• Restorative Dentistry and Endodontics
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• 제25권3호
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• pp.435-445
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• 2000

The purpose of this study was to compare the leakage of four different obturation techniques in conjunction with immediate apical barrier of ${\beta}$-tricalcium phosphate(TCP) in teeth with open apex. Eighty single-rooted human premolar teeth were prepared and sectioned horizontally, so maximum diameter in apex was 4mm. Apical defects that were similar to open apex, were created with #1/2 round bur and SF104R bur. The apical foramen were opened to a size 80 file extended 3mm beyond the apex. The teeth were placed into the oasis block soaked saline to simulate periapical tissue often associated with pulpless teeth and received apical barriers consisting of TCP followed by obturation using lateral condensation technique, vertical condensation technique, continuous wave technique and thermoplasticized gutta-percha injection technique. Two unobturated teeth served as positive and negative controls. Teeth were immersed in resorcinol-formaldehyde resin for S days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5mm(level 1), 2.5mm(level 2) and 3.5mm(level 3) from the apex, and examined under a stereomicroscope at ${\times}40$ magnification. The photographs were taken at ${\times}40$ magnification of the filling in each level and scanned. The leakage length in tooth/resin interface was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the leakage length of canal wall infiltrated with resin to the total length of the canal and was analyzed statistically(One-way ANOVA and Scheffe test). The result were as follows : 1. At the level 1, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), and the most leakage in the continuous wave technique group(group 3). There was statistically significant difference between the thermoplasticized gutta-percha injection technique group and the continuous wave technique group(p<0.05). 3. At the level 3, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there were no statistically significant differences between other groups(p>0.05). These results suggest that thermoplasticized gutta-percha injection technique which had 1mm apical gutta-percha matrix after the formation of TCP apical barrier, can demonstrate favorable apical sealing.

• 대한수의학회지
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• 제54권3호
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• pp.179-184
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• 2014

This study investigated the anatomy of the nutrient foramen (NF) in German Shepherds by recording the number, site, position, and direction of penetration of the nutrient canal (NC) in the humerus, radius, and ulna of 50 individuals. The site index of the nutrient foramen (SI) was calculated as the ratio of the length to the NF site from the proximal end to the greatest length of the bone. The NF diameter was measured using different sized needles. Most humeri had only one NF on the caudal surface, particularly on the lateral supracondylar crest, or distal cranial surface. All radii had one NF, usually on the caudal surface, while most ulnae had one NF located on either the cranial or lateral surfaces. The SI and NF diameters were 58.0~59.5% and 0.73~0.78 mm in the humerus, 30.4~30.9% and 0.74~0.76 mm in the radius, and 29.3~29.8% and 0.67~0.68 mm in the ulna, respectively. With the exception of the relatively proximal NF of the radius, the direction of penetration followed Berard's rule. This study provides novel information on the location and diameter of the NF and direction of the NC in the long bones of the pectoral limb of German Shepherds.

• 한국수산과학회지
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• 제55권2호
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• pp.189-194
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• 2022

Unidentified postflexion larva (18.57 mm in standard length, SL), belonging to the family Synodontidae was collected from Jeju Island, Korea, in November 2019. Molecular analysis revealed that the unidentified larva was identical to Synodus kaianus adults in mtDNA cytochrome c oxidase subunit I region (Kimura-2-parameter distance, d= 0.006), and was different from the close species S. macrops (d=0.220). The postflexion larva of S. kaianus has the following morphological features: regularly distributed seven peritoneal pigment spots along the alimentary canal; and, intensively distributed stellate melanophores at the middle of the base of caudal fin and behind the last anal fin ray. The postflexion larva of S. kaianus differed from that of S. macrops in snout length and size of peritoneal pigment spots. This is the first record of S. kaianus in Korea, and we suggest the Korean name "Ka-i-ya-kkoch-dong-myeol" for S. kaianus, according to Lee et al. (1999).

• Journal of Korean Neurosurgical Society
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• 제61권6호
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• pp.707-715
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• 2018

Objective : To investigate the potential risk of approach-related complications at different access angles in minimally invasive lateral lumbar interbody fusion. Methods : Eighty-six axial magnetic resonance images were obtained to analyze the risk of approach-related complications. The access corridor were simulated at different access angles and the potential risk of neurovascular structure injury was evaluated when the access corridor touching or overlapping the corresponding structures at each angle. Furthermore, the safe corridor length was measured when the corridor width was 18 and 22 mm. Results : When access angle was $0^{\circ}$, the potential risk of ipsilateral nerve roots injury was 54.7% at L4-L5. When access angle was $45^{\circ}$, the potential risk of abdominal aorta, contralateral nerve roots or central canal injury at L4-L5 was 79.1%, 74.4%, and 30.2%, respectively. The length of the 18 mm-wide access corridor was largest at $0^{\circ}$ and it could reach 44.5 mm at L3-L4 and 46.4 mm at L4-L5. While the length of the 22 mm-wide access corridor was 42.3 mm at L3-L4 and 44.1 mm at L4-L5 at $0^{\circ}$. Conclusion : Changes in the access angle would not only affect the ipsilateral neurovascular structures, but also might adversely influence the contralateral neural elements. It should be also noted to surgeons that alteration of the access angle changed the corridor length.

• Restorative Dentistry and Endodontics
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• 제8권1호
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• pp.123-131
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• 1982

The purpose of this study was to observe the responses of the remaining pulp tissue after pulpotomy upon the several kinds of $Ca(OH)_2$ products and the responses of periapical tissue upon some root canal filling materials after extirpation. For pulpotomy, the class V cavities were prepared on the premolars, molars and upper canines, and the pulp was amputated. Each drug was placed over the amputated tissue and cavity was sealed with zinc oxide eugenol cement. The drugs which were used for the study were Dycal (Caulk Co. U.S.A.), Cavitec (Kerr Co. U.S.A.), Calvital, Nobudyne and Neodyne (Neo Dental Chemical Products). For extirpation, the endodontic cavities were prepared on the lingual surfaces of anterior teeth, and the pulp tissues were extirpated as routine method. After enlarging, irrigation, and measuring of root length by taking X-ray, each root canal filling material was filled in the canal with gutta percha cone, and endodontic cavity was sealed with zinc oxide eugenol cement. Zinc oxide eugenol, $Ca(OH)_2$ (Eli Lilly Co. U.S.A.) and Vitapex (Neo Dental Chemical Products) were used as root canal filling materials. Animals were sacrificed after 1, 3 and 6 weeks following the operation. The teeth were decalcified in formic acid, sectioned and stained with hematoxylin eosin. Microscopic examination revealed as follows. 1. Dycal: The dentin bridge formation was observed at the 3rd week after pulpotomy. Inflammatory conditions which were infiltration of inflammatory cells and dilatation of blood vessels were kept in remaining pulp tissue at the 6th week. 2. Calvital: The dentin bridge was observed at the 1st week after pulpotomy. As the time clasped, the pulp tended to be the fibrous degeneration. 3. Cavitec, Nobudyne and Neodyne: In the case of Cavitec and Nobudyne, the incompleted and irregular dentin bridge was observed at the 6th week, and in Neodyne, was observed at the 3rd week. The severe inflammatory changes were seen in the remaining pulp tissue. As the time clasped, the fibrous degeneration tended to spread in the remaining pulp tissue. 4. $Ca(OH)_2$: Osteocementum was formed at the 3rd week, the matrix of cementum and dentin were resorted, and infiltration of lymphocytes was seen in periapical tissue when $Ca(OH)_2$ was used as canal-filling materials. S. ZOE and Vitapex The cementum like substance was seen in periapical portion at the 1st week, when ZOE and Vitapex were used as root canal filling materials. As the time elapsed, the matrix of cementum and dentin tended to be resorted. At the 6th week, the inflammatory condition of periapical tissue was continued in the case of ZOE, but was reduced in the case of Vitapex.

• 한국정밀공학회지
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• 제23권11호
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• pp.126-134
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• 2006

In this study, the effect of stem-end design on contact pressure and stress distribution in revision TKR was investigated using finite element method. The finite element model of tibia, including the cortical bone, the cancellous bone and canal, was developed based on CT images. The implant models with various stem lengths, diameters, friction coefficients, and press-fit effects were considered. The results showed that the longer stem length, the stronger press-fit, the bigger stem diameter, and the higher friction coefficient increased both peak contact pressure and Von-Mises stress distributions. The results supported the clinical hypothesis that peak contact pressure and stress are related to the stem end pain. The results of this study will be useful to design the stem and reduce the end-of-stem pain in revision TKR.

• 대한치과의사협회지
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• 제54권8호
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• pp.658-665
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• 2016

Treatment of immature permanent teeth with irreversibly damaged pulp has been challenging in dental practice because of the lack of apical constriction, thin dentinal walls, and short roots. This may lead to the extrusion of filling materials, and fracture of the root due to its more fragile feature during shaping of the root canal. Apexification with calcium hydroxide or MTA is one of the treatment options for these cases. Although favorable results of apexification have been reported, these treatment procedures do not guarantee the increase of root length and/or width even after a long term period. Thus, treated teeth are still prone to fractures. Recently, pulp revascularization has been proposed as an alternative treatment for immature teeth with necrotic pulp and periapical pathosis. Pulp revascularization allows the stimulation of the apical development and the root maturation. There have been many treatment protocols using various materials such as antibiotics and calcium hydroxide medicament. In this case report, literature review about pulp revascularization and two related cases are presented.

• 한국임상수의학회지
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• 제15권2호
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• pp.263-266
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• 1998

외이도의 직경 및 길이와 외이도 질환과의 연관성을 알아보고자 73두 성견을 실 험에 이웅하였다. 임상중상, 배양 및 도말 검사를 통하여 외이 질환이 얼는 정상군 57개의 이 관과, 질환이 있는 비정상군 89개의 이관에 직경과 길이를 평가하기 위한 간접적인 방법으로 이관내 조영술을 실시하였다. 비정상군은 정상군에 비하여 윤상연골 및 귓바퀴 연골의 직경 이 더 넓었다. 수직외이도를 구성하는 귓바퀴 연골의 길이는 비정상군4(12.79{\pm} 3.08)이 정상 군(12.79{\pm}5.87 mm)$에서 보다 유의성 있게 길게 나타났다(p<0.001). 심한 외이도 협착증을 보이는 21개의 귀에서는 외이도 질환을 발견할 수 없었으며, 외이도 질환이 심한 귀에 있어 서 그 직경과 길이가 정상군에 비하여 넝고 길게 나타났다(p<0.05). 본 실험의 결과로 보아 외이도관의 협착증과 외이도 질환과는 연관성이 발견되지 않았으나, 환기와 귀내 분비물의 배출을 방해하는 긴 수직외이도를 갖는 귀가 외이도 질환과 밀접한 관계가 있는 것으로 생각 되었다.

• 대한치과의사협회지
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• 제14권5호
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• pp.457-459
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• 1976

The author experienced a failed ase of root resection which qas performed on the abnormal upper right lateral incisor. The patient was 16year old female. Clinically the effected tooth had neither a carious cavity nor periondontal diseases, ut, a fistula was present on the gum tissue near the root apex. The roentogenogram revealed a pathological area around the apex of the tooth. The results of failed apicoectomy lead to following conclusions. 1. The operated tooth was a case of dense invaginatus which had two pulp cavities and two canals seperated along their entire length. 2. It was the main cause of failure that the second pulp cavity and root canal were not obturated.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.168-172
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• 2009

Shihmen reservoir was started in May 1963. The main purposes of Shihmen reservoir are for agriculture, power supply, flood control and tourism. Shihme Asn dam is an earth dam. Its crown height is 133m above mean sea level, with length 360 m, watershed 763.4 km², and maximum volume 309 million cms. Turbidity in Shihmen dam was severely affected by typhoons Aere (2004) and Masa (2005). Increased deposition after Aere was 28 million cms. Turbidity at Shihmen Canal Inlet is 3000 NTU (Nephelometry Turbidity Unit). Sediment sluicing strategies for downstream channel are demanded. Therefore, diversionary sediment preventing channel is planned in the upstream of Shihmen reservoir. Finally, turbid flow in tunnel channel is bypassed and diverted its flow down to downstream.