Taehan Ch'ikkwa Uisa Hyophoe chi最新文献

In 1989, there were 8893 injured policemen by various demonstrations. This injury ratio (8893/130,000) is about 3 times higher than other occupations. Of them, 2869 (31%) were treated at National Police Hospital, and 13% of which were facial injuries. The most common etiologic factor of facial injuries was demonstrations by Univ. students (89.2%), and 93.9% of the victims were injured by thrown stone.

According to Dr. Niznick's alternative two-stage surgical technique, the author installed 3.5 mm x 8 mm Core-Vent Implant (Core-Vent Corporation, Encino, CA, U.S.A.) as a free standing abutment to replace lower left second premolar of 50-year-old male patient. From the foregoing procedure the author obtained the following results: 1. Free-standing Core-Vent Implants can be used to replace single premolar effectively without reduction of adjacent natural teeth. 2. Rotation of screw-in titanium insert (abutment) was observed under occlusal force. 3. Adjustment of height of titanium coping insert was necessary. 4. From the oral examination, patient comments, panoramic and periapical radiograph, there were no evidences in gingival inflammation, pain, reduction of alveolar bone level during the observation period of 13 months postoperatively.

The author has made clinical studies on treatment of fractures of the zygomatic bone in terms of frequency of fractures according to sex, age, fracture type, main manifestations and treatment methods from 106 patients with zygomatic bone fractures among 969 patients with maxillofacial bone fractures. The results obtained were as follow: 1. The frequency of malar bone fracture was 4 times more in male than that in female. 2. The most prevalent age of malar bone fracture was 21-30 years of age, and the nexts were followed 11-20, 31-40, 0-10, 41-50, 51-60, 61-70, and over 71 in the orders. 3. Among maxillofacial bone fractures, mandibular fracture was most prevalent as 76.3%, and the nexts were followed by the maxilla (10.8%), the molar bone (9.7%) and the nasal bone (3.3%). 4. Among 106 fractures of the malar bone, zygomatic bone fracture only was occupied 48.1%, but the rests were accomplished by another maxillofacial bone fractures. 5. In classification of molar bone fractures according to Knight and North's, group 3 fractures were most prevalent, and followed by group 2, 1, 4 and 6 in the orders. 6. Main manifestations were upper cheek flattening, lower eyelid ptosis, subconjunctival ecchymosis, epistaxis, difficulty of mouth opening, pain during mouth opening and others in the orders. 7. 93.4% of malar bone fracture has been treated surgically, but the rests treated conservatively, and [symbol: see text] shaped elastic stapler wire has been effectively used to get fixation at zygomatico-maxillary fractures.

This is an age-by-age summation of literature on over 100 sites (of more than 250 excavated prehistoric ruins on the Korean Peninsula: about 160 places in South Korea--Paleolithic Age 15, Neolithic Age 21, Bronze Age 90 and Iron Age 35--and about 90 places in North Korea) which produced dietary-habit-related devices such as hunting tools, fishing instruments, farming equipments, tools of daily life, and human bones and teeth. 1) Various dietary-habit-related Old Stone-Age tools, instruments and other items were found. Among them were stone axes, stone hand axes, fish spears and hooks made of bone or horn, stone blades, stone scrapers and stone drills believed to have been used in daily life, and charcoal and sites of furnaces used for cooking. Furthermore, it was found that there were severe dental abrasions and dental caries among the inhabitants of the Korean Peninsula in the Old Stone Age. 2) Some evidences were found which lead us to believe that hunting was practiced with stone arrowheads in the New Stone Age. Stone net sinkers, which is the evidence of the use of fish nets, were also found. In addition, farming stone tools and charred cereals, both of which date back to the latter part of this period, were unearthed. Millstones, which began to be used in this age, and livestock bones were found. Where these items were discovered, 23 maxillae and mandibles with teeth and a total of 231 separate teeth of Neolithic period human beings were reported. However, there are no records indicating dental caries, but some records describe severe abrasion.

It is recommended that the chair-side dental assistant should be utilized in order to increase the production of dental health care by World Health Organization. In the Republic of Korea, there was no chair-side dental assistant by legally. So the authors investigated and discussed for the development of chair-side dental assistant in Korea. Obtained results were as follows 1. In order to increase the production of dental health care chair-side dental assistants should be developed. 2. Institution of chair-side dental assistant will be established legally. 3. Trained chair-side dental assistant will be positioned in dental clinics for dentist and health centers for dental public health.

The study was to evaluate the toxicity of self curing resins in vitro. Fibroblasts (established cell L-929) were cultured in alpha-MEM with 4 different resins. Each resin was mixed by the instruction and filled in open end cylinder. These cylinder was placed at the centre of the dish. Millipore filter (pore size, 0.22Um) was also placed between the bottom of the cylinder and the dish. As a control group cylinder without resin was employed in this experiment. The culture dishes were then stored in 5% CO2 containing incubator for 5 days at the temperature of 36.6 degrees C. The results were observed microscopically. 1. Two groups showed least cell population compare to control group. (This indicated greater cytotoxicity). 2. Remaining two groups revealed lesser cell population compared to control group. (This indicated lesser cytotoxicity).

An overdenture is a complete denture supported by both soft tissue and a few remaining natural teeth. The purpose of this study was to analyze the stress distribution of the teeth and supporting structures when various type of coping under overdenture was applied. The analysis was conducted by using the finite element method and changing the condition such as the direction of the load, the shape of coping on the abutment: The model included overdenture copings, abutment tooth and supporting structures. The results of analysis were as follows: 1. The short dome coping showed well distribution of stress. 2. The dome shaped design produced higher stress distribution than square and inclined plane design. 3. As the height of copings on the abutment was increased, the displacements increased. 4. The magnitude and direction of the abutment displacements were influenced by the direction of load application.

The maintenance of good oral hygiene in patients with or without prosthesis has been one of the essential parts of the total oral health care. Recently a redesigned air-powder abrasive system was introduced to remove dental plaque and stain from tooth surfaces. This study was designed to evaluate effects of this device on the cementoenamel junction area quantitatively and qualitatively by using the Michigan Computer Graphic Coordinate Measuring system (MCGCMS) and scanning electron microscopy (SEM) after exposure to an air-powder abrasive device. A tooth specimen was exposed to a Cavi-Jet (Dentsply International Inc., York, PA) for 10, 30, 90 seconds intervals. The MCGCMS was utilized before and after treatment of the specimen at each time interval to measure the depth abrasion of the tooth material, and SEM pictures were taken after 90 seconds treatment of the specimen to evaluate surface characteristics. Following conclusions were drawn within the limits the confines of this study. 1. An air-powder abrasive device abrades cementum rapidly and should be used carefully below cementoenamel junction. 2. There was no significant change on the enamel surface quantitatively. 3. The MCGCMS reproduces and measures experimental points accurately.

The author investigated the origin of two linear radiopaque images superimposed upon the lower part of the maxillary antra and nasal cavity. The obtained results were as follows: 1. The upper blurred image was not the ghost image of the lower sharp image. 2. The upper image was not formed by the horizontal plate of palatine bone and the lower image was not formed by the palatal process of maxilla. 3. The upper image and lower image seemed to be formed by the junction of the nasal septum to the hard palate and by the junction of the maxillary antrum and the hard palate respectively. But there were some unidentified structures which formed these two images.

It has been known for many years that tooth extraction can cause bacterial dissemination into blood stream, that is, bacteremia. Besides endocarditis--causing bacteria, alpha-hemolytic streptococci, anaerobes are involved in the post- extraction bacteremia. They are of clinical importance because they can cause abscesses in the various parenchymatous organs such as the liver, lung, and brain through anachoresis. The purpose of this study is to establish the types of species of anaerobes associated with post--extraction bacteremia, and to give the baseline to the succeeding study of sensitivity tests of various antibiotics, thus clinicians can chose the right ones. 10ml of blood was sampled pre- and post- operatively from 32 patients and incubated in anaerobic chamber. The followings are the results of this study. 1. All the preoperative blood samples showed negative culture. 2. Postoperative blood samples from 8 out of 10 patients (80%) in group 1, from 1 out of 15 (73.3%) in group 2, and 2 out of 7 (28.6%) in group 3 yielded anaerobic and facultative species. 3. Organisms detected were species belonging to the genera Streptococcus, Bacteroides, Actinomyces, Staphylococcus, Peptostreptococcus, Peptococcus, Propionebacterium, Fusobacterium, nonenterococcus, and Corynebacterium.