• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.88-95
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• 2010

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals. For the preparation of thirty two curved root canals, Mtwo instruments using "single length"technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan's test. The results were as below; 1. The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05). 2. The deformation and fracture of all instruments used for this study were not experienced. 3. In the degree of changes of the dimension of inner walls of canals, Profile demonstrated the lowest changes of the dimension of inner walls of canals except at the measuring points of the 1 and 2 mm (p < 0.05). However, the ProTaper Universal showed the highest changes of the dimension of inner walls of canals at all measuring points (p < 0.05). 4. In the degree of changes of the dimension of outer walls of canals, Mtwo demonstrated the lowest changse of the dimension of outer walls of canals except at the measuring point of the 1 mm (p < 0.05). However, Profile exhibited the highest changes of the dimension of outer walls of canals at the measuring points of 3 and 4 mm and ProTaper Universal and K3 showed the largest changes of the dimension of outer walls of canals at the measuring points of 1, 2, 6, and 7 mm (p < 0.05). 5. In degree of centering ratio, Profile demonstrated the least centering ratio comparing with the centering ratio shown by other NiTi instruments at the measuring points of 1, 4, 5, and 6 mm. Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time.

• Restorative Dentistry and Endodontics
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• v.47 no.2
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• pp.19.1-19.15
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• 2022

Objectives: The aim of this study was to evaluate and compare the apical constriction (AC) and apical canal morphology of maxillary first and second molars, using micro-computed tomography (micro-CT). Materials and Methods: The anatomical features of 313 root canals from 41 maxillary first molars and 57 maxillary second molars of patients with known age and sex were evaluated using micro-CT, with a resolution of 26.7 ㎛. The factors evaluated were the presence or absence of AC, the morphotypes, bucco-lingual dimension, mesio-distal dimension, and the profile (shape) of AC and the apical root canal. The apical root canal dimensions, location of the apical foramen (AF), AC to AF distance, and presence of accessory canals in the apical 5 mm were also assessed. Descriptive and analytical statistics were used for data evaluation. Results: AC was present in all 313 root canals. Patients' age and sex did not significantly impact either AC or the apical canal dimensions. The most common AC morphotype detected was the traditional (single) constriction (52%), followed by the parallel (29%) morphotype. The mean AC dimensions in maxillary first molars were not significantly different from those in maxillary second molars. Sixty percent of AF were located within 0.5 mm from the anatomic apex. Conclusions: The most common morphotype of AC detected was the traditional constriction. Neither patients' age nor sex had a significant impact on the dimensions of the AC or the apical root canal. The majority of AF (60%) were located within 0.5 mm from the anatomic apex.

• Journal of the Korean housing association
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• v.19 no.2
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• pp.43-54
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• 2008

The aim of the research is to find out the direction of unit-plans in multi-dwellings for the future society. Shinonome Canal Court where residents actually live now are the objects in this study, and the residential floor plan of unit-plans were analyzed to find out the typical types. The analysis was focused on the unit-plans of 5 blocks of Shinonome Canal Court. Space Syntax Theory was used as the analysis method. As the first stage of the analysis, justified graphs were made to find out the characters of unit-plans through the classification of the graphs. Contents of the analysis are as follows: Relationship between classified justified graphs and dimension according to node number. Relationship between classified justified graph patterns and unit-plans. Characters of unit-plans in each blocks. Shinonome Canal Court consists of mainly small scale unit-plans and 30unit-plans are classified. 1LDK, 2LDK, 1LDK+S, 1LDK+f are typical unit-plans which are mainly supplied in the complex. It is noted that the results of the analysis by node, justified graph pattern and dimension are the same. It also presents diverse unit-plans which shows a change in nLDK pattern or add f (foyer), AN (annex), S (service room), Fs (free space) to basic nLDK type. In summary, it demonstrates the possibility of creating new residental floor plans in multi-dwellings.

• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.604-609
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• 2016

Objective : The aim of this study was to compare the clinical and radiological outcomes associated with the use of hydroxyapatite (HA) spacer and allogeneic bone (AB) spacer in laminoplasty. Methods : From January 2006 to July 2014, 79 patients with cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament underwent cervical laminoplasty. The radiologic parameters were obtained from plain radiography and three-dimensional computed tomography. All images were taken before and after surgery. Cervical lordosis, spinal canal dimension, fusion between lamina and spacer, and resorption of spacer were checked. Clinical outcomes were assessed using visual analog scale and Japanese Orthopedic Association. Results : Double-door laminoplasty was performed on 280 levels : 182 in the HA group and 98 in the AB group. The mean follow-up was 23.1 months (range : 4-69 months). Similar fusion rates were found in these groups (p=0.3). The resorption rate between lamina and spacer was lower in the HA group (p<0.001). During the immediate postoperative period, the canal dimension of both groups increased compared with the results in the preoperative period. However, the canal dimension of the AB group decreased over time compared with that of the HA group (p<0.001). Conclusion : Double-door laminoplasty improved the clinical outcomes of both groups. However, the spinal canal dimension in the AB group showed a greater degree of reduction than in the HA group at the final postoperative follow-up. Therefore, we suggest that surgeons consider the use of larger-sized AB spacers in double-door laminoplasties.

• Imaging Science in Dentistry
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• v.33 no.4
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• pp.211-215
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• 2003

Purpose: To assess the radiographic findings of odontogenic cysts showing displacement of the mandibular canal using computed tomographic (CT) and panoramic images. Materials and Methods : CT and panoramic images of 63 odontogenic cysts (27 dentigerous, 16 odontogenic keratocysts, and 20 radicular cysts) were analyzed to evaluate the following parameters: the dimension and shape of the cysts, and the effect of the cysts on the mandibular canal and cortical plates. Results: Of the 63 cysts examined in the study, 35 (55.6%) showed inferior displacement of the mandibular canal and 46 (73.0%) showed perforation of the canal. There were statistically significant differences between CT and panoramic images in depicting displacement and perforation of the mandibular canal. Cortical expansion was seen in 46 cases (73.0%) and cortical perforation in 23 cases (36.5%). The radicular cysts showed cortical expansion and perforation less frequently than the other cyst groups. Conclusion: Large cysts of mandible should be evaluated by multiplanar CT images inorder to detect the mandibular canal and cortical bone involvement.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.187-190
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• 2008

The water quality at the Dongbin Harbor at Pohang city, is getting worse due to the sewage and the wastewater from communities. In this syudy, RMA2 and RMA4, which is two-dimensional depth-averaged finite element numerical model, were employed to simulate the improvement of water quality from inflowing water through an inland canal to be planned connecting Dongbin Harbor and the Hyeongsan River. For the comparative result of the numerical model, both the present condition and the restoration condition (after construction of an inland canal) is simulated. The results of these conditions reasonably simulate a real situation at the Dongbin Harbor. After construction of an inland canal, the water quality at the Dongbin Harbor will be compared to the fresh water quality of the Hyeongsan River at the steady state. Futhermore, The result of simulation will be used to decide the most effective dimension of the canal.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.113-121
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• 2012

The study was carried out to investigate the dimension of irrigation canal, and measure the water flow of those diverted from Kimje main canal in Dongjin irrigation area. The rating curves indicating the relationships between water level and discharge of the lateral canals were induced using the measured data with high regression coefficients of 0.957~0.999 at inlet points and 0.932~0.998 at end points, respectively. And Manning's roughness coefficients were estimated as the ranged from 0.015 to 0.074 at inlet points and 0.056 to 0.089 at end points with rectangular type of concrete open irrigation canals, the Manning's roughness coefficients of the end points were less than those values of the end points, which may be considered as the deposition of the bottom sediments.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.467-472
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• 2016

Successful root canal treatment can be obtained by the removal of microorganisms from the pulpal space of the root canal system through biomechanical technique with instruments and irrigation. Due to the difference in the dimension of the pulpal structure such as thin wall of the root, large portion of chamber, the primary teeth should be considered in a different way of approach. Traditionally, fluids have been dispensed passively into the root canals for improve the cleansing. The use of sodium hypochlorite as an irrigant in root canal treatment is widespread and common, because it meets requirements for the ideal irrigants.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.1_2
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• pp.135-142
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• 1992

This study was performed to define the anatomical position of the mandibular canal and the findings during the sagittal split ramus osteotomy of the mandible. The mandibles of 20 adult Korean were used. The dimension of mandibular canal from the mandibular foramen to the 1st molar was measured at 4 specific coronal-sectional location by CT scan. The results were as follows ; 1. The distance from the mandibular canal to the medial aspect of the buccal cortical plate was greatest($4.5{\pm}1.1mm$) at 2nd molar area and was not significantly greater than at any other section. 2. Buccal cortex was thickest($3.8{\pm}0.9mm$) at 2nd molar and thinnest ($2.5{\pm}0.3mm$) mandibular foramen um 3. The distance from the mandibular canal to the medial aspect of the lingual cortical plate was not significant at any sections. 4. The distance from the mandible canal to the inferior border of mandible was greatest at the mandibular foramen($20.7{\pm}3.9mm$). The canal was located more closely to the inferior border at 1st, 2nd molar area 5. The diameter of the mandibular canal was between $2.5{\pm}0.3mm$ and $2.8{\pm}0.6mm$. 6. The total mandibular thickness was greatest($21.1{\pm}2.6mm$) at 2nd molar area and narrowest($17.2{\pm}3.2mm$) at mandibular foramen area.

• Journal of Korean Neurosurgical Society
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• v.39 no.3
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• pp.188-191
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• 2006

Objective : The purpose of this study is to evaluate the efficacy and necessity of combined anterior approach [discectomy and fusion] and posterior approach[open-door laminoplasty] in the treatment of cervical spondylotic myelopathy. Methods : The authors reviewed 14 cases in whom combined anterior and posterior approach performed for cervical myelopathy due to simultaneous anterior and posterior pathology such as huge central disc herniation with narrow spinal canal between January 2000 and December 2002. Clinical symptoms were evaluated by Japanese Orthopaedic Association [JOA] score and then the cervical curvature, change of spinal canal to vertebral body[SC/VB] ratio and canal widening were measured and compared to the clinical symptoms. Results : The mean JOA score increased from $10.4{\pm}3.1$ preoperatively to $14.8{\pm}1.2$ at the final follow up with a mean recovery rate 66.4%. In all cases, there were not neurologic deterioration. Mild postoperative complications developed in two cases. One patient had a limitation of range of neck motion and the other one showed kyphotic change. Postoperative radiography showed an improvement of body to canal ratios [average $0.70{\pm}0.08$ before surgery to $1.05{\pm}0.12$ after surgery and mainte nance or recovery of cervical lordosis. Canal widening of antero-posterior diameter and dimension after operation is 6.8mm. $116.61mm^2$. Conclusion : Combined anterior and posterior procedure could be helpful in decompression of the spinal cord and good functional recovery in spondylotic myelopathy patients with combined anterior and posterior pathology such as huge disc herniation accompanying narrow spinal canal.