• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.559.1-559
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• 2001

The aim of the study was to determine the direction and the rate of polymerization shrinkage of light-cured resin composite. Materials and Methods: A microfocus x-ray CT(computed tomography) instrument (SMX-255CT, Shimadzu Co., Kyoto, Japan) was used to analyze and characterize the pre-and post-gel phases. A microfocus x-ray tube was used to enable a focus dimension of 4 microns.(omitted)

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.990-995
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• 2012

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

• 대한치과보철학회지
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• 제35권3호
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• pp.504-516
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• 1997

Ultrasonic instruments transfer electrical energy to mechanical energy resulting in vibration used for various dental treatments. If we could know the effect of ultrasonic instruments on the dental cements within the cast crown, we could take care when conducting periodontal surgery and when using the ultrasonic instrument to remove cast crown, it would be much more convenient. The purpose of this study was to compare the bond strength of several dental cements according to ultrasonic instrumentation time. In this study 4 types of cements were used to cement the specimens. they were treated with ultrasonic instrumentation for 0-5 minutes and the change in bond strength were statistically compared. The results were as followed. 1. The tensile bond strength of zinc phosphate cement decreased according to the increase in time of ultrasonic instrument and showed significant difference between 0 minutes and the others and between 1 minute and 2,3,4,5 minutes (p<0.05). 2. The tensile bond strength of polycarboxylate cement decreased according to the increase in time of ultrasonic instrument and showed significant difference between 5 minutes and the others and between 4 minutes and 0 minutes (p<0.05). 3. The tensile bond strength of zinc phosphate cement decreased according to the increase in time of ultrasonic instrument and showed significant difference between 5 minutes and the others (p<0.05). 4. The tensile strength of resin cements showed no statistically differences according to the ultrasonic instrumentation time. In conclusion, it is considered that zinc phosphate cements is most affected by ultrasonic instrumentations and resin cement is the least affected. When using ultrasonic instruments the result avove should be used as an index.

• 한국치위생학회지
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• 제14권2호
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• pp.251-259
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• 2014

Objectives : The purpose of the study was to investigate the overall research trend and change in dental fear during 9 years(2004-2012) and to identify the major outcomes and future directions to research. Methods : Descriptive literature review was conducted for dental fear in Korea. The research setting should be elementary, middle, high schools and adults. Results : In this study, the literature review of the most used tools to measure fear was that DFS. The most commonly used instrument was Dental Fear Survey(DFS) in the literature review. The number of dacayed tooth was proportional to subjective fear and anxiety. The indirect experience of dental pain was heard from family and friends. So the fear caused the patients to have negative bias toward dental treatment. The negative reliability towards the dentist increased the dental fear to the patients. Conclusions : Through the literature review, dental hygienists are able to understand the dental fear of the patients.

• Journal of Dental Anesthesia and Pain Medicine
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• 제22권4호
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• pp.267-275
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• 2022

Background: Various instrument kinematics used in single-visit endodontics influence the occurrence of pain after endodontic therapy. This study aimed to evaluate the occurrence of pain after mechanical instrumentation with Hyflex EDM (HEDM) and WaveOne Gold (WOG) during single-visit endodontic therapy. Methods: Sixty patients diagnosed with asymptomatic irreversible pulpitis and normal apical tissues in mandibular premolar teeth were included in the study for single-visit root canal therapy. The patients were divided into two groups (n = 30) according to the rotary instrument used during root canal preparation (group A [HEDM] and group B [WOG]). Pain was evaluated after endodontic therapy at 8, 24, and 48 h intervals using the visual analog scale (VAS). Data obtained were analyzed using the chi-square test, independent t-test, MannWhitney U test, and Wilcoxon matched-pairs test. Results: Statistically significant differences were observed between the two groups (P < 0.001) at 8, 24, and 48 h, with WOG exhibiting less pain than HEDM files. Conclusion: Postoperative pain was lower in the WOG file system than in the HEDM file system after single-visit root canal therapy at 8, 24, and 48 h.

• 한국치위생학회지
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• 제11권1호
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• pp.137-148
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• 2011

Objectives : The objectives of this study were to investigate the infection control practices of practicing dental hygienists. Methods : This research was based on self-filling survey which 149 dental hygienists in dental clinic and dental hospital on October 2009. For the data analysis, an SPSS WIN 11.5 program was used and its signification level was 0.05. The following shows the results of this study. Results : 1. There was significant difference in there practice about sterilization and disinfection of dental instrument depending upon the respondent' career(p<0.05). 2. There was significant difference to were gloves and a apron according to type of service(p<0.05). 3. There was significant difference in the time to change the gown according to experience of education factors infection control(p<0.05). Conclusions : The majority of dental hygienists surveyed reported altering infection control practices and treatment techniques. While there has been an improvement in compliance with recommended infection control guidelines. Even though there is a need for continuing infection control education for dental hygienists.

• 치위생과학회지
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• 제14권2호
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• pp.264-268
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• 2014

There are a lot of dental emergency situation. Especially on disabled or pediatric patient with negative behavior, accidental aspiration or ingestion of foreign body (ex: dental instrument) is one of the common accidents in dental procedure. Dentists and dental hygienists must have knowledge about the precaution and be ready to deal with foreign body aspiration during dental treatment, especially on the disabled. This is a case of an accident during the dental treatment of 14-year-old female patient with cerebral palsy. During scaling, prolonged retained primary tooth which had resorbed roots was fell into left bronchi. So we tried to remove the crown by endotracheal approach. Most ingested foreign bodies pass through the gastrointestinal tract spontaneously, but some of them need endoscopic or surgical removal. Moreover aspiration into broncho-trachea can be more serious events and must be treated as emergency situation.

• 구강회복응용과학지
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• 제22권2호
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• pp.173-180
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• 2006

Objectives The aim of this study is to compare the quality of root canal preparation completed using MFile-$System^{(R)}$ instrument ( Komet, Gebr.Brsaseler, Germany) and conventional stainless steel file in the canals of Maxillary molar teeth that had a canal curvature between $25^{\circ}$ or more Materials & Methods Buccal canals of 24 first and second maxillary molar teeth, extracted for periodontal and prosthetic reasons were used. Tissue fragments and calcified debris were removed from teeth by scaling and the teeth were stored in 10% formalin solution for 24 hour. Then, teeth were stored in saline until used. To be included the roots had to have completed formed apices and angle of curvature ranging between $25^{\circ}$ or more according to the criteria described by Schneider(1971). Palatal and Second mesiobuccal canals were not included. Teeth were embedded into transparent acrylic. The teeth were randomly divided into two experimental groups. All teeth were scanned by Dental CT (PSR9000N, Asahi, Japan) to determine the root canal shape before instrumentation. Image slices were prepared from the apical end point to the pulp chamber. The first two sections were 2 mm from the apical end of root and 2 mm below the orifice. Further section was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. 12 teeth were instrumented using stainless steel fileand another 12 teeth were instrumented using MFile-$System^{(R)}$. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross sectional images taken prior to canal preparation. Amount of transportation and centering ability was assessed. Student's t-test was used for statistical analysis. Result Less transportation occurred with MFile-$System^{(R)}$ rotary instrumentation than stainless steel instrument. MFile-$System^{(R)}$ had better centering ability than stainless steel instrument. Conclusion MFile-$System^{(R)}$ rotary instrumentation transported canals less and had good centering ability.

• 한국치위생학회지
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• 제16권3호
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• pp.347-353
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• 2016

Objectives: The purpose of the study is to investigate the dental fear and related factors of dental hygienists using dental fear survey. Methods: A self-reported questionnaire was completed by 279 dental hygienists from January 15 to March 28, 2015. The study instrument was dental fear survey. Data were analyzed using SPSS 19.0 program by t-test, one way ANOVA and stepwise multiple regression analysis. The questionnaire included general characteristics of the subjects, subjective oral health status, use of dental care services, subjective oral health status, and recent dental treatment. Results: Alcohol consumption was the most influential factor to the dental fear. The subjective status of oral health and direct pain sense also contributed to the dental fear. Conclusions: To reduce the dental fear, it is important to have high confidence toward the dental treatment performance in the dental hygienists.

• 한국치위생학회지
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• 제7권3호
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• pp.329-342
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• 2007

This study was conducted in order to know whether DFS questionnaire which can measure dental fear is suitable for dental fear measuring method and to know effect of dental fear on dental use behavior and treatment need degree. This survey was conducted from May 1, 2007 to May 31, 2007. A total of 281 surveys eligible among all the collected surveys were used in the analysis. Collected data were analyzed by using SPSS 12.0. The obtained results were as follows: 1. Based on the reliability analysis, we concluded that the questionnaire of dental fear was reliable, and the Cronbach' s alpha coefficients of the all subscales were more than 0.6. 2. Among the dental fear of 3 factors, treatment fear cause stimulation factor was higher than the others. Most of all, following two situations(when preparation was made and when people hear dental instrument operating sound) are the highest in the treatment fear. And women are higher than men in every item. 3. In the Dental treatment need degree caused by dental fear degree, high fear group was $4.76{\pm}1.954(M{\pm}SD)$ which was higher than that of low fear group.(low fear group was $4.07{\pm}2.184(M{\pm}SD)$. In conclusion, dental fear and dental treatment need degree are related each other.