변연골 흡수가 내측연결 임플란트 매식체의 응력분포에 미치는 영향

윤미정,윤민철,엄태관,허중보,정창모 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.2

Purpose: The change of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. The purpose of this study was to investigate the load transfer of internal conical joint type implant according to marginal bone resorption by using the three-dimensional finite element analysis model. Materials and methods: The internal conical joint type system was selected as an experimental model. Finite element models of bone/implant/prosthesis complex were constructed. A load of 300 N was applied vertically beside 3 mm of implant axis. Results: The pattern of stress distribution according to marginal bone resorption was similar. The maximum equivalent stress of implant was increase according to marginal bone resorption and the largest maximum equivalent stress was shown at model of 1 mm marginal bone resorption. Although marginal bone loss more than 1mm was occurred increasing of stress, the width of the stress increase was decreasing. Conclusion: According to these results, the exposure of thin neck portion of internal conical joint type implant is most important factor in stress increasing. 연구 목적: 지금까지 성공적인 임플란트 치료를 위해 많은 연구가 진행되어 왔으며, 임플란트 주변 골 흡수 현상에 대한 연구는 매우 관심이 높은 분야 중 하나이다. 이에 본 연구에서는 삼차원 유한요소응력분석을 이용하여 변연골 흡수가 내측연결 임플란트 매식체의 기계적 안정성에 미치는 영향을 간접적으로 확인하고자 하였다. 연구 재료 및 방법: 악골에 식립된 내측연결 형태의 임플란트 매식체에 티타늄 소재의 임플란트 지대주를 지대주 나사로 연결하고 상부에 금합금관을 장착하는 삼차원 유한요소모형을 설계하였다. 0, 1, 2, 3 mm의 변연골 흡수 상태를 적용하고, 교합면 중심에서부터 3 mm 편측에 300 N의 수직 하중을 가하여 임플란트 매식체에 발생하는 최대 주응력을 계산하였다. 결과: 유한요소분석결과 변연골 흡수에 따른 임플란트 매식체의 최대 주응력 분포는 유사한 양상을 보였으며, 임플란트 매식체 상단에서 가장 높은 응력 집중이 나타났다. 최대 주응력은 처음 1 mm 변연골 흡수를 가정하였을 때 가장 크게 증가하였고, 이후 변연골 흡수가 증가할수록 응력은 증가하였지만 응력 증가의 폭은 감소하는 경향을 보였다. 결론: 이러한 결과로부터 내측연결 임플란트에서 매식체 두께가 얇은 경부의 노출은 변연골 흡수로 인한 응력 증가에 가장 큰 원인임을 알 수 있었으며, 매식체의 변형, 균열 및 파절 등의 기계적 실패를 감소시키기 위해서는 이에 대한 외과적, 보철적 고려가 필요할 것으로 생각된다.

가축분뇨 처리방법별 비용과 규모의 경제성

허덕,정민국 한국농업정책학회, 한국축산경영학회 2001 농업경영정책연구 Vol.28 No.2

The objectives of this study were to analyze the cost and return to the scale of livestock manure management facilities and suggest the optimal scale of livestock manure management for minimizing livestock manure management costs. The data for this study were obtained from farm survey concerning livestock manure management cost. Major findings and policy implication drawn by the analyses are summarized as follows: for pig and hanwoo raising, according to the increase of the equipment scale, the cost of livestock manure management per head does not decrease and for dairy, according to the increase of the equipment scale, the cost of livestock manure management per head decrease. therefore the unit price of government supports should be changed for dairy.

다발성 연조직 종괴를 동반한 급성 림프구성 백혈병의 증례 보고

장정용,허경회,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.2

A 15-year-old patient, who had been diagnosed and treated as Burkitt cell type acute lymphoblastic leukemia (ALLL3) already, visited our department. He complained of gingival enlargement and loosening teeth 1 month ago. The clinical examination revealed anterior open bite, gingival enlargement, and nontender swelling particularly in molar regions of both jaws. Deep periodontal pockets and severe mobility was shown on most of the teeth. The panoramic radiographs showed severe bone destruction and extrusion of the molars. The contrast enhanced CT showed multiple enhanced mass and bone marrow obliteration in both jaws. Chemotherapy was done and the swelling was subsided at 1 month later. In conclusion, radiologic findings of leukemia with soft tissue mass, known as chloroma or granulocytic sarcoma, mimic those of lymphoma, so blood test may be needed for the final diagnosis.

흰민들레 (Taraxacum coreanum) 추출물이 급성 수은 중독된 생쥐의 간에 미치는 효과

정민주,윤중식,허진,노영복,최영복,김종세,이현화 韓國電子顯微鏡學會 2008 Applied microscopy Vol.38 No.1

본 연구는 급성 수은 독성에 대한 민들레의 효과를 알아보기 위하여 시도되었다. 30 g 내외의 생쥐를 대상으로 대조군, 수은(5mg/kg) 투여군, 수은 투여 후 민들레(3 g/kg)를 구강투여 한 후 다시 24, 48, 72, 96시간, 1주일군으로 세분하여 간장 손상 억제 효과를 알아보기 위하여 생화학적 및 조직학적 실험을 실시하였다. 혈액중 aspartate amiotransferase (AST)와 alanine aminotransferase (ALT)의 수치는 민들레 투여군이 수은 투여군보다 감소되었다. 또한 간조직의 SOD와 catalase 활성도 역시 민들레 투여군이 수은 투여군에 비하여 감소하였으나 통계학적 유의성은 없었다. 간 조직의 광학현미경적 관찰에서 심한 조직괴사가 관찰되지만 민들레 투여군에서는 문맥주위의 약간의 괴사와 심한 호중구 침윤현상이 관찰되었다. 전자현미경적 관찰 결과, 간장에서 수은 투여군은 간세포의 핵이 함입되어 불규칙했으며 미토콘드리아와 조면소포체의 수조가 팽대되고, 리보솜의 탈락이 관찰되었다. 민들레 투여군은 핵이 정상적인 상태로 관찰되었고, 전자밀도가 높은 미토콘드리아가 분포되어 있었으며, 리보솜이 부착된 상태로 층판구조를 형성하는 조면소포체가 관찰되었다. 이상의 연구 결과로 보아 민들레가 수은으로 유발된 간손상을 보호하는 효과가 있는 것으로 사료되며 민들레에 대한 다양한 연구가 필요할 것으로 사료된다. Dandelion has been frequently used as a remedy for women’s disease, inflammatory diseases and disorders of the liver and gallbladder. Dandelion extracts water extract, an herbal medication, may have an effect on the activity of hepatic antioxidant enzymes in diabetic rat. This study aims demonstrate the effect of dandelion extracts, one of the natural chelator, on the biochemical and enzyme activity changes in the mouse liver caused by HgCl₂. Mice approximately 30 gm in weight were grouped into the control, mercury chloride-treated, and the dandelion extractstreated after mercury chloride groups. HgCl₂ (5 mg/kg) and dandelion extracts (3 g/kg) were delivered orally. Serum AST and ALT were measured, enzyme activity of liver were examined by spectrophotometer and ultrastructural alteration of liver were examined by light and electron microscopy. Dandelion extracts were decreased the increase of serum AST and ALT level induced by mercury. The catalase activity was decreased in the dandelion extracts group. The activity of SOD was dereased, but did not show significant differences. Mercury chloride-treated hepatic cell were irregular nucleus, enlarged and reduced number of mitochodria, enlarged rough endoplasmic reticulum, loss of ribosomes. Cells treated with dandelion extracts were similar to those of the control group. In conclusion, dandelion extracts may protect the mercury-induced toxicity on Liver.

Neuropeptide γ의 구조 및 생리활성

구희정,서정길,김은희,허민도,정준기,박장수,강신원,박남규 부산대학교 유전공학연구소 1997 분자생물학 연구보 Vol.13 No.-

생리활성을 지닌 신경펩타이드의 구조와 활성간의 관계를 규명하기 위하여 고상법으로 합성한 세종류의 neuropeptide γ(mammalian-,trout- 그리고 goldfish-neuropeptide γ)를 사용하여 연구하였다. Circular dichroism spectra에 의하면 mammalian-,trout- 와 goldfish-neuropeptide γ는 완충액 조건하에 모두 random한 구조를 나타내었다. 중성 및 산성 지질 존재 하에서, mammalian-과 trout- neuropeptide γ는 여전히 random한 구조를 취하였다. 그러나, goldfish-neuropeptide γ는 중성 및 산성지질하에서 부분적으로 α-helix구조를 나타내었다. 장관 수축활성에 있어서는 carp 장관, guinea-pig 회장 그리고 rat십이지장에 대하여 비교하였다. Carp에 대해서는 goldfish-neuropeptide γ= trout- neuropeptide γ>mammalian-neuropeptide γ순으로 활서이 나타났다. 그러나, guinea-pig 회장과 rat십이지장에 대해서 mammalian-neuropeptide γ는 어류 유래성 neuropeptide g들 보다 높은 수축활성을 나타내었다. 이러한 결과들은 neuropeptide γ들이 종-특이적인 활성을 나타낸다는 것을 제시한다. The relationship between structure and biological activity was studied on the three neuropeptides(mammalian-,trout- and goldfish-neuropeptide γ)that were syntheized by the solid-phase method. Circular dichroism spectra showed that mammalian-,trout- and goldfish-neuropeptide γadopted an undered structure in buffer solution. In the presence od neutral and acidic liposomes, mammalian-and trout- neuropeptide γ also took a random structure. However, goldfish-neuropeptide γ took an α-helical structure in acidic liposomes. The intestinal motility response was investigated with carp interstines, guinea-pig ileums and rat duodenums. In case of carp intestine, contractine activity was as follows:goldfish-neuropeptide γ= trout- neuropeptide γ> mammalian-neuropeptide γ. On the other hand, the contracile activity of mammalian-neuropeptide γ was more potent than trout- and goldfish-neuropeptide γ in the guinea-pig ileums and rat duodenums. these results suggest that neuropeptide γs showed the species-specific activity.

극초음속 추진기관 연구를 위한 2차원 초음속 풍동 설계 및 제작

김정용,김형민,허환일 충남대학교 산업기술연구소 2003 산업기술연구논문집 Vol.18 No.1

A 2-D supersonic wind tunnel is designed to simulate supersonic film cooling and combustion test. Based on allowable chamber pressure and Mach 2.5 flow at the test section of ground-based blowdown type supersonic wind tunnel, 2.39 ㎏/s of mass flow rate is calculated. 2-D supersonic nozzle geometry is drawn using MOC(Method of characteristics) and energy losses of flow discharging out of nozzle is discussed. Test section is 32 ㎜ high and 30 ㎜ wide with 20 ㎜ step for transverse secondary film injection, and designed to maintain constant Mach number region for more than 250 ㎜ long. Schlieren visualization will be used to monitor the flow, and pressure taps and thermocouples are placed at constant spacing of 15 ㎜ in the downstream of film injection to measure the incoming flow conditions.

양식 넙치(Paralichthys olivaceus)에서 발생한 랩도바이러스성 질병의 병리조직학적 특징

이남실,강형길,최희정,전세규,박남규,허민도 한국어병학회 2002 한국어병학회지 Vol.15 No.1

2000년 4월경부터 (수온7-13℃) 우리나라 동해안과 남해안 육상 수조에서 사육되던 넙치에서 체색흑화, 복수저류, 비장종대의 육안적 소견을 보이는 질병이 발생하여 대량폐사를 불러왔다. 병리조직학적 소견으로, 비장과 신장의 조혈조직에서 괴사병변이 주로 나타났다. 비장과 신장의 간질조직에서 괴사소가 관찰되었으며, 임파구, 괴사세포의 침윤이 나타났다. 비장 조직의 전자현미경적 관찰에서 변성혈구 내 세포질에서 탄환형의 바이러스 입자가 관찰되었는데 직경과 길이가 각각 약 50nm, 170nm였다. 이상의 결과로 본 질병은 rhabdovirus에 의한 질병으로 판단되었다. On April of 2000 and February of 2001, a disease characterized by darkening, ascites and enlargement of the spleen occurred in flounder, Paralichthys olivaceus, farmed near northern and eastern coasts of Korea. Various degree of necrosis including liquefactive-type was observed mainly in hemopoietic tissue of spleen and kindney. Certain tissue such as branchial soft tissue including epithelium showed a similar necrotic findings. But some tissues such as intentine had several necrotic clusters of wandering cells, being possibly leukocytes. Necrotic evidences of blood cells were evident in various tissues including hemopoietic tissues. Necrobiotic bodies were frequently encountered in blood smear preparations. Bullet type-virious were detected in the spleenic cells. Each virion was about 500 nm in diameter and 170nm in length. From these results, this disease was thought to be a rhabdoviral disease.

누낭비강문합술(Dacryocystorhinostomy)을 이용한 비루관폐쇄 교정술식에 관한 고찰

백경식,강승우,오상윤,이민정,허원실 大韓顎顔面成形再建外科學會 1992 Maxillofacial Plastic Reconstructive Surgery Vol.14 No.4

Epiphora is overflow of tears due to obstruction of lacrimal duct. Dacryocystorhinostomy is the most common procedure to eliminate the epiphora secondary to complete or partial obstruction of the nasolacrimal duct. The procedure is to artificially create passage between lacrimal sac and nasal cavity. Especially, epiphora would be accompany often by nasolacrimal duct obstruction when trauma of ormaxillofacial area lead to nasal fracture, medial wall fracture of orbit. Therefore in this case there are many case to perform dacryocystorhinostomy because probing and tubing is difficult to resolve the epiphora. We performed 4 cases of dacryocystorhinostomy for adult nasolacrimal duct obstruction from May 1991 to October 1991. The results were very satisfactory in all the case. Epipora disappeared in all case.

임플란트 hexagon 높이에 따른 임플란트와 주위 조직의 응력분포 평가

박성재,김주현,김소연,윤미정,고석민,허중보 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.1

PURPOSE. To analyze the stress distribution of the implant and its supporting structures through 3D finite elements analysis for implants with different hexagon heights and to make the assessment of the mechanical stability and the effect of the elements. MATERIALS AND METHODS. Infinite elements modeling with CAD data was designed. The modeling was done as follows; an external connection type ∅4.0 mm×11.5 mm OsstemUSII (Osstem Co., Pusan, Korea) implant system was used, the implant was planted in the mandibular first molar region with appropriate prosthetic restoration, the hexagon (implant fixture’s external connection) height of 0.0, 0.7, 1.2, and 1.5 mm were applied. ABAQUS 6.4 (ABAQUS, Inc., Providence, USA) was used to calculate the stress value. The force distribution via color distribution on each experimental group’s implant fixture and titanium screw was studied based on the equivalent stress (von Mises stress). The maximum stress level of each element (crown, implant screw, implant fixture, cortical bone and cancellous bone) was compared. RESULTS. The hexagonal height of the implant with external connection had an influence on the stress distribution of the fixture, screw and upper prosthesis and the surrounding supporting bone. As the hexagon height increased, the stress was well distributed and there was a decrease in the maximum stress value. If the height of the hexagon reached over 1.2 mm, there was no significant influence on the stress distribution. CONCLUSION. For implants with external connections, a hexagon is vital for stress distribution. As the height of the hexagon increased, the more effective stress distribution was observed. 연구 목적: 본 연구는 hexagon 높이에 따른 임플란트 각 부위와 주위 지지조직의 응력분포를 3차원 유한요소 해석을 통해 평가하여 hexagon 높이가 기계적 안정성에 미치는 영향을 평가하고자 시행되었다. 연구 재료 및 방법: 외측 연결 형태의∅L4.0 mm×11.5 mm USII (Osstem Co., Pusan, Korea) 임플란트 시스템을 이용하여 하악 제 1대구치 부위에 임플란트를 식립하여 보철 수복한 경우를 연구 모델로 가정하고 임플란트 고정체의 외측 연결부인 hexagon의 높이를 각각 0.0 mm, 0.7 mm, 1.2 mm, 1.5 mm로 적용한 CAD data를 유한요소 모형화하였다. ABAQUS 6.4 (ABAQUS Inc., Providence, RI, USA)를 이용하여 산출된 응력 값 중에서 등가응력을 기준으로 각 요소(상부 치관, 지대주 나사, 고정체, 치밀골, 해면골)에서 나타나는 최대 응력 값을 비교 하였다. 결과:외측 연결을 갖는 임플란트의 hexagon의 높이는 고정체, 지대주 나사, 상부 보철물 그리고 주위 지지골에 대해 응력 분산에 영향을 주었다. Hexagon의 높이가 증가할 수록 임플란트의 응력 분산은 더 잘 이루어졌으며, 최대 응력 값의 감소를 보였다. Hexagon의 높이가 1.2 mm 이상이 되면 응력 분포에 더 이상 크게 기여하지 않았다. 결론: 외측연결을 갖는 임플란트에서 hexagon은 응력 분산에 필수적인 요소이며 그 높이가 증가할수록 더욱 효과적인 응력의 분산이 나타났다.

The relationship between radiological features and clinical manifestation and dental expenses of keratocystic odontogenic tumor

Min, Jung-Hyun,Huh, Kyung-Hoe,Heo, Min-Suk,Choi, Soon-Chul,Yi, Won-Jin,Lee, Sam-Sun,Bae, Kwang-Hak,Choi, Jin-Woo Korean Academy of Oral and Maxillofacial Radiology 2013 Imaging Science in Dentistry Vol.43 No.2

Purpose: This study was performed to identify correlations between keratocystic odontogenic tumor (KCOT) data from CT sections, and data on the KCOT clinical manifestation and resulting dental expenses. Materials and Methods: Following local Institutional Review Board (IRB) approval, a seven-years of retrospective study was performed regarding patients with KCOTs treated at the Seoul National University Dental Hospital. A total of 180 KCOT were included in this study. The following information was collected: age, gender, location and size of the lesion, radiological features, surgical treatment provided and dental expenses. Results: There was no significant association between the size of the KCOT and age, gender, and presenting preoperative symptoms. In both jaws, it was unusual to find KCOTs under 10 mm. The correlation between the number of teeth removed and the size of the KCOT in the tooth bearing area was statistically significant in the mandible, whereas in the maxilla, no significant relationship was found. Dental expenses compared with the size of the KCOT were found to be significant in both jaws. Conclusion: The size of KCOT was associated with a significant increase in dental expenses for both jaws and the number of teeth removed from the mandible. These findings emphasize the importance of routine examinations and early detection of lesions, which in turn helps preserving anatomical structures and reducing dental expenses.