KWON ; Chang Whe KIM ; Young Jun LIM ; Ho Beom KWON ; Myung Joo KIM
The Journal of Advanced Prosthodontics 2014;6(1):39-45
PURPOSE: The aim of the present study was to evaluate the accuracy of three techniques for correction of cast implant bars. MATERIALS AND METHODS: Thirty cast implant bars were fabricated on a metal master model. All cast implant bars were sectioned at 5 mm from the left gold cylinder using a disk of 0.3 mm thickness, and then each group of ten specimens was corrected by gas-air torch soldering, laser welding, and additional casting technique. Three dimensional evaluation including horizontal, vertical, and twisting measurements was based on measurement and comparison of (1) gap distances of the right abutment replica-gold cylinder interface at buccal, distal, lingual side, (2) changes of bar length, and (3) axis angle changes of the right gold cylinders at the step of the post-correction measurements on the three groups with a contact and non-contact coordinate measuring machine. One-way analysis of variance (ANOVA) and paired t-test were performed at the significance level of 5%. RESULTS: Gap distances of the cast implant bars after correction procedure showed no statistically significant difference among groups. Changes in bar length between pre-casting and post-correction measurement were statistically significance among groups. Axis angle changes of the right gold cylinders were not statistically significance among groups. CONCLUSION: There was no statistical significance among three techniques in horizontal, vertical and axial errors. But, gas-air torch soldering technique showed the most consistent and accurate trend in the correction of implant bar error. However, Laser welding technique, showed a large mean and standard deviation in vertical and twisting measurement and might be technique-sensitive method.
Axis, Cervical Vertebra
;
Welding