• The korean journal of orthodontics
• /
• v.27 no.4 s.63
• /
• pp.549-557
• /
• 1997

This study was designed to investigate the attrition pattern in Angle Class III malocclusion with facial asymmetry. The sample consisted of three groups, the 20 subjects of normal occlusion group(Group I), the 12 subjects of class III malocclusion without facial asymmetry group(Group II) and 17 subjects of Class III malocclusion with facial asymmetry group(Group III). Attrition areas from canine to second molar on both sides in upper and lower arch, totally twenty, was marked by pencil and mesured by computer system(INTERGRAPH CO. USA) 2 times and the average value was used for date processing. Attrition areas from canine to second molar on both sides in upper and lower arch, totally twenty, was marked by pencil and mesured by computer system(INTERGRAPH CO. USA) 2 times and the average value was used for date Processing. All attrition areas were measured 2 times and the average value was used for data processing The data were statistically analyzed by SAS program. The results of this study were as follows. 1. Total attrition area in Group I was larger than in Group II and III. 2. There was no significant difference in attrition area between right and left side in each group, but attrition area in Group III was larger than in Group I and II. 3. In Group I, Maxillary attrition area was larger than mandibular attrition area, but in Group ll and III, there was no significant difference in attrition area between maxilla and mandible. 4. In Group III, the attrition area of deviated side was target than undeviated side 5. There was no significant difference in attrition area between chewing side and non-chewing side in each group. 6. The total attrition area was unaffected by gender.

• The Journal of Korean Academy of Prosthodontics
• /
• v.60 no.2
• /
• pp.135-142
• /
• 2022

Purpose. This study aims to evaluate the combined effect of reduced thickness in different regions on the fracture resistance of monolithic zirconia crowns. Materials and methods. Seven nickel-chromium dies were generated from a 3D model of mandibular first molar using the digital scanner with the following geometries: 1.5 mm occlusal reduction, 1.0 mm deep chamfer. Based on the abutment model, Zirconia blocks (Luxen Zirconia) were selected to fabricate Sixty-three zirconia crowns with occlusal thicknesses of 0.3 mm, 0.5 mm, and 1.5 mm, and different axial thicknesses of 0.3 mm, 0.5 mm, and 1.0 mm. All crowns were cemented by resin cement. Next, the crowns were subjected to load-to-fracture test until fracture using an electronic universal testing machine. In addition, fracture patterns were observed with a scanning electron microscope (SEM). Two-way ANOVA and the Tuckey HSD test for post hoc analysis were used for statistical analysis (P < .05). Results. The mean values of fracture resistancerecorded was higher than the average biting force in the posterior region. The two-way ANOVA showed that the occlusal and axial thickness affected the fracture resistance significantly (P < .05). However, the effect of axial thickness on fracture resistance did not show a statistical difference when thicker than 0.5 mm. The observed failure modes were partial or complete fracture depending on the severity of crack propagation. Conclusion. Within the limitations of the present study, the CAD-CAM monolithic zirconia crown with extremely reduced thickness showed adequate fracture resistance to withstand occlusal load in molar regions. In addition, both occlusal and axial thickness affected the fracture resistance of the zirconia crown and showed different results as combined.

• The korean journal of orthodontics
• /
• v.30 no.2 s.79
• /
• pp.261-272
• /
• 2000

Severe skeletal anteroposterior and vertical discrepancy is difficult to obtain satisfactory result by only orthodontic treatment, and much anteroposterior movement and treatment stability require orthodontic treatment with orthognathic surgery. The treatment goal of mandibular prognathic patients is to promote the function of stomatognathic system including mastication and phonetics, to improve the esthetics of facial profile and to maintain stability. Positional changes of hyoid bone, pharynx and tongue were seen with mandibular movement after orthognathic surgery. This study was performed to observe the changes of perimandibular tissues of orthodontic patients with skeletal mandibular prognathism who treated with orthodontic treatment, and the changes of hyoid bone, pharyx and tongue by relapse or recurrance after before and after orthognathic surgery and retention. The 22 patients who had mandibular prognathism were selected. They treated with orthodontic treatment with sagittal split ramus osteotomy as orthognathic surgery. And lateral cephalometric radiographs were taken 3 times : pre-surgery (T1), immediate post-surgery (T2) and 2 years alter retention (T3). The results were as follows : 1. The hyoid bone returned back after clockwise rotation to maxilla and occlusal plane during retention (P<0.01). 2. The hyoid bone moved posterior-inferiorly by mandibular surgery and returned back anterior-superior after retention. (P<0.01) 3. The changes of pharyngeal depth showed a little decrease at upper area in post- surgery, but it was not a significant difference generally through before, after and retention. 4. In relating to tongue base, the angle of tongue base was decreased and the dorsal area of tongue base moved to inferior-posterior direction and to superior direction again after retention (P<0.01). 5. Related to the thickness of upper and lower lip, the thickness of upper lip decreased after surgery, and the soft tissues below lower lip increased after surgery and decreased after retention.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.46 no.3
• /
• pp.14-26
• /
• 2018

The Biotope Area Ratio (BAR) is a quantitative pre-planning index for sustainable development and an integrated indicator for the balanced development of buildings and outdoor spaces. However, it has been pointed out that there are problems in operations management: errors in area calculation, insufficiency in the underground soil condition and depth, reduction in biotope area after construction, and functional failure as a pre-planning index. To address these problems, this study proposes implementing LIM. Since the weights of the BAR are mainly decided by the underground soil condition and depth with land cover types, the study focused on the terrain and pavements. The model should conform to BIM guidelines and standards provided by government agencies and professional organizations. Thus, the scope and Level Of Detail (LOD) of the model were defined, and the method to build a model with BIM software was developed. An apartment complex on sloping ground was selected as a case study, a 3D terrain modeled, paving libraries created with property information on the BAR, and a LIM model completed for the site. Then the BAR was calculated and construction documents were created with the BAR table and pavement details. As results of the study, it was found that the application of the criteria on the BAR and calculation became accurate, and the efficiency of design tasks was improved by LIM. It also enabled the performance of evidence-based design on the terrain and underground structures. To adopt LIM, it is necessary to create and distribute LIM library manuals or templates, and build library content that comply with KBIMS standards. The government policy must also have practitioners submit BIM models in the certification system. Since it is expected that the criteria on planting types in the BAR will be expanded, further research is needed to build and utilize the information model for planting materials.

• The Journal of the Korea Contents Association
• /
• v.14 no.3
• /
• pp.250-258
• /
• 2014

The purpose of this study was to promote effective health management of orthodontics patients by determining the effect that the factors related to orthodontics would have on the Oral Health Impact Profile (OHIP), and the subjects of this study was the local residents of Gangwon-do Province. The mean score of OHIP for the subjects was 2.97, while the mean score of physical factor was 3.01. The mean score of psychological factor was found to be 2.93. Thus, the orthodontics was found to have more influence on psychological factor. The item that had the greatest influence among the 10 items of Oral Health Impact Profile was found to be the question, "Have you ever felt shy due to your dental shape?" which had the mean score of 2.66. The characteristics that had significant effect on OHIP among general characteristics were found to be the age, religion, occupation, income, smoking or non-smoking status(p<0.05). In terms of the age, the age of 20 or less had the greatest effect with the mean score of 2.53. In relation to the occupation, the production/sales occupation had an influence with the mean score of 2.56 (p<0.05). Those with income exceeding KRW 4 million were found to have the mean score of 2.83 and 2.78. It turned out that the smokers had greater effect compared to the non-smokers in relation to the smoking/non-smoking status as the income was higher (p<0.05). The characteristics of orthodontics were manifested as the health perception in relation to Oral Health Impact Profile (OHIP) (p<0.05). Regarding the reason why they underwent the orthodontics, the 'uncomfortable feeling in chewing' was found to have the mean score of 2.69 and 2.67 (p<0.05). Regarding the orthodontics period, 1 to 2 years were found to have the mean score of 2.80 and 2.74, thus having an influence (p<0.05). In relation to the regret/non-regret over orthodontics, those who indicated that they regretted were found to have the mean score of 2.65 and 2.60 (p<0.05). Analysis of the relationship between Characteristics of orthodontic treatment and OHIP, orthodontic treatment reasons, oral health awareness, whether orthodontic treatment regret showed a statistically significant correlation. it is considered necessary to make constant efforts to help orthodontics patients, both physically and psychologically, in the course of treatment and improve their quality of lives.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.spc1
• /
• pp.19-23
• /
• 2005

This study was carried out to compare the rice quality between domestic brand rice and imported Chinese rice. In the appearance of grain, head rice rates were $96.1\%$ in domestic brand rice (Ilpumbyeo), $94.1\%$ in Jingguan (Chinese brand rice) and $86.5\%$ in Xiaozhandao(Chinese brand rice). In case of Chinese parboiled rice, the head rice rate was $0\%$ because the cracked and broken rice occupied about $95.5\%$. The low protein contents in Ilpumbyeo and Xiaozhandao as 6.5 and $6.7\%$ show relatively high palatability as 81.9 and 71.4. However, high protein contents in Jingguan and Chinese parboiled rice as 7.5, $7.4\%$ show low palatability as 64.3 and 55.6. In viscosity characteristics, peak viscosity, break down and final viscosity were higher in Ilpumbyeo and Xiaozhandao, midium in Jingguan and lowest in Chinese parboiled rice. And the set back value, which was negatively related with amylose content, was lowest in Ilpumbyeo and highest in Chinese parboiled, suggesting slow deterioration in Ilpumbyeo and rapid deterioration in Chinese parboiled rice. Overall physical components of cooked rice measured by Texture Analyser were higher in Ilpumbyeo than those in Chinese parboiled rice.

• The korean journal of orthodontics
• /
• v.36 no.3 s.116
• /
• pp.188-197
• /
• 2006

Fiber reinforced composite (FRC) is usually used as a connector joining a few teeth into one unit in orthodontics. However, fracture often occurs during the two to three years of the orthodontic treatment period due to repeated occlusal loading or water sorption in the oral environment. We simulated the repair by overlapping and attaching portions of two FRC strips in the middle and performed a three-point bending test to investigate the changes of the repair strength among the different FRC groups. The specimens were grouped according to the overlapping lengths of the two FRC strips, which were 1, 2, 3 and 4 mm (group E1, E2, E3 and E4, respectively) and the control group consisted of unrepaired, intact FRC strips. Each group consisted of 6 specimens and were cured with a light emitting diode curing unit. Group E4 showed the highest maximum loads of 2.67 N, then the control group (2.39 N), group E3 (2.35 N), E2 (2.10 N), and E1 (1.75 N) in decreasing order. Group E4 also showed the highest stiffness, which was 2.32 N/mm, however, the stiffness of group E3 (2.06N/mm) was higher than that of the control group (1.88 N/mm). According to the visual examination, the specimens tended to be bent rather than being fractured into two pieces with an increased length of overlapping portions. The above results suggest that a minimum overlapping length of 3 mm was necessary to obtain an adequate repair of a 10 mm length of FRC connector. In addition, the critical section adjacent to the joint area, where the thickness decreased abruptly, should be reinforced with flowable resin to minimize the bending tendency.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.2
• /
• pp.179-195
• /
• 2010

In the internal connection system, the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. The purpose of this study was to assess the loading distributing characteristics of three different abutments for GS II$^{(R)}$ implant fixture(Osstem, Korea) under vertical and inclined loading using finite element analysis. Three finite element models were designed according to three abutments; 2-piece Transfer$^{TM}$ abutment made of pure titanium(GST), 2-piece GoldCast$^{TM}$ abutment made of gold alloy(GSG), 3-piece Convertible$^{TM}$ abutment with external connection(GSC). This study simulated loads of 100N in a vertical direction on the central pit(load 1), on the buccal cusp tip(load 2) and $30^{\circ}$ inward inclined direction on the central pit(load 3), and on the buccal cusp tip(load 4). The following results were obtained. 1. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture and lower stress was taken at the cancellous bone. 2. When off-axis loading was applied, high stress concentration observed in cervical area. 3. GSG showed even stress distribution in crown, abutment and fixture. GST showed high stress concentration in fixture and abutment screw. GSC showed high stress concentration in fixture and abutment. 4. Maximum von Mises stress in the surrounding bone had no difference among three abutment type. In GS II$^{(R)}$ conical implant system, different stress distribution pattern was showed according to the abutment type and the stress-induced pattern at the supporting bone according to the abutment type had no difference among them.

• Journal of the Korea Computer Graphics Society
• /
• v.6 no.4
• /
• pp.1-7
• /
• 2000

Traditionally, three dimension model s have been used for building virtual worlds, and a data structure called the "scene graph" is often employed to organize these 3D objects in the virtual space. On the other hand, image-based rendering has recently been suggested as a probable alternative VR platform for its photo-realism, however, due to limited interactivity. it has only been used for simple navigation systems. To combine the merits of these two approaches to object/scene representations, this paper proposes for a scene graph structure in which both 3D models and various image-based scenes/objects can be defined. traversed, and rendered together. In fact, as suggested by Shade et al. [1]. these different representations can be used as different LOD's for a given object. For in stance, an object might be rendered using a 3D model at close range, a billboard at an intermediate range. and as part of an environment map at far range. The ultimate objective of this mixed platform is to breath more interactivity into the image based rendered VE's by employing 3D models as well. There are several technical challenges in devising such a platform : designing scene graph nodes for various types of image based techniques, establishing criteria for LOD/representation selection. handling their transition s. implementing appropriate interaction schemes. and correctly rendering the overall scene. Currently, we have extended the scene graph structure of the Sense8's WorldToolKit. to accommodate new node types for environment maps. billboards, moving textures and sprites, "Tour-into-the-Picture" structure, and view interpolated objects. As for choosing the right LOD level, the usual viewing distance and image space criteria are used, however, the switching between the image and 3D model occurs at a distance from the user where the user starts to perceive the object's internal depth. Also. during interaction, regardless of the viewing distance. a 3D representation would be used, if it exists. Finally. we carried out experiments to verify the theoretical derivation of the switching rule and obtained positive results.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.36 no.3
• /
• pp.137-148
• /
• 2018

Li Yu's Xian Qing Ou Ji was written during the late Ming and early Qing Dynasty when material culture flourished due to the development of the commercial economy. Xian Qing Ou Ji is considered a retrospective work that reflects the rich material society at that time. This study focuses on his gardening theories through the interpretation and analysis of these two texts of 'Jushibu(居室部)' and 'Zhongzhibu(種植部)' in Xian Qing Ou Ji. The results are summarized as follows. First, he explained the method of garden configuration and orientation according to the topography utilizing the theory of 'suiting one's measures to local conditions(因地制宜)'. He emphasized the detailed understanding of topography as the starting point for all the gardening theories. It stated that he tried to adjust the height of the terrain artificially to create an ideal form of 'anterior high and posterior low(前低後高)'. The successful arrangement of houses, pavilions, rockery and waterways et al. was able to be achieved because of his accurate understanding of topography. Second, 'borrowing scenery(取景在借)' means 'borrowing the outside scenery to the inside'. He applied this theory by 'viewing in motion(動觀)' and 'viewing in repose(靜觀)'. 'Viewing in motion' is seen as a positive methodology for landscape enjoyment. For example, the view through a window changes with movements of the boat, and it can portray thousands of landscape paintings which can be seen through the windows. In the case of 'viewing in repose', the window is regarded as a means of attracting outside garden views to the inside. Third, he emphasized 'the firmness of objects(制體宜堅)', where the design of windows and railings must be considered ahead of others. Fourth, he interpreted the contents of 'the pursuit of novelty(創異標新)'. This generalizes the characteristics of his gardening theory. The contents included 'hall wall(廳壁)', 'variable sun visor(活?)', 'hanging boards and couplets(聯?)' and 'method of supporting vines with bamboo screen(竹屛扶植法)'.