• 구강회복응용과학지
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• 제33권1호
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• pp.19-24
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• 2017

탄성의치는 심미성, 유연성, 생체적합성 등의 장점이 있어서 최근 많이 사용되고 있다. 그러나 재료 자체의 유연성에 의한 의치의 운동 때문에 안정성에 대한 문제가 제기되고 있다. 저작 시 의치가 조직면으로 움직이면서 지지조직을 자극하게 되고, 이런 자극이 장기간 지속될 경우 외상과 잔존치조제의 급속한 흡수를 야기할 수 있기 때문이다. 본 증례에서는 안정, 유지 및 지지가 부족한 탄성의치를 장기간 사용하면서 지지점막의 지속적인 자극으로 인한 구개골 노출이 발생하였다. 안정성 및 유지력이 확보된 새로운 의치를 제작하여 환자의 불편감이 감소하였고 구개골 노출이 치유되었다. 탄성의치를 사용할 수 있는 증례를 신중하게 선택해야 하며 정기검진 및 적절한 처치를 시행하여 부작용을 예방할 수 있어야 한다.

• 대한치과보철학회지
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• 제36권5호
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• pp.701-720
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• 1998

Research advances in dental implantology have led to the development of several different types of materials and it is anticipated that continued research will lead to advanced dental implant materials. Currently used pure titanium has relatively low hardness and strength which may limit its ability to resist functional loads as a dental implant. Ti-6Al-4V also has potential problems such as corrosion resistance. osseointegration properties and neurologic disorder due to aluminium and vanadium, known as highly toxic elements, contained in Ti-6Al-4V. Newly developed titanium based alloys(Ti-20Zr-3Nb-3Ta-0.2Pd-1In, Ti-20Zr-3Nb-3Ta-0.2Pd) which do not contain toxic metallic components were designed by the Korea Institute of Science and Technology (KIST) with alloy design techniques using Zr, Nb, Ta, Pd, and In which are known as non-toxic elements. Biocompatibility and osseointegration properties of these newly designed alloys were evaluated after implantation in rabbit femur for 3 months. The conclusions were as follows : 1. Mechanical properties of the new designed Ti based alloys(Ti-20Zr-3Nb-3Ta-0.2Pd-1In, Ti-20Zr-3Nb-3Ta-0.2Pd) demonstrated close hardness and tensile strength values to Ti-6Al-4V. 2. New desinged experimental alloys showed stable corrosion resistance similar to the pure Ti but better than Ti-6Al-4V. However, the corrosion rate was higher for the new alloys. 3. Cell culture test showed that the new alloys have similar cell response compared with pure Ti and Ti-6Al-4V with no cell adverse reaction. 4. New designed alloys showed similar bone-metal contact ratio and osseointegration properties compared to pure Ti and Ti-6Al-4V after 3 months implantation in rabbit femur. 5. Four different surface treatments of the metals did not show any statistical difference of the cell growth and bone-metal contact ratio.

• Journal of Periodontal and Implant Science
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• 제36권4호
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• pp.879-889
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• 2006

The early exposure of cover screws is a common complication of 2-stage implant technique. The exposure of cover screws between stage I and IT surgery may cause inflammation in the soft tissues surrounding the implants, and lead to peri-implantitis or marginal bone loss. The purpose of this study was to evaluate the effect of the early exposure of cover screws on implants placed using 2-stage technique. Two hundred and nineteen implants in 77 patients were examined for cumulative survival rate, radiographic marginal bone level change, cause and frequency of the early exposure. The results were as follows: 1. Twenty-five implants showed early exposure of cover screws with a frequency of 11.4%. 2. Cumulative survival rate of the implants with early cover screw exposure was 88.0%, and that of the implants without cover screw exposure was 96,9%. 3. At the time of stage IT surgery and 1 year after loading, the marginal bone loss was greater around the implants with early exposure of cover screws than around the implants without cover screw exposure(p <0.05), 4, There was no statistically significant difference in the frequency of the early exposure according to the implant diameter, gender, and smoking(p >0,05).

• 구강회복응용과학지
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• 제18권4호
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• pp.321-329
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• 2002

Bending moments results from offset overloading of dental implant, which may cause stress concentrations to exceed the physiological capacity of cortical bone and lead to various kinds of mechanical failures. The purpose of this study was to compare the distributing pattern of stress on the finite element models with the different angulated placement of dental implant in mandibular posterior missing areas. The three kinds of finite element model, were designed according to 3 main configurations: Model 1(parallel typed placement of 2 fixtures), Model 2(15. distal angulated placement of one fixture on second molar area), Model 3(15. mesial angulated placement of one fixture on second molar area). The cemented crowns for mandibular first and second molars were made on the two fixtures (4mm 11.5). Three-dimensional finite element models by two fixtures were constructed with the components of the implant and surrounding bone. A 200N vertical static load were applied to the center of central fossa and the point 2mm apart from the center of central fossa on each model. The preprocessing, solving and postprocessing procedures were done by using FEM analysis software NISA/DISPLAY IV Version 10.0((Engineering Mechanics Research Corporation, USA). Von Mises stresses were evaluated and compared in the supporting bone, fixtures, and abutment. The results were as following : (1) Under the point loading at the central fossa, the direction of angulated fixture affected the stress pattern of implants. (2) Under the offset loading, the position of loading affected more on the stress concentration of implants compare to the angulated direction of implants. The results had a tendency to increase the stress on the supporting bone, fixture and screw under the offset loads when the placement angulation of implant fixture is placed toward mesial or distal direction. In designing of the occlusal scheme for angulated placement, placing the occlusal contacts axially during chewing appears to have advantages in a biomechanical viewpoint.

• The Korean Journal of Ecology
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• 제24권5호
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• pp.303-307
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• 2001

집비둘기 Columba livia의 서식 환경별로 중금속 오염정도를 알아보기 위하여 서울시 관내의 상업지역, 공업지역, 공원지역 및 주거지역에서 집비둘기를 채집하여 간, 콩팥, 뼈, 근육 등 4개 조직에 함유된 중금속 농도를 측정하고 지역별로 비교하였다. 대부분의 중금속 원소 농도는 서식환경에 따라 유의한 차이를 나타내었다. 주거지역에 서식하는 집비둘기의 간에 함유된 철과 콩팥에 함유된 아연의 농도는 다른 지역보다 현저하게 낮았다. 망간은 모든 조직에서 공업지역이 높았으며, 구리는 모든 조직에서 공원지역이 다른 지역보다 현저히 높았다. 뼈의 납 함량은 주거지역이 가장 낮았고 상업지역이 가장 높았으며, 콩밭의 카드뮴 함량은 공원지역이 다른 지역보다 높은 것으로 나타났다. 특히 일부 조직의 철, 아연 및 납 농도는 교통량과 관련이 있는 것으로 나타났다.

• Journal of Nutrition and Health
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• 제22권3호
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• pp.185-193
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• 1989

This study was performed to investigate lead(Pb) detoxification with different dietary protein levels and detoxifying periods in Pb poisoned rats. Forty nine male rats of Sprague-Dawley strain weighing 114$\pm$4g were used and they were fed 1% Pb-15% casein diet ad libitum for 2 weeks. After sacrifying 7 animals as control group, remaining forty two rats were blocked into 6 groups according to body weight. Three groups were fed each detoxifying diet(5%, 15% or 40% casein diet without Pb) for 1 week and the other 3 groups were fed same diets for 3 weeks. The results obtained were summerized as follows ; 1) Liver and kidney weight, bone weight, and bone length were increased with increasing dietary protein level and detoxifying period. 2) Hematocrit values were recovered to normal level during detoxifiying periods but hemoglobin contents in detoxifying diet groups showed no significant difference from those in control group. 3)Pb contents in blood were decreased with increasing dietary protein level, and Pb contents in liver were significantly decreased in high protein diet groups. Pb contents in kidney were significantly decreased during detoxifying period compared to control group, but no significant difference was shown within the detoxifying diet groups. Pb contents in femur were significantly decreased after 3 weeks of detoxifying period but no difference was shown with different dietary protein level. 4) Urinary Pb excretions were significantly increased with increasing dietary protein level. Fecal Pb excretions were remarkably decreased after 3 weeks of detoxifying period, but no difference was showen in fecal Pb excretions with different dietary protein level. Above results suggest that high protein diet improves Pb detoxification by increasing urinary Pb excretion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권2호
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• pp.167-173
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• 2001

Cystic lesion of the jaw are frequently encountered clinically. Although they rarely lead to development of tumors, they can result in resorption of the jaw bone or asymmetry of the face may occur. The purpose of this study is to find the clinical and histopathological pattern of cysts and to help better understanding for the diagnosis and treatment of jaw cysts. The hospital chart, out-patient chart, panorama X-ray, histopathological report and operation report of 246 patients were reviewed who had been diagnosed as cyst. Sex distribution, age distribution, classification, anatomic distribution, clinical sign & symptoms, treatment, post-operation complications, recurrence rate were studied. Then significant difference between the diameter of cyst with bone graft and none-bone graft was calculated with SAS program. The results were as follows. 1. Among the total patient of 246 cases, male were 163 case(67.0%), and female were 83 case(37.0%), male predominated by the ratio of 1.98. 2. By age group, the 20's accounted for the largest proportion of the cases(27.2%) and the 30' accounted for the 2nd largest proportion of the case(19.5%). 3. Radicular cyst and dentigerous cyst were most common cysts, irrespective of 166 case(67.5%) and 62 case(25.2%). 4. Clinical sign & symptoms were swelling(167case), pain(85case), pus discharge(53case), teeth discoloration(28case), indicating that most complaints were related to inflammation and facial asymmetry. 4.9% of the total cases were discovered accidentally. 5. The primary site of cysts were maxillary anterior area(43.9%), the others were, in descending order, mandibular posterior area(25.6%), maxillary posterior area(14.6%). 6. Enucleation with endodontic treatment was a main treatment method(133 case, 54.1%) and 38 cases(15.4%) were enucleation with extraction, and 37 cases(15.0%) were only enucleation, and 21 cases(8.5%) were enucleation with bone graft. 7. The average diameter of cysts with bone graft was significally greater than with non-bone graft(p<0.05). 8. Post-operation complications occurred in 10 case(4.1%), all of this were due to secondary infection.

• 대한의생명과학회지
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• 제8권4호
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• pp.217-221
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• 2002

Age-related osteopenia and osteoporosis are common in postmenopausal women due to decrease in bone mass and ovarian function. A therapy for osteoporosis would depend on only drugs to inhibit bone loss, hormonal replacement therapy, exercise and dietary supplementation and it is very hard to fad an ideal therapy for osteoporosis as yet. Chlorella which is rich in minerals such as calcium magnesium fatty acids, vitamins and sterol, could be applicable for prevention and co-treatment of osteoporosis, but it has yet to be studied. The purpose of this study was to assess the relationship between the effect of dietary chlorella on bone mineral density (BMD) and nutritional improvement. BMD was measured in the femural neck and lumber spine portion. Nutritional and bone turnover markers from blood samples were assessed serum lkaline phosphatase, hemoglobin, number of erythrocytes and total protein. Studies for the femur neck measurement showed that normal BMD increased 2.1% for the group fed chlorella supplemented diet for four month and increased 6.6% fur group treated for one year when compared to the control group, and for the lumber spine measurements the few month group showed an increase of 9.1% over the control group, the one year group showed an increase of 64.2% over the control group. Hemoglobin content, number of erythrocytes and total protein showed similar increased patterns with BMD measurement, meanwhile, serum alkaline phosphatase increased 3% for the four month group and decrease 16% for the one year group compare to the control group. In conclusion, the postmenopausal women fed chlorella supplemented diet results in an increase in BMD. This is a marked increment in lumber spine, enhancement of nutritional state and stable bone turnover. This data showed a positive relationship between BMD and nutritional change with chlorella treatment, and suggested that chlorella dietary may lead to improving and preventing rapid loss of BMD in postmenopausal women.

• Journal of Nutrition and Health
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• 제22권6호
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• pp.485-496
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• 1989

This study was performed to investigate nutritional effect of various dietary fibers on lead absorption and metabolism of protein and lipid in growing rats. Forty eight male rats of Sprague-Dawley strain weighing 75.7$\pm$0.7g were blocked into six groups according to body weight and fed six kinds of diet different with fiber source(non-fiber, cellulose, pectin) and lead level(0%, 1% ) for 4 weeks. Results are summerized as follows: 1) Food intake, weight gain, FER and PER were remarkably decreased in lead(Pb) added groups, and FER and PER in Pb-added pectin group were significantly lower than those in Pb-added non-fiber group. 2) Weight of liver, kidney and epididymal fat pad, bone weight and length, hematocrit, and hemoglobin content were decreased in Pb-added groups. 3) Total protein content in serum was tended to be decreased in Pb-added groups, but total lipid and cholesterol contents in serum were not different with dietary Pb level and fiber source. 4) Nitrogen, lipid and cholesterol content in liver were tended to be deceased in Pb-added groups, and especially those of the Pb-added pectin group were the lowest among groups. 5) Daily urinary and fecal excretions of nitrogen, lipid and cholesterol were decreased in Pb-added groups. Especially fecal excretions of nitrogen, lipid and cholesterol in Pb-free groups were significantly increased by dietary cellulose and pectin. 6) Pb content in blood was significantly increased in Pb-added pectin group. There was no significant decrease in Pb contents of liver, kidney and tibia, and increase in excretion of Pb by feeding dietary fibers. In conculsion, dietary fibers had no effect on the absorption of Pb, and dietary pectin seemed to increase Pb poisoning by decreasing bioavailibility of protein, lipid and other nutrients in the diet.

• Journal of Nutrition and Health
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• 제19권5호
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• pp.323-332
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• 1986

This study was performed to see the effects of lead poisoning and dietary protein levels(6, 15 and 40 % casein diets) on growth, protein and lipid metabolisms in growing rats. It was also investigated whether the high protein intake would alleviate lead toxicity by decreasing Pb absorption and/or increasing Pb excretion. The results obtained were summarized as follows ; 1) Weight gain, F.E.R liver weight, weight and length of bone in Pb-administered groups were lower than in Pb-free groups. However, these values in the 40% casein diet group with Pb were increased to the level in 15% casein diet group without Pb. 2) Hematocrt and hemoglobin content in blood were lower in Pb -adminstered groups than in Pb free groups. Especially, these levels were lower in 6% casein diet group with Pb than in any other group. 3) Plasma protein level in th e 40% casein casein diet group was the highest of all groups and those of Pb-administered groups tended to be lower than those of Pb-free groups. Plasma lipid and cholesterol levels were increased with decreasing dietary protein level, and these levels were higher in the animals exposed to Pb than in free groups.4) Total liver protein, lipid and cholesterol contents were increased with increasing dietary protein level, and these contents were lower in Pb-administered groups than in Pb free groups. 5) Fecal Pb excretion was not different between 6 and 40% casein diet groups. However, urinary Pb excretion was higher in the 40% casein diet group than in the 6% casein diet group. Above results suggest that, in exposing to the Pb pollution, sufficient protien intake must be recommended. High protein intake seemed to alleviate lead toxicity by increasing urinary Pb excretion.