• Journal of the Korean Academy of Esthetic Dentistry
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• v.29 no.2
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• pp.75-83
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• 2020

For the successful prosthetics treatment, the collaboration starting from the initial stage between dental clinic and laboratory is important. However, the collaboration can't persist all the processes, giving the ideal shape to prosthetics is one of the responsible part of dental laboratory. I'm going to explain how to access dental technician to case in restricted circumstance.

• The Journal of the Korean dental association
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• v.11 no.12
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• pp.811-820
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• 1973

• The Journal of the Korean dental association
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• v.10 no.11
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• pp.773-775
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• 1972

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.36-42
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• 2000

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.597-606
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• 1999

This study was performed to evaluate the effect of aging and thermal cycling on the biaxial flexure strength of low commercially available veneering resin composites for crown(Dentacolor : DC, Artglass : AG, Esternia : ET and Targis : TG). Disc specimens were fabricated in a teflon mold giving 12mm in diameter and 1mm in thickness. All samples were divided into 4 groups. Group 1 was dried in a dessicator at $25^{\circ}C$ for 30 days. Group 2 was immersed in distilled water at $37^{\circ}C$ for 30 days. Group 3 was immersed in distilled water at $65^{\circ}C$ for 30 days. Group 4 was subjected to 10,000 thermal cycles between $5^{\circ}C\;and\;55^{\circ}C$, and the immersion time in each bath was 15 seconds per cycle. Biaxial flexure test was conducted using the ball-on-three-ball method at the cross head speed of 0.5mm/min and fracture surfaces were observed with scanning electoron microscope. The results obtained were summarized as follows; 1. Weibull modulus values, except for the AG group, decreased after thermal cycling treatment. 2. Biaxial flexure strength values of aging group at $37^{\circ}C$ were the lowest in all sample groups. Except for the DC group, strength values were significantly decreased for the drying group. 3. After thermal cycling test, the highest value of biaxial flexure strength of 188.8 MPa was observed in the ET group and the lowest value of 73.2 MPa was observed in the DC group. The strength values showed the significant differences in each group (p<0.05). 4. Observation of surfaces after thermal cycling test revealed the ditching in the part of surrounding large fillers.

• The Journal of Advanced Prosthodontics
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• v.4 no.3
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• pp.146-152
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• 2012

PURPOSE. The cortical bone thickness on the anterior region is important for achieving implant stability. The purpose of this study was to examine the thickness of the cortical and cancellous bones on the anterior region of the maxilla and mandible. MATERIALS AND METHODS. Twenty-five cadaver heads were used (16 male and 9 female; mean death age, 56.7 years). After the long axis of alveolar process was set up, it was measured in 5 levels starting from 2 mm below the cementoenamel junction (L1) at intervals of 3 mm. All data was analysed statistically by one-way ANOVA at the .05 significance level. RESULTS. The cortical bone thickness according to measurement levels in both the labial and lingual sides increased from L1 to L5, and the lingual side below L3 was significantly thicker than the labial side on the maxilla and mandible. In particular, the labial cortical bone thickness in the maxilla was the thinnest compared to the other regions. The cancellous bone thickness according to measurement levels increased from L1 to L5 on the maxilla, and on the mandible it was the thinnest at the middle level of the root. CONCLUSION. For implant placement on the anterior region, a careful evaluation and full knowledge on the thickness of the cortical and cancellous bone are necessary, therefore, these results may provide an anatomic guideline to clinicians.

• Journal of Technologic Dentistry
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• v.34 no.3
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• pp.291-302
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• 2012

Purpose: It is to survey old men's utilization status of dental clinic and temporary-binding dentures and then to provide basic data to make a program for manufacturing old men's dentures and their teeth health education. Methods: Random selection was made on old men living in Daejeon and Chungnam, and a survey was conducted from April 15 to May 20, 2011. 500 questionnaires were distributed and 420 questionnaires were collected. Using spss 18.0 program, final analysis was made on 363 questionnaires except for 57 questionnaires which had missing value or showed some doubts about the unreliability. Results: 1. With respect to number of natural teeth as per the age, the upper/lower jaws had meaningful differences (P<.001), which means that the older the person is, the smaller number of natural teeth is. In the meantime, there was no meaningful difference according to sex. 2. With respect to kind of prosthetics installed in a mouth as per the age, there was meaningful difference in the upper jaws (P<.05) but there was no meaningful difference in the lower jaws. It was found out that the older the persons are, the more they use removable dentures while the younger the persons are, the more they use fixed partial dentures. 3. With respect to mouth health condition recognized by oneself, it showed bad (44.4%) and good (10.3%),which means recognition as bad is greater, and the age when prosthetics were first used is dispersed variously from below 40 to over 70. 4. Dental care institutions which they mainly used are hospital and clinics (91.5%), and 66.4% of them visited dental clinics lately. Preferential treatment if they go to dentists is as follows in the order of prosthetics (33.9%), gum treatment (24.2%) and pain treatment (14.9%). 5. 68.4% of them revisited dentists after installation of dentures and the reason for revisit is as follows in the order of poorly fitted dentures (35.1%), painful gum 25.9%, regular check-up 25.4% and difficult chewing 9.6%. Conclusion: As our country enters into an aging society, mouth health problem of old men has come to a serious issue, and therefore, a survey was conducted on some old men with respect to their utilization status of dental clinic and removable dentures in order to provide basic data for improvement of quality of their life, maintenance and enhancement of their mouth health. The study result shows that the older they are, the higher the loss rate of teeth as well as needs for prosthetics are, and thus it is thought the study will help to develop mouth health education program which may improve quality of old men's life by recovery of mouth functions declined due to loss of teeth and by regular check-up, education for mouth health control and following-up control of dentures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.243-244
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• 2009

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.4
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• pp.383-396
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• 2000

Before the advent of early plastic or maxillofacial reconstructive surgery, facial features could only be replaced and mimicked by prosthetic, artificial means. Facial deformity or dysfunction, whether congenital or acquired by trauma or mutilating disease, has long been an area of constant research, development and innovation in many cultures of the world. One of the greatest contributors to the need for maxillofacial prosthetics has been physical conflict and warfare. The use of maxillofacial prostheses is not merely the replacement of a missing or disfigured aspect of the face, but the rehabilitation of that individual back into the society from which they originate. Rehabilitation includes the restoration of the person's self worth and confidence, not just physically but psychologically. In sixteenth century, Ambroise Pare, French military surgeon, first have tried many maxillofacial prosthetics for injured war soldiers with papier-mache, silver, gold and copper. According to patient's demand who lost their maxillofacial figures, maxillofacial personnel have increased and prosthetic's skill have been advanced all of the world. Over the last decade, there has been a very rapid development in technical possibilities to provide patients with facial prostheses retained by skin penetrating implants. This article will present overall history of maxillofacial prostheses and some background information on the materials used from the old world. And to overcome still many limitation of prosthetic, new minds and new ideas for technique and materials should be developed.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.107-115
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• 2017

In this paper, four-bar linkage mechanism for the knee joint is developed which is used in prosthetics. But unlike the prosthetics, the feature of this mechanism is that the instantaneous center of rotation of the four-bar linkages can be moved behind the ground reaction force vector so that it can be passively supported without any external power. In addition, this mechanism is developed similar to the structure of the human knee joint for eliminating the sense of heterogeneity of the wearer. In order to design the mechanism with these two objectives, optimization design process is done using the PIAnO tool and detailed design is carried out through optimized variable values. The developed mechanism is attached to the robot which can assist the hip and ankle joints. In order to verify the operation of the developed knee mechanism, an insole type sensor was attached to the shoes to compare data values before and after wearing the robot. Result data showed that wearer wearing the exoskeleton robot with the knee mechanism was the same value regardless of whether the heavy tool is loaded or not.