• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.3
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• pp.337-342
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• 2000

Purpose : The purpose of this study was to analyze the lower third facial changes in frontal view after mandibular setback surgery. Materials and Methods : In this study, fifteen subjects(6 males and 9 females) with class III dental and skeletal malocclusions who were treated with BSSRO(Bilateral Sagittal Split Ramus Ostetomy) were used. Frontal cephalometric radiographs were taken preoperatively and more than 6 months postoperatively, and hard tissue(H2-Hl) and soft tissue changes (S2-S1) were measured on vertical and horizontal reference lines. In 15 cases, changes which developed more than 6 months after surgery were studied. Results : The results were as follows. 1. In the facial height, hard tissue $decreased(2.46{\pm}2.76mm)$ with statistical significance(P<0.01), and soft tissue also $decreased(1.64{\pm}3.66mm)$. As a result, the facial height generally becomes shorter after sagittal split ramus osteotomy. 2. In the mandibular width, hard tissue $decreased(2.08{\pm}3.59mm)$ with statistical sgnificance(P<0.05), but soft tissue $increased (2.14{\pm}5.73mm)$ without statistically significant difference(P>0.05) postoperatively. 3. In the facial index, hard tissue $decreased(0.23{\pm}2.21%)$, but soft tissue $increased(2.41{\pm}3.46%)$ with statistical significance. Conclusion : One of the main purpose of orthognathic surgery is to achieve facial esthetics and harmony. In order to fullfill this purpose, it is important to carry out a precise presurgical treatment planning by estimating the changes of frontal profile after surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.87-108
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• 1996

This study was intended to perform cephalometric analysis of the facial soft tissue profile after surgical correction of skeletal Class III malocclusion after SSRO in 29 patients (Males 12, females 17). Lateral cephalograms were taken in centric occlusion before and immediate, long term after surgeries. 1. Counter-clockwise rotation of mandible was observed after the surgery, average relapses of mandibular set back were 1.23-1.28mm. The net effects of the mandibular set-back after surgeries were 81.7-82.2%. Because these relapse tendencies may reduce the effects of the surgical outcomes, surgeon must consider these net before the surgical treatment planning. 2. The ratio of horizontal changes of hard tissue to soft tissue at lower lip, mentolabial sulcus, pogonion were 72.7-93.7%, 100.3%, 99.1-102.1% respectively. There were little changes at upper lip position anteroposteriorly. 3. The relationship of upper and lower lips were improved after surgery. Lower lip was posteriorly repostioned and upper lip was flattend and elongated in conjunction with deepening of inferior lobial sulcus. But profile of chin was still prominent after surgery. 4. Hard tissue horizontal changes and tissue vertical changes were significantly correlated with each other and there were reverse correlations with hard tissue vertical changes and soft tissue horizontal changes.

• The korean journal of orthodontics
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• v.35 no.2 s.109
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• pp.91-105
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• 2005

For af accurate diagnosis and treatment planning of facial asymmetry, the use of 3-dimensional (3-D) image is indispensable. The purpose of this study was to get standard data for the 3-D analysis of facial asymmetry Computerized tomography (CT) was taken in the 60 normal occlusion individuals (30 male. 30 female) who did not have any apparent facial asymmetry. The acquired 2D CT DICOM data were input on a computer, and the reformatted 3-D images were created using a 3-D image software. Twenty three measurements were established in order to evaluate asymmetry; 15 ;omear measurements (6 for ramus length. 1 for condylar neck length, and 8 for mandibular body length) and 8 angular measurements (4 for gonial angle. 2 for frontal ramal inclination. and 2 for lateral ramal inclination) The right aid left difference of each measurement was calculated and analyzed. It is suggested that the right and left differences of the measurements obtained from the study could be used as references for the diagnosis of facial asymmetric patients.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.448-457
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• 2004

As computer Programs for cephalometric analysis were developed in diagnosis & treatment planning, digital imaging of film-based cephalograms came to be needed. When a digital camera is used, a problem encountered the image distortion produced according to the focal length, which causes errors in indentifying landmarks. In addition, changes in the image size and compression ratio will inevitably produce a low quality image, causing errors in identifying landmarks. Hence. we have found the focal length producing the least image distortion when digital imaging the film-based cephalograms and the minimal digital camera setting which helps to identify the correct landmarks using the COOLPIX4500 digital camera (Nikon, Japan). The results were as follows The image distortion was minimized at a focal length of 16.4mm (79.4mm when converted into a 35mm film camera) when digital imaging the film-based cephalograms. When wide imaging, with a focal length of under IS.4mm, barrel distortion was found and when tole imaging. with a focal length of over 15.4mm pincushion distortion was found. The minimal digital camera setting was $2272{\times}1704$ pixel at normal (1/8) compression from which we can identify the correct landmarks at the same level as tracing the film-based cephalograms manually. As a result. when digital imaging the film-based cephalograms, using a COOLPIX4500 digital camera (Nikon, Japan), the focal length should be 16.4mm the pixel image size over $2272{\times}1704$, and the compression ratio over normal (1/8).

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.165-180
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• 2007

Dental Implants have been proved to be successful prosthetic modality in edentulous patients for 10 years. However, there are few reports on the survival of implant according to location in molar regions. The purpose of this study was to evaluate the $4{\sim}5$ years' cumulative survival rate and the cause of failure of dental implants in different locations for maxillary and mandibular molars. Among the implants placed in molar regions in Gwangju Mir Dental Hospital from Jan. 2001 to Jun. 2002, 473 implants from 166 patients(age range; $26{\sim}75$) were followed and evaluated retrospectively for the causes of failure. We included 417 implants in 126 periodontally compromised patients, 56 implants in 40 periodontal healthy patients, and 205 maxillary and 268 mandibular molar implants. Implant survival rates by various subject factors, surgical factors, fixture factors, and prosthetic factors at each location were compared using Chi-square test and Kaplan-Meier cumulative survival analysis was done for follow-up(FU) periods. The overall failure rate at 5 years was 1O.2%(subject level) and 5.5%(implant level). The overall survival rates of implants during the FU periods were 94.5% with 91.3% in maxillary first molar, 91.1% in maxillary second molar, 99.2% in mandibular first molar and 94,8% in mandibular second molar regions. The survival rates differed significantly between both jaws and among different implant locations(p<0.05), whereas the survival rates of functionally loaded implants were similar in different locations. The survival rates were not different according to gender, age, previous periodontal status, surgery stage, bone graft type, or the prosthetic type. The overall survival rate was low in dental implant of too wide diameter(${\geq}5.75$ mm) and the survival rate was significantly lower for wider implant diameter(p

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.168-173
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• 2011

This study investigated characteristics of dose distribution at junction field of X-ray and electron beams according to the method for fabricating the insert block on the electron cone. Insert block were fabricated to the divergency cutout block and the straight cutout block. For the 6 MV X-ray and 10 MeV nominal energy of electron beam, we was adjacent to the light field of X-ray and electron beam at a surface of matrix chamber and measured to beam profile of abutted field in the 0, 1, 2, 3 cm measurement depth. As a result, characteristics of dose distribution at junction field, straight block was existent that over dose area exceed the give dose more than 5% and under dose area with a rapid change in dose distribution. However, divergency block had remarkably decreased the over dose area caused by the lateral scattering effects of decrease, and being existed uniformity dose distribution in the junction field. Therefore, divergency block were the benefits of radiation dose delivery, in order to applied the clinical, measurement of electron beams according to the fabrication method of the block should be considered carefully.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.169-180
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• 2014

Chemical weathering of forest soils can reduce atmospheric $CO_2$ concentration over geologic time scales, providing many essential elements for life. Although many studies have been conducted on the effects of elevated atmospheric $CO_2$ on forest carbon storage using open top chambers and FACE (Free air $CO_2$ enrichment) facilities since the 1990s, studies on chemical weathering of forest soils under elevated $CO_2$ are relatively rare. Here I review on how elevated atmospheric $CO_2$ can affect the chemical weathering of forest soils and suggest directions on future research. Despite the recent advances in chemical weathering of forest soils under elevated atmospheric $CO_2$, it is still not clear how the large volume of forest soils would react under the condition. Future studies on weathering of forest soils covering large areas from the tropics to the polar regions with carefully monitored pre-treatment data would provide key information on how soils, the Earth's life sustaining engine, change under climate change.

• Journal of the Korea Convergence Society
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• v.8 no.6
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• pp.55-64
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• 2017

The research study focuses to analyze the result of the military personnel medical examination and identify the medical conditions of military individuals. The results of this study are as follows. First of all, for the general features of research subjects, there are 60 people who are 39-year-old or less and 60 people in the age of 40-year-old or over of the total 120 research subjects. Secondly, as a result of canonical correlation analysis in between their ages/body mass index(BMI) and the outcomes of medical examination, it derived 3 canonical functions. 2 of the functions out of the 3 demonstrated statistical significance. The research has conjured meaningful results which include that the holistic diagnosis and treatment system for the military officers needs additional enhancement. Also the medical examination is in desperate need of expansion in test items and the associated budget planning should be evaluated in government organizations related to welfare policy.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.531-536
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• 2004

In fracture treatment with external fixators, the inter-fragmentary movements at the fracture site affect the fracture healing process, and these movements are highly related to the stiffness of external fixation systems. Therefore, in order to provide the optimal fracture healing at the fracture site, it is essential to understand the relationship between the stiffness and the system configurations in external fixation system. In this study we investigated the influences of system configuration parameters on the stiffness in the finite element analysis of an external fixation system of a long bone. The system alignment, the geometric and the material non-linearity of the pin, the joint stiffness and the callus formation were considered in the finite element model. In the first, the system stiffness of the developed finite element model was compared with the experiment data for model validation. The consideration of the joint stiffness and nonlinearity of the model improved the system stiffness results. The joint stiffness, the non-alignment of the system decreased the system stiffness while the callus formation increased the system stiffness. The present results provided the biomechanical basis of rational guidelines for design improvements of external fixators and pre-op. planning to maximize the system stiffness in fracture surgery.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.317-321
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• 2012

This study was carried out to investigate the effect of EC levels in nutrient solution on the growth of rose in coir substrate during the juvenile. Nutrient concentration were EC 0.6, 1.0, 1.4, and $1.8dS{\cdot}m^{-1}$. In spite of high concentration of nutrient solution was supplied, EC and inorganic ions content in the extract of substrate was no difference by 22 days after planting. After that, they was rapidly increased with higher concentration of nutrient solution. Number of shoot was highest in EC $1.8dS{\cdot}m^{-1}$ at 2nd growth cycle, 90 days after planting, after that was showed a tendency to increase with increasing nutrient concentration, but was no significant difference among treatment except EC $0.6dS{\cdot}m^{-1}$. Judging by results of growth of rose and contents of inorganic ion in extracts of media, our experiment suggests that the suitable nutrient concentration is EC $1.8dS{\cdot}m^{-1}$ until 90 days and then EC $1.4dS{\cdot}m^{-1}$ until 165 days after planting that is more higher than conventional nutrient concentration for absorption by coir.