• Journal of Oral Medicine and Pain
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• v.48 no.4
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• pp.144-151
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• 2023

Purpose: The aim of this study was to assess the repeatability of the electrical measurement of taste detection on different dates and in different sessions in healthy young females. Methods: The sites of electrical stimulation were the tip of the tongue, the posterolateral border of the tongue and the soft palate on the right side unilaterally. The measurements were repeated over three consecutive days, three sessions per day and three times for each session in seventeen healthy females. The repeatability of the measurement was assessed by the intraclass correlation coefficient (ICC). Results: In the dB unit, the ICC of the tip of the tongue and the soft palate was good (61.03 and 66.03, respectively); however, the lateral border of the tongue was a little lower (58.07). In the ㎂ unit, all three test sites had poor ICC. Variability was more significantly associated with the subject factor than with other factors such as trials, sessions and days in dB and ㎂ units. Conclusions: Electrogustometry, which measures electrical taste detection thresholds in the dB unit, is repeatable and acceptable for clinical use in assessing taste function in healthy young females.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.1
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• pp.75-87
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• 2006

The purpose of this study was to investigate the effects of prostheses misfit, cantilever on the stress distribution in the implant components and surrounding bone using three dimensional finite element analysis. Two standard 3-dimensional finite element models were constructed: (1) 3 ITI implant supported, 3-unit fixed partial denture and (2) 3 ITI implant supported, 3-unit fixed partial denture with a distal cantilever. variations of the standard finite element models were made by placing a $100{\mu}m$ or $200{\mu}m$ gap between the fixture, the abutment and the crown on the second premolar and first molar. Total 14 models were constructed. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the distal marginal ridge of the distal molar. von Mises stresses were recorded and compared in the crowns, abutments, crestal compact bones, and trabecular bones. The results were obtained as follows: 1. In the ITI implant system, cement-retained prostheses showed comparatively low stress distributions on all the implant components and fixtures regardless of the misfit sizes under vertical loading. The stresses were increased twice under oblique loading especially in the prostheses with cantilever, but neither showed the effects of misfit size. 2. Under the oblique loading and posterior cantilever, the stresses were highly increased in the crestal bones around ITI implants, but effects of misfit were not shown. Although higher stresses were shown on the apical portion of trabecular bones, the effects by misfit were little and the stresses were increased by the posterior cantilever. 3. When the cement loss happened in the ITI implant supported FPD with misfit, the stresses were increased in the implant componets and supporting structures.

• Journal of Technologic Dentistry
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• v.37 no.3
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• pp.169-178
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• 2015

Purpose: This study was to investigate usage satisfaction of multi type handpiece with equipped air-jet function Methods: The subjects of this study through the survey was conducted for fifty-nine dental technicians in Daegu and Gyeongsangbukdo from the May 7 to 19, after the June 23 to July 4 2014. The survey was about the function and quality through user testing environment by cutting zirconia specimens using appliance for zirconia. The collected date was analyzed by the statistical program SPSS Win Ver 19.0 for the satisfaction of handpiece and control system. To test for significance on each item, p<0.05 had been decided a standard. General characteristics and relationship between the handpiece and control system was performed correlation analysis. Results: The results of this study is as follows. 35 dental technicians had 1~2 years career in zirconia part as the highest 59.3%, 95% of subjects expected that the prospects for the zirconia material have bright prospects. The satisfaction of multi type handpiece and control system design and function showed a significant difference. Subjects satisfied with the design and function of the multi type showed negative correlation with those of Standard. The satisfaction of multi type handpiece showed 3.37 points of air jet, 3.05 points of noise level, 2.69 points of water flow rate, and 1.98 points of cruise function. Sample differences in all parameters showed a statistically higher difference. Conclusion: High-speed cutting mechanism of multi-type is recommended working with zirconia materials and the multi-type unit combined handpiece motor, air-turbine and air-gun will be expected the increase of user due to the high satisfaction of air jet.

• Osong Public Health and Research Perspectives
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• v.9 no.6
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• pp.340-347
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• 2018

Objectives: The aim of this research was to determine intra-oral factors that affect halitosis in young women. Methods: This study was performed between March 2014 to May 2014, and included 35 women in their 20s with good oral health. Correlation and logistic regression analyses were performed to investigate the change in halitosis immediately, and 1 hour after scaling. Results: In both oral gas (OG) and extraoral gas (EG) groups, halitosis was reduced after scaling compared to before scaling. The logistic regression analysis of oral state factors in OG showed that as oral fluid [odds ratio (OR) = 0.792, p = 0.045] and dental plaque (OR = 0.940, p = 0.016) decreased by 1 unit, the OR in the OG group decreased (> 50). In addition, as glucose levels in the oral cavity (OR = 1.245, p = 0.075) and tongue coating index (OR = 2.912, p = 0.064) increased by 1 unit, the OR in the OG group increased (> 50). Furthermore, in the EG group, as oral fluid (OR = 0.66, p = 0.01) and dental plaque (OR = 0.95, p = 0.04) decreased, the OR in the EG group decreased (> 50) significantly. Conclusion: To control halitosis, it is necessary to increase oral fluid and decrease the amount of tongue plaque. Furthermore, maintaining a healthy oral environment, aided by regular scaling and removal of dental plaque, may significantly control halitosis.

• Journal of Korean Dental Hygiene Science
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• v.5 no.2
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• pp.145-153
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• 2022

Background: The purpose of this study was to analyze the association between the Geriatric Oral Health Assessment Index (GOHAI) and Quality of Life (QoL) between urban and rural residents in Koreausing data from the Korea Longitudinal Study of Aging (KLoSA). Methods: This study was analyzed using the SPSS 20.0 program (IBM SPSS Statistics), and a t-test was performed for difference between GOHAI and QoL, and a multiple regression analysis was used for association between the independent and dependent variables with confounding variables corrected. The statistical significance was p<0.05. Results: Urban residents' average QoL was statistically significantly higher rural residents'(Table 1, p>0.05). For subjects under the age of 65, the QoL increased by 0.30 points for urban residents and 0.39 points for rural residents according to GOHAI increased by one unit (Table 2, p>0.05). Also, for subjects aged 65 years or older, the QoL increased by 0.42 points for urban residents and 0.61 points for rural residents according to the GOHAI, increasing by one unit (Table 3, p>0.05). Conclusion: Through the results of this study, the quality of life of rural residents was lower than that of urban residents. The GOHAI had a stronger impact on QoL among rural residents than in urban areas. In order to address the disparity in QoL between urban and rural residents, it was believed that policies aimed at improving oral health for rural residents should b etaken in to account.

• The Journal of the Korean dental association
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• v.48 no.12
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• pp.893-918
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• 2010

This article is purposed of reviewing the development history of Japanese dental devices and instrument, and their related advertisement activities during the Japanese colonized period in Korea in early 20th century. Japanese dental devices and instrument were redesigned to accommodate their ergonomic shape above the simple imitation, and it implies the excessive desires brought them frustrations. The tragic earthquake on Sep. l, 1923, medical insurance law enforcement on Jan. 1, 1927, celebration of "Cavity prevention Day" started on Jun. 4, 1928, and the attack of Manchuria and China by Japan after 1931, all of these historical incidents become the preliminary requirement for the development of dental devices. On Nov. 1, 1937, Japanese government started to control dental materials, driving the campaigns for excluding foreign products and encourging the use of local products. In 1939, Nakajima dental manufacturers used this political and social atmosphere on their advertisement as saying "Our Nakajima's products have no compromise with the short raw materials, but only commitment to our quality". Since after 1940, the price and supply have been strongly under control, and the control group was appeared to manage all of supply and distribution of raw materials, regular price system, and specifications. At last, the Japanese national power were devastated in its production and distribution capacities, and get to the frustrated period. The main advertised dental devices and instruments in Korea during the Japanese colonized period were 1) dental chair, unit and cabinet, 2) dental x-ray, 3) compressors, 4) dental needles, 5) small instrument and carryon medical(emergency) kit, 6) oral hygiene and pyorrhea alveolaris, infrared rays, sunlight lamp, ultrashort wave treatment devices, 7)crown former, electric furnace, casting machine, articulator, electric lathe, and laboratory equipments, etc.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.10
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• pp.656-664
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• 2017

This paper presents the design and fabrication of a high power piezoelectric ultrasonic surgery unit for multi-purpose dental implantation. A conventional piezoelectric ultrasonic surgery units consists of a transducer and a tip. However, the drawback of this simple structure is that the output performance of the transducer considerably changes with the change of the tips. An ultrasonic surgery unit that has an additional booster between the transducer and the tip can solve this problem to some extent; for this, an optimal structural design for the transducer is required. We used the Bolted Langevin Transducer (BLT) as the basic transducer; it consists of piezoelectric ceramics and a metal body. It's structure was optimized using mathematical methods to determine the length and radius of the tail and head masses. Additionally, the booster was also subjected to the same methods. Using these mathematical methods, optimal results in terms of the resonance frequency (24.96 kHz), displacement ($14.27{\mu}m$), and pressure (2.8 MPa), could be obtained. The validity of this proposed surgery unit was confirmed experimentally, exhibiting a cutting force of around 7% higher than that of a conventional surgery unit.

• Journal of Korean society of Dental Hygiene
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• v.13 no.1
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• pp.166-173
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• 2013

Objectives : The purpose of this study was to survey some soldiers oral care products along recognition, and thereby to identify possible correlations among those factors. Methods : Questionnaire survey was carried out targeting 272 soldiers. The collected data was performed frequency & percentage, fisher's exact test, chi-square test and multiple regression analysis. Results : Respondents approving the implementation of water fluoridation were 50.5%. The general factors of approval were age, education, Monthly household income. The knowledge factors of approval were experience of hearing of this program, the knowledge of the purpose of this program, the knowledge of the some regions in South Korea had been implement water fluoridation. The results of multiple logistic regression analysis were the awareness of oral health and the knowledge level of water fluoridation were related with this program approval. Conclusions : The study suggest that oral care products should be include in military dental health care program. In addition to development dental health programs each military unit is dental health care between Korean soldiers.

• Journal of Technologic Dentistry
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• v.23 no.1
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• pp.45-53
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• 2001

This study was performed to investigate the effect of vent on the marginal discrepancy of PFM base metal castings. Eighteen identical wax patterns of a maxillary 3 unit anterior bridge were fabricated. Nine cases out of them were vented with $\phi$2.5mm sprue wax, for direct comparison as to the marginal discrepancy of the castings with the other non vented 9 ones. The mean value of marginal discrepancies of the vented castings was $85.02{\pm}25.57{\mu}m$, and that of the non vented was $163.21{\pm}69.88{\mu}m$ respectively. Statistical analysis revealed that marginal discrepancy of the vented casting was significantly reduced(p<0.05).

• The korean journal of orthodontics
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• v.46 no.1
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• pp.36-41
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• 2016

Objective: The aim of this study was to evaluate retention practices commonly employed by orthodontists. The objectives were to identify the types of retainer frequently used and to investigate the variations in retention practice. Methods: A total of 97 orthodontists were randomly selected, and a questionnaire consisting of 25 multiple-choice questions sent to them by mail. Upon receiving of the completed questionnaires, the data were statistically analyzed. Results: A total of 32 responses were received; among these, 59.4% of orthodontists' practiced is in a government setting and 40.6% were in private practice. A vacuum-formed retainer was the most commonly used removable retainer for both maxillary (46.9%) and mandibular (46.9%) arches, followed by a Hawley retainer (maxilla, 43.8%; mandible, 37.5%), and a fixed retainer (maxilla, 3.1%; mandible, 9.4%). Of the responding orthodontists, 78.1% prescribed full-time wear (more than 20 h per day) for a duration of 3-9 months for a maxillary arch, compared to 71.9% for the mandibular arch. Only 18.8% of the orthodontists prescribed part-time wear of the retainer for the maxillary arch, compared to 21.9% for the mandibular arch. The majority of orthodontists did not instruct their patients to stop wearing removable retainers (71.9%) or fixed retainers (66.8%) at any specific time and they preferred their patients to continue wearing retainers. Conclusions: Vacuum-formed retainers are the most commonly used retainers among orthodontists. The majority of orthodontists prescribed full-time wear for more than 20 h per day with a duration of 3-9 months and preferred indefinite use of the retainer.