레진강화형 글라스아이오노머의 2 축 굽힘강도

이용근,임미경,구대회,이정식 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

Resin-modified glass ionomers were introduced in 1988 to overcome the problems of moisture sensitivity and low early mechanical strengths of the conventional glass ionomers, and to maintain their clinical advantages. The purpose of this study was to evaluate the bi-axial fracture strength of four resin-modified glass-ionomers(Fuji II LC, Vitremer, Dyract, VstiGlass), one resin composite material(Z-100), and one conventional glass-ionomer(Fuji II). Three specimens of each material and shade combination were made according to the manufacturers' instructions. Materials were condensed into metal mold with a diameter of 10mm and a thickness of 2.0mm and pressed between two glass plates. Resin-modified glass ionomers were polymerized using a Visilux II light curing unit by irradiating for 60 seconds from both sides, and conventional glass ionomer was cured chemically. After specimens were removed from the molds, surfaces were polished sequentially on wet sandpapers up to No. 699 silicone carbide paper. The specimens were thermocycled for 2,000 cycles between 5℃ and 55℃ distilled water. After thermocycling, bi-axial fracture strengths were measured using a compressive-tensile tester(Zwick 1456 Z020, Germany) with the cross head speed of 0.5mm/minute. The results were as follows: 1. Two factors of the kind and color of materials had a main effect on bi-axial fracture strength (p<0.01), and bi-axial fracture strength was influenced significantly by the kinds of materials (p<0.01). But there was no significant interaction between two variables of the kind and color of materials (p>0.05). 2. Comparing the mechanical properties of the materials, the elastic modulus of Z100 was higher than any other material, and there was no difference in the displacement at fracture among materials. The bi-axial fracture strength of Z100 was significantly higher than any other material, and that of resin-modified glass ionomers was significantly higher than that of conventional glass ionomer (p<0.05). 3. In the same material group, the color of material had little influence on the mechanical properties.

ISONIAZID 대량투여에 의한 백서간의 조직 병리학적 연구

이충식 충남대학교 의과대학 지역사회의학연구소 1980 충남의대잡지 Vol.7 No.2

Isoniazid, a widely used antituberculous drug, were oxidized by cytochrome p450 enzymes in human and rat liver microsomes to highly reactive acylating and alkylating agents, and this process were potentiated by pretreatment with phenobarbital. To evaluate the histopathological changes for the influences of isoniazid treatment and phenobarbital pretreatment, each intraperitoneal injections of physiologic saline solution, 100mg of phenobarbital, or 200mg of phenobarbital were given to male albino rats, and then each 500mg/kg of isoniazid in physiologic saline solution also were given intraperitoneally. The results obtained were as follows: 1. The mortality in isoniazid only treated rats was 0%, in phenobarbital 100mg pretretaed rats was 0%, and in phenobarbital 200mg pretreated rats was 25%. 2. The hepatic cellular necrosis in isoniazid only treated rats was mild on-the 2nd day of experiment, whereas phenobarbital 100mg pretreated rats was mild on the 3rd day and moderately progressed on the 6th day. The phenobarbital 200mg pretreated rats revealed moderate necrotic change after the 2nd day of experiment. 3. On reticular staining, derangement of reticular fibers in isoniazid only treated rats was also mild on the 2nd day of experiment. The phenobarbital 100mg pretreated rats were noted mildly on the 3rd day of experiment, but intensively changed after the 5th day, compared with marked irregularity after the 2nd day in 200mg pretreated rats.

Lead Germanate 단결정의 초음파 감쇠

이수대,채건식,김영국,설정식 慶南大學校 附設 基礎科學硏究所 1989 硏究論文集 Vol.1 No.-

The temperature dependence of the ultrasonic velocity of 10 MHz and the absorption coefficient in the 10-30MHz range by the pulse echo method were determined in lead germanate single crystal. The velocity of longitudinal 10 MHz ultrasound along the c axis changed anomalously at the phase transition point and the jump was approximately 50m/sec. Near Curie point, the relaxation time and the kinetic coefficient of electric polarization from the Landau-Khalatnikov theory were calculated as ?? sec and ??, respectively. At room temperature, the viscosity tensor were measured as, ?? in the MKS units.

한국 재원 정신분열병환자의 사회경제적 특성에 관한 역학적 조사 : 일일 시정조사 Point Prevalence Study

정인원,김용식,이정균 大韓神經精神醫學會 1985 신경정신의학 Vol.24 No.1

1984년 2월 27일 현재 전국 정신과 병·의원의 입원환자를 대상으로 일일시정조사를 시행하였다. 자료분석 때까지 도착한 자료중 ICD-9의 진단기준에 의하여 정신질환의 범주에 속하는 2,895명을 1:1 쌍쌍대응법으로 분석하여 거주지별로 정신분열병군과 대조군간의 사회경제적 특성을 비교하였다. 분석결과는 다음과 같았다. 1. 정신분열병환자의 결혼상태는 두 지역 모두에서 독신이 많았고 odd ratio는 각각 5.33과 3.56이었다. 농ㆍ어촌의 정신분열병환자가 독신이 더 많았다. 2. 교육수준은 양 군에서 뚜렷한 차이는 없었다. 3. 직업은 도시의 정신분열병환자에서 무직이 많았고 odd ratio는 1.90이었다. 4. 경제수준은 도시의 정신분열병환자에서 낮은 층이 많았고 odd ratio는 1.65이었다. 5. 그외 가족구조와 종교, 부모의 결혼상태에서는 유의한 차이를 보이지 않았다. Aiming at suggestion the possible ways to improve psychiatric care, rehabilitation, and mental health services in Korea, this nation-wide hospital study was intended to explore the socioeconomical status of mental in-patients. This point prevalence study was conducted to patients who were in psychiatric wards at Feb. 27th. 1984 using mailing questionnaire. The number of hospitals and clinics answered was 88 and the patients, 3,300. Among them, we selected the 2,895 patients who were included in mental disorders (290-319) by ICD-9. Finally we compared the socioeconomical status between schizophrenia and non-schizophrenia in rural and urban area with the method of Fleiss. The results were as follows; 1. The relative proportions of single persons in schizophrenia were higher in both areas, and their odds ratios were 5.33 and 3.56, respectively. There were more single schizophrenics in rural than urban. 2. In educational levels, there were no significant differences between schizophrenia and control. 3. In urban area, the jobless persons were more in schizophrenia than control, and its odd ratio was 1.90. 4. The urban schizophrenics were significantly lower than the urban control in economical levels, and its odd ratio was 1.65. 5. About family structure, religion, and marital status of parents, there were no significant differences between schizophrenia and control.

Disilver Cadmium Tetraiodide Membrane Electrode에 관한 연구

李根植,金禎姬 淑明女子大學校 1978 論文集 Vol.18 No.-

This experiment is concerned with determining the sensitivity, stability and reproducibility of Ag_2CdI_4 membrane electrode, the response of the electrode to Cd^2+ concentration, and the effect of inhibitor and pH of the solution. The ion-sensitive membrane electrode is prepared by mixing Ag_2CdI_4 with PVC power in 4 to 1 rato and pressing with IR pellet press. The observations may be summarized as follows: 1. The potential plot is linear with the slope of 27.0mV in the range of Cd^2+ conce ntration 1×10^-1M∼1×10^-5M, slightly deviated from the Nernstian value, but the stability and reproducibility of the electrode is quite acceptable. 2. The electrode is considered to be applicable in the pH range of 2∼9. 3. The electrode shows no definite sensitivity to any other cations or anions except Ag^+ and Hg^2+. 4. Using the electrode as indicator electrode, Cd^2+ solution is titrated with 0.1M NaOH standard solution by precipitation titration and EDTA complexometry.

過量의 鹽分攝取가 白鼠腎臟 動脈에 미치는 影響에 對한 病理學的 硏究

李忠植,姜大榮 충남대학교 의과대학 지역사회의학연구소 1984 충남의대잡지 Vol.11 No.1

There are considerable data which indicate that the high salt intake is important or necessary to the development of hypertension in man and animals, and the low-salt diet is effective lowering the blood pressure. This study is made to evaluate the morphologic changes of small arteries on high-salt diet and salt-restrction in rats. Male albino rats were fed different amount of salt (0.06;%, 0.4%, 4. 0%, 8.0% of NaCI) for 2-20 weeks and changes of arterial calibers of different sized arteries are studied. The results were as follows: 1. In salt-fed groups, the arterial walls reveal medial thickening due to hyperplasia of smoo muscle cells, especially in medium-(4.0%) and high-salt(8.0%) groups. 2. There is no significant differences of external-to-luminal diameter(ED/LD among three rena arterial types with each experimental group(p>0.1). 3. In salt-fed groups, increment of ED/LD ratio in comparison to the control group is significant in all arterial types of medium-and high-salt groups (p<0.01), but insignificant in low-salt(0.4%) group (p>0.05). 4. Restriction of salt intake after 10 weeks salt feeding did not reverse altered ED/LD ratio in all arterial types (p>0.05). In summary, the results obtained by present study indicate that intake of a large amount of salts bring about hyperplastic thickening of the wall of renal arterial system with comparative narrowing of the lumen, and that these changes persist even after the restrictction of salt intake.

상아 소구치 근관치료후 수복방법에 따른 응력분포의 유한 요소 분석

이재영,이정식,조효선 大韓齒科保存學會 1996 Restorative Dentistry & Endodontics Vol.21 No.1

Eugenol, Capsaicin 과 Demethoxy - NE가 치수동통 반응에 미치는 영향

이은구,이정식 大韓齒科保存學會 1992 Restorative Dentistry & Endodontics Vol.17 No.1

The purpose of this study was to invesigate the analgesic effect of eugenol, capsaicin and demethoxy-NE. Young about cats, weighing 2.0 to 3.0kg, were used. Each animal was anesthetized (α-chloralose 60mg per kg body weight) and divided into four groups; control, eugenol, capsaicin and demethoxy-NE group. The anterior digastric muscles were exposed and a pair of electrodes was inserted to record the electromyograms. To expose the pulp, each canine teeth was prepared with a low speed bur under cooling and used for recording anterior digastric muscular EMGs evoked by noxious stimulation of dental pulp. To observe effects on jaw opening reflex, inferior alveolar nerve of both sides were exposed for drug application and wire electrodes were inserted in anterior digstric muscle for recording the EMGs. To observe effects on action potential, saphenous nerves of both sides were exposed and three tissue pools were made from surrounding tissue. The most distal pool was used for applying stimulation, the most proximal one for recording of action potential, and the other one for drug application. One side of inferior alveolar nerve and saphenous nerve were used for eugenol, capsaicin, or demethoxy-NE application, the other side of nerve for control experiments(only vehicle application). Anterior digastric muscular EMGs evoked by noxious stimulation of dental pulp were recorded before drug application, immediate after drug application, at 60 and 120 minutes, and 5 days after drug application. Action potentials were recorded before application, immediate after 30 minutes drug application, at 30, 60 and 120 minutes after drug had been washed out. The results were as follows; 1. Eugenol had a continuous blocking effect on the anterior digastric muscular EMGs evoked by noxious pulp stimulation and after 5 days, showed completely blocking effect. 2. After 5 days, demethoxy-NE applied to dental pulp had a considerable blocking effect on the jaw opening refex evoked by noxious stimulation but capsajcin had no significant effect. 3. After 5 days, eugenol group showed the strongest blocking effect among the all experimental groups on the jaw opening reflex evoked by noxious stimulation of dental pulp and capsaicin group showed the weakest blocking effect. 4. Eugenol had a completely blocking effect on the action potential conductivity of peripheral nerve. Capsaicin and demethoxy-NE had the blocking effect on the action potential conductivity of Aδ and C-nerve fibers. 5. Capsaicin, demethoxy-NE and eugenol applied to inferior alveolar nerve surppressed the jaw opening reflex evoked by noxious stimulation of dental pulp.

근관 충전용 Sealer가 수종의 세포에 미치는 독성효과에 관한 연구

이정식,임미경 大韓齒科保存學會 1992 Restorative Dentistry & Endodontics Vol.17 No.2

This study was performed to evaluate and compare the cytotoxic effects of five root canal sealers to several cifferent cell lines. Five root canal sealers were AH-26, N2, Sealapex, Tubliseal, and Vitapex. Each esalers were mixed according to the manufacturer's instructions and culture media were added to each sealers immdeiately after mixing (the immediate group) and after three days (the third day group) and seven days (the seventh day group) respectively. And every sealer solutions were diluted to 1:1, 1:2, 1:3 and 1:4. Three different permanent cell lines (HEp-2, McCoy, MRC-5) and human gingival fibroblasts and mononuclear cells were challenged by each sealer solution and the cytopathic effects were evaluated using MTT-ELISA MTT-microscopy, and lactate dehydrogenase(LD)activity. The results were as follows: 1. In Ep-2 and MRC-5 cells, Vitapex was the least cytotoxic sealers. 2. AH-26 showed mild cytotoxic effects to HEp-2, gingival fibroblast and mononuclear cells. 3. N2 was the most toxic xealer to gingival gibroblast and it showed relatively strong cytotoxicity to HEp2, McCoy, MRC-5 cells. 4. Tublisdal showde strong cytotoxic effects to HEp2, McCoy, MRC-5, and mononuclear cells. 5. Sealapex showed strong cytotoxic effects to HEp2, McCoy, MRC-5, and gingival fibroblasts.

분광광도계를 이용한 커피와 인공타액에서의 수복용 복합레진의 변색에

이정식,조효선,엄승희 大韓齒科保存學會 1996 Restorative Dentistry & Endodontics Vol.21 No.2