1.A STUDY OF THE STRESS DISTRIBUTION OF THE ABUTMENT AND SUPPORTING TISSUES ACCORDING TO THE SLOPES AND TYPES OF GUIDING PLANES OF THE LAST ABUTMENT IN DISTAL EXTENSION REMOVABLE PARTIAL DENTURE USING THREE DIMENSIONAL FINITE ELEMENTANALYSIS METHOD.
Yang Kyo KIM ; Cheong Hee LEE ; Kwang Hun JO
The Journal of Korean Academy of Prosthodontics 1999;37(5):581-596
The purpose of this study was to investigate the stress distribution of the abutment and supporting tissues according tot he slopes and types of the guiding plane of distal extension removable partial dentures. The 3-dimensional finite element method was used and the finite element models were prepared as follows. Model I : Kratochvil type guiding plane with 90degree to residual ridge Model II : Kratochvil type guiding plane with 95degree to residual ridge Model III : Kratochvil type guiding plane with 100degree to residual ridge Model IV : Krol type guiding plane with 90degree to residual ridge Distal extension partial denture which right mandibular first and second molar were lost was used and the second premolar was prepared as primary abutment with RPI type retainer. Then 150N of compressive force was applied to central fossae of the first and second molars and von Mises stress and displacement were measured. The results were as follows : 1. Model I and Model IV showed a similar stress distribution pattern and the stress was concentrated on the apex of the root of the abutment. 2. The stress was increased and concentrated on mesial side of the root of the abutment in Model II. The stress was concentrated on buccal and mesiobuccal side of the root of the abutment in Model III. 3. In Model I, the root of the abutment displaced and twisted a little in clockwise. In Model IV, the root of the abutment displaced to distolingually at apical region of the root and mesiobucally at cervical region of the root. 4. In Model II, the root of the abutment displaced to mesiolingually at apical region of the root and more displaced and twisted in counterclockwise at cervical region of the root. In Model III, the root of the abutment displaced to mesiobucally at apical region of the root and more displaced and twisted in clockwise at cervical region of the root.
Bicuspid
;
Denture, Partial
;
Denture, Partial, Removable*
;
Molar
2.FITNESS TEST USING THE PHASE-SHIFTING PROFILOMETRY ACCORDING TO THE DENTURE CURING METHODS.
Cheong Hee LEE ; Kwang Hun JO ; Boo Byung CHOI
The Journal of Korean Academy of Prosthodontics 1999;37(4):474-493
According to repeated measurements and correction procedures, the accuracy of the phase-shifting profilometry was developed. At first, after 20 final models for maxillary complete denture were duplicated, the mucosa surfaces of models were measured with the phase-shifting profilometry and each mirror view of these was calibrated. Maxillary cats were divided into 4 groups of 5 casts per each, and wax dentures with 2 sheets of baseplate wax and artificial teeth were made and then cured according to the curing method of each group. Group I ; quick curing with QC-20 acrylic resin Group II ; 9 hour curing with QC-20 acrylic resin Group III ; SR-Ivocap system Group IV ; metal base and quick curing with QC-20 acrylic resin After curing, polishing, and storing at 37degrees C n saline for 30 days, the forms of the impression surface of the dentures were measured with the phase-shifting profilometry. Then, the impression surface form of each denture was placed in the optimal position of comparison with the mirror view of the same final cast. The amount and direction of distortion of each denture was analyzed and the effects of polishing and storage in each denture were compared. The obtained results were as follows : 1. In Group I, the denture was observed as the appearance distorted in the opposite direction of the mucosa and the postero-lateral part of palatal portion of the denture was observed as the appearance separated from the mucosa. Also, the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa. 2. In Group II, the postero-lateral part of palatal portion of the denture was observed as the appearance separated slightly from the mucosa. The bilateral buccal flanges of denture were observed as the appearance distorted severely in the direction of the mucosa. 3. In Group III, the bilateral part of the residual ridge crest portions and the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa, and specially, the buccal flanges of the maxillary tuberosities were distorted severely. 4. In Group IV, the acrylic resin base of the buccal portion of the denture was observed as the appearance distorted in the opposite direction of the mucosa. 5. The phase-shifting profilometry, done with repeated measurements and correction procedures, was effective in comparing the amount and direction of distortion at every position after the laboratory work and the delivery of maxillary complete denture.
Animals
;
Cats
;
Denture, Complete
;
Dentures*
;
Mucous Membrane
;
Tooth, Artificial
3.SHEAR BOND STRENGTH OF PRETREATED DENTIN SURFACE WITH RESIN-REINFORCED GLASS IONOMER CEMENT.
Hye Souk CHOI ; Cheong Hee LEE ; Kwang hun JO
The Journal of Korean Academy of Prosthodontics 2001;39(5):502-513
The purpose of this study was to evaluate the effect of dentin pretreatment with Dentin Conditioner,Ultra-Etch,conditioner of Fuji Plus cement on the shear bond strength of resin-reinforced glass ionomer cements to dentin and analyze the fractured surfaces. To evaluate the bond strengh, the extracted human teeth which had uniform area of exposed dentin were cemented with conventional glass ionomer cement. 3M RelyX TM Luting (Vitremer luting cement). Fuji Plus cement after dentin pretreatment. The shear bond strengh was measured using the Universal testing machine(Instron Co., USA) with a crosshead speed of 1mm/m. The effect of dentin pretreatment was evaluated by observing pretreated dentin surfaces under the scanning electron microscope,measuring the shear bond strength and observing the fractured surfaces under the scanning electron microscope. The results were as follows: On the SEM observation of surface morphology, the specimens treated with Dentin Conditioner, Ultra-Etch and conditioner of Fuji Plus cement were removed the smear layer and funneled dentinal tubules in dentin surfaces. In RelyX TM Luting cement group, shear bond strengh of pretreated group was significantly higher than control group. In Fuji Plus cement group and Fuji I group, regardless of the type of pretreatment agents, there was tendency of increase in the shear bond strength. On the SEM observation of fractured surfaces, as the shear bond strength increase, it were shown thicker cement layers and were not shown dentinal tubules. According to these results, it were shown that dentin pretreatment have much effect on bonding states.
Dentin*
;
Glass Ionomer Cements*
;
Glass*
;
Humans
;
Smear Layer
;
Tooth
4.Two Cases of Right Homonymous Hemianopsia and Total Blindness due to Cerebral Paragonimiasis.
Jae Wook PYUN ; Wan Hun KOO ; Jung Jo HUANG
Journal of the Korean Ophthalmological Society 1966;7(1):27-30
We present two cases of cerebral paragonimiasis in a 23-year-old Korean army soldier and in a 18-year-old Korean girl, respectively. The diagnosis was made on the basis of clinical, laboratory and x-ray findings, and was confirmed by the histopathological examination of the excised cyst. P.W. skin test showed positive reaction, whereas C.S. test negative. X-ray study on skull revealed multiple globulated round cystic formations in occipital region. Two months after surgical removal of cysts, visual field were not improved. Pertinent literatures are reviewed.
Adolescent
;
Adult
;
Blindness*
;
Choroid*
;
Coloboma*
;
Diagnosis
;
Female
;
Hemianopsia*
;
Heredity
;
Humans
;
Iris*
;
Membranes
;
Military Personnel
;
Optic Nerve*
;
Paragonimiasis*
;
Skin Tests
;
Skull
;
Visual Fields
;
Young Adult
5.Surgical Treatment of the Congenital Esophageal Atresia.
Pil Jo CHOI ; Hee Jae JUN ; Yong Hun LEE ; Kwang Jo JO ; Si Chan SUNG ; Chong Su WOO
The Korean Journal of Thoracic and Cardiovascular Surgery 1999;32(6):567-572
BACKGROUND: Surgical correction of the full spectrum of esophageal atresia with tracheoesophageal fistula has improved over the years, but the mortality and morbidity assoiated with repair of these anomalies still remains high. MATERIAL AND METHOD: We retrospectively analyzes 27 surgically treated patients with esophageal atresia and tracheoesophageal fistula at Dong-A University Hospital between January 1992 and March 1997. RESULT: There were 21 male and 6 female patients. Mean birth weight was 2.62+/-.385 kg(2.0~3.4 kg). Twenty- four(88.9%) had esophageal atresia with distal tracheoesophageal fistula, and 3(11.1%) had pure esophageal atresia. Four(14.8%) infants were allocated to Waterston risk group A, 18(66.7%) to group B, and 5(18.5%) to group C. In eighteen(66.7%) infants with associated anomalies, cardiovascular anomalies were the most common. Three had a gap length of 3.5 cm or greater(ultra-long gap) between esophageal segments, 7 had 2.0 to 3.5 cm(long gap), 8 had 1.0 to 2.0 cm(medium gap), and 9 had 1 cm or less(short gap) gap length. Among 27 neonates, 3 cases underwent staged operation, late colon interposition was done in 2, and all other 24 cases underwent primary esophageal anastomosis. Oerative mortality was 2/27(7.4%). Causes of death included acute renal failure(n=1), empyema from anastomotic leak(n=1), necrotizing enterocolitis(n=1), sepsis(n=1), insulin-dependent diabetus mellitus(n=1 . There were 4 anastomosis- related complications including stricture in 3, leakage in 1. Mortality was related to the gap length(p<.05). CONCLUSION: Although the complication rate associated with surgical repair of these anomalies is high, this does not always implicate the operative mortality. The overall survival can be improved by effective treatment for combined anomalies and intensive postoperatve care.
Birth Weight
;
Cause of Death
;
Colon
;
Constriction, Pathologic
;
Empyema
;
Esophageal Atresia*
;
Female
;
Humans
;
Infant
;
Infant, Newborn
;
Male
;
Mortality
;
Retrospective Studies
;
Tracheoesophageal Fistula
6.A Case of Tick Bite Caused by Ixodes Species.
Won Hyoung KANG ; Kyung Hun CHANG ; Soo Ill CHUN ; Chang Jo KOH ; B K CHO
Korean Journal of Dermatology 1982;20(5):789-793
The importance of the ticks in medical field has been emphasized because of their association with and transmission of various diseases. We report herein a case of tick bite in a 55-year-old male farmer, who visited our hospital on July 2, 1981 with a parasite attached on right lower flank and rice to small pea sized, pruritic erythematous papular skin eruptions on chest and right lower flank. The skin lesions disappeared completely with.in five days after removal of the parasite, which was identified with an adult female tick which belongs to Genus Ixodes.
Adult
;
Female
;
Humans
;
Ixodes*
;
Male
;
Middle Aged
;
Parasites
;
Peas
;
Skin
;
Thorax
;
Tick Bites*
;
Ticks*
7.ANALYSIS OF STRESS DEVELOPED WITHIN THE SUPPORTING TISSUE OF ABUTMENT TOOTH WITH INDIRECT RETAINER ACCORDING TO VARIOUS DESIGNS OF DIRECT RETAINER AND DEGREE OF BONE RESORPTION.
Suk Hyun LEE ; Cheong Hee LEE ; Kwang Hun JO
The Journal of Korean Academy of Prosthodontics 1998;36(1):150-165
For the purpose of evaluating the effect of both direct retainer design and bony absorption degree around abutment of indirect retainer on the supporting tissue of abutment of indirect retainer, dislodging force was transmitted to unilateral distal extension RPD bases. Analysis of stress distributed within the supporting tissue around abutment of indirect retainer was carried out. Using three-dimensional photoelastic stress analysis method and the conclusion is a follows. 1. According to the extent of force which the direct retainer of the most distal abutment tooth, the amount of force transmitted to the abutment tooth of indirect retainer was small. 2. Of all the cases, Mandibular first premolar which was used abutment tooth of indirect retainer, buccal, mesial and distal sides represented compression stress and lingual side represented tensile stress. 3. The more bone resorption of abutment tooth of indirect retainer, the more distortion of buccal and distal side of abutment tooth was existed and the extent of compression stress which was existed and distal side to abutment tooth was large. 4. When the alveolar bone around the abutment with indircet retainer is normal. The amount of force transmitted on abutment with indirect retainer was small in the order of Akers clasp, RPA clasp, RPI clasp. 5. When the alveolar bone around the abutment with indirect retainer has been absorbed 20% and 30%, the amount of force transmitted on abutment with indirect retainer was small in the order of RPA calsp, RPI clasp, Akers clasp. 6. When denture is displaced, shape of the direct retainer reciprocating abutment affect much the function of indirect retainer.
Absorption
;
Bicuspid
;
Bone Resorption*
;
Dentures
;
Tooth*
8.ANALYSIS OF PORCELAIN SURFACE ROUGHNESS POLISHED BY VARIOUS TECHNIQUE.
Kyu Young LEE ; Chung Hee LEE ; Kwang Hun JO
The Journal of Korean Academy of Prosthodontics 1998;36(3):506-513
This study was designed to compare the smoothness by glazing method with that by polishing method after 48 specimens of Ceramco II block, one of porcelain materials used for PFM, were baked according to the manufacturer's directions. The specimens were roughened with new green stone at 15,000rpm for 30 seconds and sandblasted with 25microliteraluminum oxide for 15 seconds. They were divided into 4 groups at random, and 4 groups were prepared as follows : Group I : specimens were autoglazed and overpolished with polishing system. Group II specimens were polished with only polishing system. Group IIIspecimens were glazed after adding glazing liquid, vitachrom "L"-fluid (vita zahnfabrik co. Germany) to the rough surface Group v : specimens were just autoglazed Using the surface roughness tester, Ra, Rmax, and Rz were estimated 5 times per specimen, and recording process of mean value was repeated 3 times. The results were as follows : 1. The Ra of group I and group IIwas lower than group IIIand group IV (p<001). 2. There was lower value of Rz in group I and group II than group III and group IV (p<001). 3. The Rmax of group I(overpolished with polishing system after autoglazing) and group II(polished with only polishing system) was lower than group III(glazed after adding glazing liquid) and group IV (autoglazed) (p<001). 4. There was not a statistically significant difference between group I and II and between group III and IV (p>001). 5. The roughness was increase in order of group I,II,III,IV in SEM
Dental Porcelain*
9.Speckled Lentiginous Nevus.
Choong Seop HAHN ; Jung Bock LEE ; Seung Hun LEE ; Yoon Kee PARK ; Chang Jo KOH
Korean Journal of Dermatology 1981;19(3):353-358
Speckled lentiginous nevus is a clinical variant of nevus-cell nevus first described by Stewart et al. in 1978. It is characterized by small, dark hyperpigmentated speckles superimposed on a tannish-brown background. The speckled areas show varying histologic patterns ranging from nevus incipiens to junctional or compound nevus. The back ground shows histologic features of Ientigo simplex. Recently, we observed clinical and histological features of 5 cases of speckled lentiginous nevi. The age of onset ranges from birth to infancy, The locations are face, thigh, back and scapula. One has zosteriform distribution in upper extrernity, chest and back. Histologic features of speckles are junctional or compound nevus. We suggest that the origin of dark speckles may be from the tannish-brown background, lentigo simplex.
Age of Onset
;
Lentigo
;
Nevus*
;
Parturition
;
Scapula
;
Thigh
;
Thorax
10.The Effects of Intravenous Administration of Nimodipine on Cerebral Pial Vessels Following the Injection of Autogenous Hemolytic Blood into Cisterna Magna in Rabbits.
Journal of Korean Neurosurgical Society 1995;24(3):278-289
The reactions of cerebral pial vessels following the injection of normal saline(0.05cc, at 37 degrees C, pH7.4) and autogenous hemolytic blood(0.05cc, 0.1cc 0.2cc) into the cisterna magna of rabbits were tested in vivo. This experiment was performed in order to observe the effect of intravenous nimodipine(30 microgram/kg) injection at the maximally constricted time of the pial vessels, about 6 hours after intracisternal injection of autogenous hemolytic blood. The diameter changes of the pial vessels were measured under operating microscope through a cranial window on craniectomized area. Pial vessels were not significantly changed after an intracisternal injection of normal saline. But after intracisternal injection of autogenous hemolytic blood(0.05cc, 0.1cc, 0.2cc), pial vessels were maximally constricted at 6 hours and the constriction was continued during the experiments. Percentile constriction was increased as the amount of subarachnoid hemolytic blood increased. According to the results, pial vessels, especially small pial artery, were constricted by autogenous hemolytic blood containing oxyhemoglobin. Nimodipine, calcium antagonist, showed dilating effect on vasospasm after experimental subarachnoid hemorrhage with autogenous hemolytic blood in rabbits.
Administration, Intravenous*
;
Arteries
;
Calcium
;
Cisterna Magna*
;
Constriction
;
Nimodipine*
;
Oxyhemoglobins
;
Rabbits*
;
Subarachnoid Hemorrhage