• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.234-238
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• 2016

Purpose: Increasing use of computer aided design-computer aided manufacturing (CAD-CAM) system and number of design software made design of restoration easy and quick. Outcome of restoration has been dependent on dental technician's wax up proficiency, dentists can design restoration for themselves now. This study aims to investigate the outcome of restoration designs, according to handling skill of CAD-CAM design tool. Materials and methods: A patient's mandibular right 1st molar was prepared. After taking impression, stone model was made, scanned the stone model with 3 shape intra-oral scanner, stereolithography (STL) file was extracted. With 3shape dental designer, one dental technician with more than 5 years work experience (designer 0) and three dental technicians with less than 2years work experience (designer 1, 2, 3-group DT) and 4 1st year residents (designer 4, 5, 6, 7-group RT) designed gold crown on the same STL file. Designed crown's MD (mesio-distal) and BL (bucco-lingual) diameter, height of crown, inter-cuspal distance, number of occlusal contact points were compared. Statistical analysis was carried out, test of normality within each group, using independent t-test. Number of contact points were compared, using Wilcoxon signed-rank test. Results: There was no significant difference between group DT and group RT. Number of contact points also resulted in no significant difference. Conclusion: The outcome of each designed crowns showed no statistical differences, in values which can be expressed as numbers. Subjective factors were different. With increasing proficiency in handling designing software, fabrication of restorations according to each designer's occlusal concept can be made easy.

• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.169-179
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• 2007

This study was to compare the microshear bond strength $({\mu}SBS)$ of light- and chemically cured composites to enamel coupled with four 2-step self-etch adhesives and also to evaluate the incompatibility between 2-step self-etch adhesives and chemically cured composite resin. Crown segments of extracted human molars were cut mesiodistally, and a 1 mm thickness of specimen was made. They were assigned to four groups by adhesives used: SE group (Clearfil SE Bond) AdheSE group (AdheSE), Tyrian group (Tyrian SPE/One-Step Plus), and Contax group (Contax) Each adhesive was applied to a cut enamel surface as per the manufacturer's instruction. Light-cured (Filtek Z250) or chemically cured composite (Luxacore Smartmix Dual) was bonded to the enamel of each specimen using a Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to ${\mu}SBS$ testing with a crosshead speed of 1 mm/minute. The mean ${\mu}SBS$ (n=20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at 95% level. Also the interface of enamel and composite was evaluated under FE-SEM. The results of this study were as follows ; 1. The ${\mu}SBS$ of the SE Bond group to the enamel was significantly higher than that of the AdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin (p < 0.05). 2. There was not a significant difference among the hdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin. 3. The ${\mu}SBS$ of the light-cured composite resin was significantly higher than that of the chemically cured composite resin when same adhesive was applied to the enamel (p < 0.05). 4. The interface of enamel and all 2-step self-etch adhesives showed close adaptation, and so the incompatibility of the chemically cured composite resin did not show.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.323-329
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• 2006

The aim of this study was to evaluate the retrievability of Resilon as a root canal filling material Twenty-seven human single-rooted extracted teeth were instrumented utilizing a crown down technique with Gates-Glidden burs and ProFile system. In group1 (n = 12) canals were obturated with gutta percha and AH-26 plus sealer using a continuous wave technique and backfilled. In group 2 (n = 15) Resilon was used as a filling material. Then teeth were sealed and kept in $37^{\circ}C$ and 100% humidity for 7 days. For retreatment, the samples were re-accessed and filling material was removed using Gates-Glidden burs and ProFiles. Teeth were sectioned longitudinally to compare the general cleanliness and amount of debris $({\times}\;75)$ using SEM. Chi-square test was used $({\alpha}\;=\;0.05)$ to analyze the data. The total time required for removal of filling materials was expressed as mean ${\pm}SD$ (min) and analyzed by the Student t-test $({\alpha}\;=\;0.05)$, Required time for retreatment was $3.25\;{\pm}\;0.32$ minutes for gutta percha/ AH 26 plus sealer and $3.05\;{\pm}\;0.34$ minutes for Resilon. There was no statistically significant difference between the two experimental groups. There was no significant difference between the groups in the cleanliness of the root canal wall. This study showed that Resilon was effectively removed by Gates-Glidden burs and ProFiles.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.2
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• pp.82-89
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• 2013

Purpose: The present study is aimed to evaluate the combined effect of recombinant human bone morphogenetic protein 2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF) coated onto anodized implants on osseointeration. Materials and methods: Six New Zealand white rabbit were used in this study. Each animal received 4 implants that were either coated with rhBMP-2 and rhVEGF (Study group) or anodized implant (Control group) in both tibia. This was performed using a randomized split-mouth design. A total 24 implants were used. The implant stability quotient (ISQ) value using resonance frequency analyser and removal torque (RTQ) measurement were investigated at 2 and 8 weeks. The t-test was used for statistical analysis (${\alpha}$=.05). Results: Control and study group showed good osseointegration at 8 weeks. The ISQ and RTQ values of study group were significant compared with the control group at 8 weeks (P<.05). However, No statistical significance was observed at 2 weeks (P>.05). Conclusion: It was concluded that rhBMP-2 with rhVEGF coated onto anodized implants can induce better osseointegration at late healing period.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.300-306
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• 2013

Purpose: This study was to evaluate the accuracy of how to use the Mechanical Torque-Limiting Devices. Materials and methods: Three different implant manufacturers (Dentium, Osstem, Shinhung) were prepared for each two implant torque controllers. Divided into two groups depending on the method used for removal torque was measured. Repeated measures of ANOVA test (${\alpha}=.05$) was used as statistics to evaluate the effect of repeated loading number on the removal torque. Independent t-test was used to evaluate the difference in removal torque of two groups. Results: The removal torque significantly decreased as the number of loading repetition increased (P<.05). There was significant difference between two groups. Conclusion: Loosen the handle part of the implant torque controllers spring resilience to recover one group compared to the group that did not, showed a little more closed to the reference value.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5261-5270
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• 2012

The present study is designed to compare the mortality and potential years of life lost of colorectal cancer between OECD countries and Korea before (1990-1999) and after (2000-2009) to provide data of more accurate strategy of public health policy and education about cancer treatment and prevention through examining differences of changes among the OECD countries. We statistically compared mortality and potential years of life lost from 32 OECD countries including Korea, except 2 nations with inadequate data, between before (1990-1999) and after the year 2000 (2000-2009) using 'OECD Health Data 2012' using the method of paired t-test. Male mortality of colorectal cancer was increased in 8 OECD countries including Korea and the female mortality was only increased in Chile and Korea. In particular, the increased rate of mortality was significantly high in Korean male and female. Moreover, increased rate of potential years of life lost for colorectal cancer was also significantly high in Korea: the rate in Korean male was increased over three times than in Mexico (2nd rank of the increase) and the rate of female was only increased in Korea compared with other countries, interestingly. Therefore, the present study suggested that most OECD countries well controlled the incidence and treatment of colorectal cancer after 2000 but Korea did not. From these, to control future problems, the further studies for the reason of the increase of potential years of life lost in female will be needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5299-5304
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• 2012

MRI signals are significantly reduced by the magnetic field inhomogenity result from human body itself being consisted of various materials like air, fat, muscle, bone and blood vessels. In this study we used silicon which is tissue equivalent to compensate wound body shapes. Objects were eight adults who do not have any special symptoms. Feet were scanned because of their complicated structures and consequently signal reduction occurs a lot. Thirty images were acquired from the middle of arcus pedis longitudinalis including five distal phalanges parallel to the line connecting metatarsal bone and phalanges. SNR data from bones and soft tissues were compared before and after sticking silion between toes and paired t test was performed. It was came out that SNR data from bone and soft tissue were both significantly higher after applying silicon on both T1 and T2 weighted images and it was statistically meaningful having positive corelation. As a result, this study dramatically increases SNR without affecting object by increasing the object volume inside the surface coil.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.244-250
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• 2020

The aim of the study is to investigate the effect of the benefit of soft waxing, hard waxing, and sugaring waxing on intention to reuse in Korean adults, and to provide useful information to people who are new to waxing. As a research method, from May 1, 2019 to August 30 (17 weeks), we surveyed 422 subjects between 10 and 40 years old who lived in Busan and Yeongnam area and experienced waxing. In statistical analysis, Cronbach's alpha was calculated for reliability test, and Chi-squared test, independent t-test, correlation analysis and linear regression analysis were used. Multiple responses were analyzed using multiple response test. In the result of the effect of waxing benefit on intention to reuse, there was a significant positive correlation of waxing seeking score by body part, total waxing benefit score(r=0.389, p<0.001), and total score of intention to reuse (r=0.214, p>0.001) with intention to reuse. There was also a significant positive correlation between waxing benefit by body part and intention to reuse, except arms and legs. In the result of the effect of waxing benefit on intention to reuse, face waxing (β=0.106, p<0.001), Brazilian waxing (β=0.221, p<0.001) and total waxing benefit score (β=0.321, p<0.001) had a significant effect on intention to reuse. In the present study, awareness of sugaring waxing was low but favor and intention to reuse were strong, and the subjects sought sugaring waxing for sensitive body parts. Thus, would provide useful information for consumers new to waxing, and also basic information for studies on waxing.

• The Journal of Korean Academy of Sensory Integration
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• v.18 no.1
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• pp.13-22
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• 2020

Objective : This study was conducted to confirm general differences in eating attitudes according to the sensory processing characteristics of women. Methods : The Adolescent/Adult Sensory Profile (AASP) and the Eating Attitude Test (EAT-26) were used to survey 241 women. Their eating attitudes according to the sensory processing characteristics was analyzed using an independent t-test and one-way ANOVA, and the post-analysis was performed using the Scheffe test. Results : Among the sensory processing characteristics, except for eating control due to low registration, binge-eating and foodlessness due to sensory avoidance, all eating attitudes were significantly different according to sensory processing characteristics (p<.05). The anorexic behaviour, binge-eating and foodlessness was shown to be negative in cases of those who had much lower registration than most people. All eating attitudes, such as anorexia, binge-eating and foodlessness, and eating control, were shown to be negative in cases of women whose sensation seeking was equal to or much greater than the general population. The binge-eating and foodlessness were shown to be negative in cases of high sensory sensitivity. The anorexic behaviour was shown to be negative in cases of elevated sensory avoidance. Conclusion : Eating attitudes differed depending on the sensory processing characteristics. As such, sensory integration mediation can be proposed as a method of controlling the eating attitudes of women in general.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.244-250
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• 2017

The most important aspect determining the completeness of aprosthesis is itsmarginal and internal fit. Alloysare processed using a softening/hardening heat treatment methodin order to improve their mechanical, physical properties and polishing properties. To examinehow the heat treatment method affects the marginal and internal fit of the Ni-Cr alloy core,thirty dental stone models of the abutment of the mandibular left molar were manufactured.The Ni-Cr alloy coreswere manufactured by the dipping method for the experiment and dividedinto three groups; A for no heat treatment, B for softening heat treatment and C for hardening heat treatment. The marginal and internal fitsof all of the groups were measured by the silicone replica technique. A statistical analysis was performed using one-way ANOVA(${\alpha}=0.05$) in order to examine whether there is a significant difference in the average values of the marginal and internal fits among the three groups and it was found that themarginal fits (1, 6) were significantly different (p<0.05), but the internal fits (2, 3, 4, 5) were not significantly different (p>0.05). These results show that Ni-Cr alloys should not be processed bythe heat treatmentmethod.However, they need to be confirmed in further clinical application studies.