• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.72-79
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• 2003

The objective of this in vitro study was to evaluate the efficacy of a Ca(OH)$_2$removal before and after early coronal flaring using different types of instruments. 100 plastic blocks with 30$^{\circ}$artificial curved canals were used in this study and randomly divided into a control group and 4 experimental groups(GG, OS, GT, PT Group) 20 teeth each. The canals were instrumented, and Ca(OH)$_2$was temporary filled into the each canal. Irrigation was peformed with Max-i-Probe 25- 30-gauge probes before and after recapitulation. The results of this study were as follows 1. There were no significant difference among the groups in size of irrigating needle(p<0.05). 2. There was a significant difference between before and after recapitulation regardless size of irrigating needle(p<0.05). 3. Before recapitulation, there was a significant difference between 25- and 30-gauge needle in all groups(P<0.05). 4. After recapitulation, there was a significant difference between 25- and 30-gauge needle in the control group(p<0.05). But there were no significant difference among the experimental groups. It is concluded that the effectiveness of canal irrigation was decided to the depth of irrigating needle into the canal. The effect of canal irrigation tend to facilitate by the early coronal flaring. The recapitulation was the most effective during canal irrigation regardless the size of irrigating needle. Therefore, the recapitulation is a mandatory way to facilitate the effectiveness of canal irrigation during canal enlargement.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.423-427
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• 2001

Objective: This study was prepared to figure out a certain dimension and morphology of the condyle at the central, medial and lateral aspects on MR images of asymptomatic volunteers, which could be comparable with those of the TMD patients' condyle. Materials: Sixty TMJs from 30 asymptomatic volunteers(15 male, 15 female) who had no clinical symptoms and no disc displacement on sagital and coronal view of MRI were served as normal. Method: MR images were taken from the asymptomatic volunteers and the dimension of the anteroposterior length, mediolateral width, height, convexities were measured through the images on the sagittal and coronal sections of mandibular condyle. Then, these data were collected and analyzed. Result: The mean value of anteroposterior length was $8.00{\pm}1.21mm$ at central section and mediolateral length was $21.40{\pm}2.32mm$ on coronal view. The anterior condylar length at medial side was the shortest and the convexity of anterior slop at the lateral side was proved to be the flattest among 3 sections. There were little dimensional and morphological differences at sagittal sections, but the mediolateral width of condyle at coronal section was significantly different between male and female. Conclusion: In sagittal sections, the anterior condyle length was shortest at medial side and the convexity of anterior slop was flattest at lateral side, and there were little dimensional and morphologic differences between male and female. In coronal section, male's condyle was more wider and flatter than female's.

• Journal of Trauma and Injury
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• v.27 no.3
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• pp.57-62
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• 2014

Purpose: A hamate body coronal fracture is well known as a very rare fracture in the carpal bones and is also hard to diagnose in initial stage due to the bone's architecture. We report our experience in treatment of such a fracture, and we present a review of the relevant literatures. Methods: Four patients who experienced hamate body coronal fractures from October 2006 to October 2013 were enrolled in this study. One patient also had an associated Capitate fracture, and two patients had associated dislocations of the $4^{th}$ metacarpal joint. We performed open reduction and mini-screw fixation on the four patients. In addition, a K-wire was fixed for the two patients with dislocations. Results: The average follow-up period was 24.5 months after surgery, and bone union was observed at the $8^{th}$ week after surgery. We confirmed that bone union had been completed for all the patients, and functional tests showed that joint motion was in the normal range without complications. Conclusion: When a patient has consistent pain on the ulnar side of the wrist, a hamate fracture should be suspected. Computer tomography is better than a simple X-ray scan for confirming the diagnosis of a hamate body coronal fracture. An open reduction and mini-screw fixation led to a good result.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.3
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• pp.279-283
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• 2000

Disc displacement, deformation, perforation or osteoarthritis may induce the joint space narrowing. This study was designed to get the normal joint space width which could be used as a standard comparing with damaged joints. Twenty asymptomatic volunteers' MR images were evaluated and coronal images of thirty joints having normal disc position in sagittal and coronal views, were selected. The joint spaces were measured at center, medial and lateral side on the coronal views. In normal joints, the mean joint space was $3.57{\pm}0.63mm$ at center, $2.77{\pm}0.51mm$ at medial and $2.41{\pm}0.41mm$ at lateral side of mandibular condyle. The mean of joint space of male was wider than that of female at center, but not significantly different at medial and lateral side of the condyle.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.37.1-37.1
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• 2009

Solar type II radio burst is regarded as a signature of coronal shock. However its association with coronal mass ejections (CMEs)-driven shock and/or flare blast waves remains controversial. On December 31 2007, SOHO/LASCO and STEREO/COR observed a CME that occurred on the east limb of the Sun. Meanwhile, two type II bursts were observed sequently by KASI/E-Callisto and the Culgoora radio observatory during the CME apparence time. In this study, we estimate kinematics of the two coronal shocks from dynamic spectrum of the multiple type II bursts and compare with the kinematics of the CME derived from the space observations. An origin of the multiple type II bursts is inspected and discussed briefly.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.127.2-127.2
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• 2012

Space weather prediction related to flares and CMEs is an important issue these days. It is, however, hard to estimate magnetic energy of invisible coronal magnetic structure. The virial theorem is one of the ways to determine the magnetic energy. In this study, we performed a series of MHD simulation of an emerging flux tube and apply the virial theorem to the simulation results and derive energetics of coronal structures. We then analyze real observational data on NOAA 11302 to derive the distributions of physical quantities, such as density, temperature, velocity and magnetic field. We also use knowledge form simulation analysis to estimate the magnetic energy of NOAA 11302.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.473-485
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• 2021

Adolescent idiopathic scoliosis (AIS), which is associated with an extensive range of clinical and radiological presentations, is the one of the most challenging spinal disorders. The goals of surgery are to correct the deformity in 3 dimensions and to preserve motion segments while avoiding complications. Despite the ongoing evolution of classification systems and algorithms for the surgical treatment of AIS, there has been considerable debate regarding the selection of an appropriate fusion level in AIS. In addition, there is no consensus regarding the exact description, relationship, and risk factors of coronal decompensation following selective fusion. In this review, we summarize the current concepts of selection of the fusion level for AIS and review the available information about postoperative coronal decompensation.

• Journal of Korean Foot and Ankle Society
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• v.26 no.4
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• pp.157-162
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• 2022

Total ankle arthroplasty has become a viable motion-preserving alternative to ankle arthrodesis, especially in the last two decades. Recent improvements have been achieved in the strength of implant design and surgical technique. Nevertheless, addressing preoperative deformities is essential for successful outcomes of total ankle arthroplasty. Residual malalignment can produce instability and edge loading, causing acceleration of polyethylene wear, followed by osteolysis and an increased risk of revision surgery. Therefore, the accompanying deformities and their correction techniques need to be comprehensively elucidated and understood. In this article, we provide a review of the application of total ankle arthroplasty in arthritis with coronal plane varus and valgus deformities.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.43.2-43.2
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• 2019

Tomography is a method to reconstruct three-dimensional structure of an optically thin object. We can obtain the three-dimensional information by combining a number of projected images at different angles. Solar rotational tomography (SRT) is the tomographic method to estimate the coronal structures using the solar rotation. There are a few practical difficulties in solar coronal observation. One of the most crucial difficulty is handling the blocking area by the occulter or the Sun itself. So we have to use the iterative reconstruction for the SRT which can resolve that problem by using the forward modeling. In this study, we propose an alternative method to reconstruct the solar coronal structure: the filtered backprojection (FBP) algorithm. The FBP algorithm is based on the simple analytic solution. Thus it is easy to understand, and the computing cost is much cheaper than that of the iterative reconstruction. Recently we found a solution for the FBP algorithm to the problem of the blocking area in the solar EUV observations. We introduce how to apply the FBP algorithm to the SRT, and show the initial results of the performance test.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.337-345
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• 1999

The purpose of this study was to compare the shape of root canal after instrumentation with some engine driven NiTi files. Thirty narrow and curved canals(15-35 degree) of mesial canals of extracted human mandibular first molars were divided into three groups. Group 1: After radicular access with Gates Glidden drill, apical shaping using step back method with Flexo file Group 2: After radicular access with Gates Glidden drill, apical shaping with Profile .04 Group 3: Canal shaping with GT file and Profile .04. Using modified Bramante technique, the root was sectioned at 2 mm from apical foramen, height of curvature, 2 mm from canal orifice. Canal centering ratio, amount of transport, amount of dentin removed, shape of canal were measured and statistical analysis is done using SPSS Program V 7.5. The results were as follows: 1. Canal centering ratio of group 3 was the lowest at coronal part, but there was no statistical difference. Centering ratio of group 2 was the lowest at curve part, and there was statistical difference between group 1(P<0.05). Centering ratio of group 2 was the lowest at apical part, but there was no statistic difference. 2. Amount of transport of group 3 was the lowest at coronal part, but there was no statistical difference. Amount of transport of group 2 was the lowest at curve part, and there was statistical difference between group 1(P<0.05). Amount of transport of group 3 was the lowest at apical part, and there was statistical difference between group 1 and group 2, group 1 and group 3(P<0.05). 3. Amount of dentin removed of group 3 was the lowest at coronal part, bur there was no statistical difference. Amount of dentin removed of group 2 was the lowest at curve part, but there was no statistical difference. Amount of dentin removed or group 2 was the lowest at apical part, and there was statistical difference between group 1 and group 2, group 1 and group 3(P<0.05). 4. The shape of the canals after instrumentation varied among the groups. The majority of canals at coronal and curve part for group 1 were round in shape(7 in 10), those at apical part were oval(8 in 10). The majority of canals at coronal part for group 2 were round in shape(7 in 10) and there was no difference in the number of shape at other part. There was no difference in the number of shape at every part for group 3. As above results, NiTi rotary instrumentation showed a trend to remain more centered in the canal than SS file instrumentation. At using NiTi file, coronal shaping with Gates Glidden drill was not statistically different from shaping with GT file. But shaping with GT file showed tapered canals, so it may be said that shaping with GT file is a safe and valuable instrumentation method.