• The Journal of the Korean dental association
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• v.55 no.5
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• pp.339-350
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• 2017

The aim of the study was to analyze the distribution of dental filling materials for carious permanent teeth of school children in a city. The study was designed as time-serial study, using the data of the dental survey for children aged 8-, 10- and 12-year children living in Gimhae city. The samples were selected by stratified clusters sampling. The number of surveyed samples in depth-analysis for types of dental filling materials were 567 in 2009 and 331 in 2013, respectively. They had dental restorations on one or more teeth. The changing pattern of used dental filling materials was analyzed between 2009 and 2013. Statistical analysis was conducted according to variables related to dental filling material type; DMFT and DMFS index, number of fissure sealed teeth and surface and surveyed year. Amalgam filling rate decreased from 27.9% in 2009 to 18.8% in 2013, while filling rate of tooth-colored materials increased from 56.1% in 2009 and 68.9% in 2013. Amalgam filling rate was a negative correlation with filling rate of tooth-colored materials or gold and number of fissure sealed teeth and a positive correlation with DMFT index. Filling rate of tooth-colored materials was a negative correlation with filling rate of amalgam or gold and DMFT index and a positive correlation with number of fissure sealed teeth. The light-curing composite resin should be included in the reimbursement range of National Health Insurance to solve an inequity of dental health care services.

• Journal of Korean society of Dental Hygiene
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• v.22 no.6
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• pp.541-550
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• 2022

Objectives: This study aimed to verify the degree of clinical practice transition shock, resilience, and academic burnout of dental hygiene students, and analyze factors affecting academic burnout. Methods: From September 1 to September 20, 2022, this study collected data from 201 dental hygiene students who experienced clinical practice, and subsequently conducted a t-test, one-way ANOVA, Pearson correlation analysis, and multiple regression analysis using the SPSS Statistics 22. Results: The transition shock and resilience showed a significantly negative correlation (r=-0.211), transition shock and academic burnout showed a significantly positive correlation (r=0.484), and resilience and academic burnout showed a significantly negative correlation (r=-0.568). Regarding factors affecting academic burnout, academic burnout increased when the transition shock was greater (β=0.263, p<0.001), major satisfaction after clinical practice was lower (β=0.180, p<0.05), and the average grades were lower (β=0.169, p<0.01). Academic burnout decreased when resilience was greater (β=-0.435, p<0.001). Conclusions: To prevent clinical practice transition shock and academic burnout, and to increase the resilience of dental hygiene students, it would be necessary to establish learning strategies, change the educational environment, and establish a systematic clinical practice management program.

• The Journal of the Korean dental association
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• v.55 no.2
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• pp.166-171
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• 2017

Periodontitis is the major concern of oral disease to human, and begins in the interdental area. The aim of this study is to discuss the clinical application method and the meaning of interdental brush. It is very difficult to change oral health behaviors, because patients believe that it is enough that the reason of tooth brushing is to remove food debris, not dental biofilm. Moreover, there are several barriers for using interdental brush. For the better oral health and maintenance of dental prosthesis, it is very important to motivate the use of the interdental brush well, and teach the desirable design of the interdental brush and the clinical meaning to patients.

• Journal of The Korean Dental Society of Anesthesiology
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• v.12 no.3
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• pp.173-176
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• 2012

Certain oral procedures require a sedated patient who is responsive to allow for the mouth opening and position change. Dexmedetomidine is a relatively selective alpha2-adrenoceptor agonist with sedative, analgesic, amnestic, and anesthetic-sparing effects. Large dose dexmedetomidine is suitable as a single agent for sedation and anxiolysis for plate removal in a patient with bilateral sagittal split osteotomy and Lefort 1 osteotomy with genioplasty.

• Journal of Technologic Dentistry
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• v.32 no.4
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• pp.307-315
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• 2010

Purpose: The purpose of this study was to investigate the change of microstructures and mechanical properties of pure titanium casting specimens as a function of mold temperatures. Methods: The pure titanium castings were fabricated using the centrifugal vacuum casting method with different mold temperatures of $200{\sim}500^{\circ}C$. The resulting castings were characterized by optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and vicker,s hardness tester. Results: In case of the mold temperatures over $400^{\circ}C$, the porosity, surface crack and large grain size were observed in resulting castings. Conclusion: In this work, The most suitable mold temperature in casting of pure titanium was $300^{\circ}C$.

• Journal of Technologic Dentistry
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• v.32 no.4
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• pp.297-305
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• 2010

Purpose: The purpose of this study was to observe the change of metal-mold reaction and surface roughness in titanium casting specimens for phosphate-silica alumina bonded investment with mold temperatures. Methods: The metal-phosphate silica alumina bonded mold interface reaction and surface roughness of titanium casting specimens according to mold temperatures were investigated. The Specimens were analysed by scanning electron microscopy and surface roughness tester. Results: The oxidation behavior indicated by the growth of oxide thickness. The titanium-oxide layer were consisted two layer of a porous external and a dense internal one. The reaction layer and surface roughness increased with increasing investment material temperature. Conclusion: In this work, The most suitable mold temperature in casting of pure titanium was $200^{\circ}C$.

• Journal of Technologic Dentistry
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• v.24 no.1
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• pp.65-71
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• 2002

This study was performed to observe the microhardness change of the surface and the bonding strength between the porcelain and alloy specimens in order to investigate the effects of appended indium, tin and copper on interfacial properties of Au-Pd-Ag alloys. The hardness of castings was measured with a micro-Vicker's hardness tester. The interfacial shear bonding strength between alloy specimen and fused porcelain was measured with a mechanical testing system(MTS 858.20). The microhardness of Au-Pd-Ag alloy was increased by adding indium and tin, but not increased by adding copper. The shear bonding strength of Au-Pd-Ag-Sn alloy and Au-Pd-Ag-Cu alloy showed 87MPa, 57MPa. The higher concentration of adding elements showed the higher shear bonding strength.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.29-32
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• 2008

Dental high-speed air turbine handpieces have been used as a dental cutting tool in clinical dentistry for over 50 years, yet little study has been reported on their flow and performance analysis. Therefore it is necessary to investigate turbine for the performance improvements of an air turbine handpiece. This paper presents pressure on turbine rotor and flow analysis in air turbine handpiece using CFD (computational fluid dynamics). Characteristics on each flow and pressure for four various reflection angles of turbine rotor are presented, and then performance change is analyzed about air turbine handpieces by CFD results.

• Journal of Korean society of Dental Hygiene
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• v.8 no.4
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• pp.11-18
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• 2008

The purposes of this study were to examine the effect of 35% Carbamide Peroxide(CP) bleaching agent on the changes in physical and chemical characteristics of tooth. The effect of bleaching agent on enamel was analyzed using Hardness test, SEM and EDS. The microhardness between bleached groups after bleaching showed statistically significant difference according to the paired t-test. The bleached enamel surface showed apparent morphological changes compared to the enamel, which was stored in distilled water only. The difference of the total mineral contents for the distilled water and Carbamide Peroxide did not show statistical significance. These results demonstrated that bleaching using 35% Carbamide Peroxide were adversely affects application time of experimental group and may the safety of using these agents for a short time in dentist-monitored bleaching.

• Journal of dental hygiene science
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• v.15 no.6
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• pp.696-702
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• 2015

The purpose of this study was to evaluate the effect of oral health education with Q-scan for preschool children. The 59 children were divided into two groups, one with Q-scan and the other with dentiform, and they were evaluated by interview questionnaire and measurement of dental plaque index using Quigley-Hein index. Using SPSS ver. 18.0 for statistical analysis, paired t-test and Independent t-test were carried out for dental plaque index change and chi-square independence test for change between before and after oral health education. The result of this study revealed that the dental plaque index of the children showed significant decrease of 12% more in the experimental group (p<0.001). Both groups showed significant difference in knowledge about fluorine (p<0.05) and the percentage of correct answers showed significant increase in questions about bad food for teeth (p<0.05). In attitude toward oral health, the experimental group showed significant difference in every variable (p<0.05), and the control group showed significant difference in regular oral examination and frequency of toothbrushing (p<0.05). The experimental group showed significant result (p<0.05) with increase in the percentage of correct answers for the question about how to hold a toothbrush and decrease in the percentage of correct answers for the question about how to apply toothpaste, while the control group did not show significant difference in any variable. Therefore, Q-scan as an appropriate tool for motivation, provides effective educational methods in oral health education.