• Journal of Periodontal and Implant Science
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• 제53권4호
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• pp.269-282
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• 2023

Purpose: Dental fear hinders patients from receiving appropriate dental treatment. In particular, the noise generated by high-speed air turbines and ultrasonic scalers can adversely affect patients. Many efforts have been made to reduce the discomfort caused by noise, but no methods are definitively recommended. The purpose of this study was to determine the efficacy of active noise-canceling (ANC) headphones in reducing the pain and discomfort associated with dental scaling. Methods: Fifty-five patients requiring scaling and root planing, aged ≥19 years and showing no auditory problems, were included. Scaling was performed for the bilateral maxillary molars and premolars while patients wore headphones, with ANC turned either on or off. The degree of noise and pain reduction in the on and off conditions were surveyed using a visual analog scale (VAS). The Wilcoxon signed-rank test was performed to compare noise-and pain-related discomfort with ANC turned on and off. Results: The sample included 28 men and 27 women with a mean age of 45.45±13.12 years. The average noise-related discomfort score was 3.84±2.12 and 2.95±1.99 when noise-canceling was turned off and on, respectively, with a statistically significant difference (P<0.05). Similarly, the average pain-related discomfort score was 3.78h±2.00 and 3.09±1.96 when noise-canceling was turned off and on, respectively, which was a statistically significant difference (P<0.05). Conclusions: The use of ANC headphones seems to reduce the discomfort caused by noise and pain in patients undergoing scaling.

• 한국도로학회논문집
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• 제19권2호
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• pp.7-15
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• 2017

PURPOSES : Infiltration of moisture, polluted material, and deicer into concrete, accompanied by freeze and thaw can cause significant deterioration of concrete pavement. In order to protect concrete from deterioration, it is necessary to prevent the infiltration of these concrete external materials. The moisture-repellent agent, which is a surface treatment and maintenance material added to concrete structures to render them water resistant, has advantages such as prevention of water infiltration and security against air permeation. Nano-coat, which is referred to as silicon hydride, is typically used as a moisture-repellent agent. Therefore, in this study, an attempt is made to use penetration-type Nano-coat as an alternative in order to evaluate its applicability through environmental resistance tests. METHODS : This study aimed to evaluate the applicability of penetration-type Nano-coat, which can provide water repellency to concrete, in concrete pavements, through various environmental resistance tests such as freezing and thawing resistance, chloride ion penetration resistance, and surface scaling resistance tests. The applicability of penetration-type Nano-coat was demonstrated based on the specification of KS F 2711, KS F 2456, and ASTM C 672. RESULTS :In the case of penetration-type Nano-coat applied on sound concrete, an increase in concrete durability was demonstrated by the negligible chloride ion penetrability and the absence of scaling, as revealed by visual observation of the surface, after 50 cycles of scaling resistance test. In addition, test result of the application of penetration-type Nano-coat on deteriorated concrete established that concrete surface pretreated by grinding provided improved durability than non-treated concrete. CONCLUSIONS :This study indicates that penetration-type Nano-coat is applicable as an effective alternative, to increase the durability of concrete structures. In addition, it was known that pretreatment of deteriorated concrete surface, such as grinding, is required to improve the long-term performance of concrete pavement.

• 한국치위생학회지
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• 제14권1호
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• pp.33-38
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• 2014

Objectives : The purpose of the study is to investigate satisfaction, awareness and utilization of dental telephone services in dental clinic patients. Methods : A self-reported questionnaire was filled out by 220 dental clinic patients in G metropolitan city from March 11 to September 27, 2013. The data were analyzed by a descriptive analyses, ${\chi}^2$-test and relevant factors were determined using logistic regression analysis by SPSS 12.0. Results : The experience rate of scaling was 68.0% and the average number was $1.04{\pm}1.13$. The experience rate of regular check-up was 41.0% and the average number was $1.01{\pm}1.29$. Satisfaction and utilization rate of scaling and regular checkup was higher than that in those who did not receive the services. The major variables influencing the experience of scaling were woman, utilization of dental telephone service and regular check-up were awareness, utilization of dental telephone service and reason of utilization of dental telephone service(preventive). Conclusions : The dental telephone service in dental patients improved oral health. Accordingly, it is necessary to develop the professional dental hygiene program for oral health in dental patients.

• Journal of Periodontal and Implant Science
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• 제27권3호
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• pp.575-584
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• 1997

The quality of periodontal instrument cutting edge is a basic element of effective root planing procedure. Using instruments, the sharp edge is changed into blunt or beveled edge. With the blunt instrument, the periodontal treatment can't be carried into accuracy and effective. The study on the wear of periodontal curet is insufficient, there are few publications about the change of sharpness of cutting egde after using instrument and a certen reports were published on the study of scanning electron microscope(SEM) examination. In this study, to declare the number of strokes for sharpening of instruments, the changes of cutting edge is measured by the clinical methods, tactile sensitivity examination and refraction light-white line test after scaling strokes and root planing strokes. SEM test was added for defined the changes of cutting edges. The 7/8 Gracey curets that have been never used was tested. Maxillary molars which were extracted from the School of Dental Medicine, Dankook University was used. Subjected teeth had attachment loss more than 6 mm in bucca-lingual surface and sufficient calculus of a band type in cervical area. The strokes of curet were executed 3, 5, 7, 9, 11, 13 times on scaling stroke and 10, 15, 20, 25, 30, 35 times on root planing stroke. A resident has periodontal experience over 3 years carried out the clinical examinations those tactile sensitivity examination and refraction light-white line test 5 times. The case there being tactile sensitivity certenly is 2, the case being felt tactile sensitivity is 1, and the case there not being tactile sensitivity is 0. The visual examination was recorded as following. The case that refracted white line is not recognised is 2, the case that uncerten is 1, and the case that acknowledged is 0. The results were obtained as follows. 1. After scaling strokes, the tactile sensitivity was reduced after 11 strokes and disappeared in 13 strokes. 2. In tactile sensitivity after root planing procedures, sensitivity was reduced after 25 strokes and disappeared in 35 strokes. 3. In case of visual examination, the detection of refracted white line was increased after 9 strokes of scaling procedures and the accuracy of wear wasn't showed after root planing procedures. 4. In SEM, metal projection was observed on new periodontal curet cutting edge and it was disappeared after scaling procedures. 5. In SEM, the cutting edge was showed changing linear into an aspect of the surface after 5 strokes of scaling procedures and 10 strokes of root planing procedures and showed beveled edge in 11 strokes of scaling procedures, 25 strokes of root planing procedures. The results of 3-type examination indicated that the sharpening of curet should be performed after 11 strokes of scaling procedures and 25 strokes of root planing procedures.

• 콘크리트학회논문집
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• 제13권4호
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• pp.397-405
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• 2001

해안에 근접한 콘크리트 구조물이 동결음해 작용을 받을 경우, 내륙 콘크리트에 비해 내구성능 저하가 촉진된다. 그리고 최근 동절기에 차량의 안전 주행을 위해 도로 및 교량에 염화칼슘 등의 제설제의 산포량이 현격히 증가하고 있으며 이로 인해 내륙 콘크리트 구조물도 해안 콘크리트 구조물과 마찬가지로 동결융해와 염해의 복합작용에 의한 내구성능 저하가 염려된다. 미국, 일본 및 유럽 등에서는 제설제가 콘크리트에 미치는 영향에 대해 연구가 활발히 진행되고 있다. 그리고 제설제가 콘크리트에 미치는 영향을 검토하는 시험방법이 제정되었다. 그러나 우리 나라에서는 동결융해와 염해에 대한 복합 내구성능 저하시험방법은 제정되어 있지 않으며 또한 이에 대한 연구가 이루지지 않고 있다. 따라서 본 연구에서는 동결융해와 염해의 복합작용을 받는 콘크리트의 내구성능 저하를 평가하는 방법을 검토하기 위해 복합 내구성능 저하 실험을 실시하였다. 복합시험에서 시멘트 종류, 강도, 공기량 등이 스케링에 미치는 영향을 검토하였다. 그 결과, 염화물 존재 하에서 동결융해 작용을 받는 경우, 콘크리트의 스케링 손실이 촉진된다. 또한 스케링에 대한 저항성은 사용 시멘트 종류, 콘크리트의 강도, 공기량의 영향을 크게 받는다.

• 한국도로학회논문집
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• 제18권2호
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• pp.51-60
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• 2016

PURPOSES : The applicability of the mechanics-based similarity concept (suggested by Feng et al.) for determining scaled variables, including length and load, via laboratory-scale tests and discrete element analysis, was evaluated. METHODS: Several studies on the similarity concept were reviewed. The exact scaling approach, a similarity concept described by Feng, was applied in order to determine an analytical solution of a free-falling ball. This solution can be considered one of the simplest conditions for discrete element analysis. RESULTS : The results revealed that 1) the exact scaling approach can be used to determine the scale of variables in laboratory tests and numerical analysis, 2) applying only a scale factor, via the exact scaling approach, is inadequate for the error-free replacement of small particles by large ones during discrete element analysis, 3) the level of continuity of flowable materials such as SCC and cement mortar seems to be an important criterion for evaluating the applicability of the similarity concept, and 4) additional conditions, such as the kinetics of particle, contact model, and geometry, must be taken into consideration to achieve the maximum radius of replacement particles during discrete element analysis. CONCLUSIONS : The concept of similarity is a convenient tool to evaluate the correspondence of scaled laboratory test or numerical analysis to physical condition. However, to achieve excellent correspondence, additional factors, such as the kinetics of particles, contact model, and geometry, must be taken into consideration.

• 한국환경과학회지
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• 제29권1호
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• pp.15-23
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• 2020

The determination of soil characteristics is important in the simulation of rainfall runoff using a distributed FLO-2D model in catchment analysis. Digital maps acquired using remote sensing techniques have been widely used in modern hydrology. However, the determination of a representative parameter with spatial scaling mismatch is difficult. In this investigation, the FLO-2D rainfall-runoff model is utilized in the Yongdam catchment to test sensitivity based on three different methods (mosaic, arithmetic, and predominant) that describe soil surface characteristics in real systems. The results show that the mosaic method is costly, but provides a reasonably realistic description and exhibits superior performance compared to other methods in terms of both the amount and time to peak flow.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.261-262
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• 2009

우리나라에서 시멘트 콘크리트 포장에서 알칼리-골재 반응에 의한 파손이 보고된 후, 알칼리-골재 반응에 대한 대책 방안 수립이 연구되고 있다. 본 연구에서는 시멘트 콘크리트 포장에서 알칼리-골재 반응을 억제하기 위한 방법으로 프리믹스 방식으로 플라이애시를 전체 바인더 증량(시멘트 + 플라이애시)의 20%를 치환하는 방법을 적용하였다. 동결-융해 실험에서 공기량 3% 이하의 시편을 제외하고 모두 시편의 3사이클 후 상대동탄성계수는 90 %이상이었고, 스케일링 실험에서 50 사이클 후 무게 손실량이 1kg/$m^3$이하가 측정되어 내구성이 우수한 것을 알 수 있었다.

• 한국학교ㆍ지역보건교육학회지
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• 제13권1호
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• pp.55-64
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• 2012

Objectives: The purpose of this study was related factors of oral health of scaling patients in dental hygiene department. Methods: The sample consisted of 218 at the scaling practice room of dental hygiene department in D College from March to November 2011. Chi-square test was used to analyze the relation the oral health behavior or oral hygiene and oral health, and losistic regression analysis was performed to analyze the factors asociated with oral health. Results: Scaling patients was 43.6% of the male and 56.4% of the women. Their age group was 79.8% of the twenty. Lately they was smoking status 69.7%. Brushing three times a day, 55.8% in male and female were 74.0% with significant differences(p=0.019). Kind of toothbrush "normal" the response was the highest, 45.3% male, 62.6% women were significantly higher in women(p=0.012). Toothbrushing educational experienced 33.7% men, women's educational experience rate of 52.8% was significantly higher(p=0.006), use of oral hygiene products education experienced 15.8% of the men and women 27.6% had significant difference(p=0.049). Scaling experience is not in the Dental plaque index the number of "bad" was significantly higher(p=0.035), toothbrushing educational experience is not in the Dental plaque index the number of "bad" and significantly higher(p=0.008) and Gingival bleeding index was significantly higher(p=0.033). Use of oral hygiene products educational experience if you do not have the number of the Dental plaque index "bad" were higher(p=0.011). Gingival bleeding index, affecting demographic variables were smoking(p=0.024). Dental plaque index the influence of experience with oral hygiene products factors(p=0.044) and gingival bleeding index was influenced Toothbrushing of educational experience(p=0.029). Conclusion: The results reported here confirm the factors associated with the oral health were education of oral hygiene products factors and Toothbrushing experience.

• 한국도로학회논문집
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• 제18권1호
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• pp.63-72
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• 2016

PURPOSES : The use of roller-compacted concrete pavement (RCCP) is an environmentally friendly method of construction that utilizes the aggregate interlock effect by means of a hydration reaction and roller compacting, demonstrating a superb structural performance with a relatively small unit water content and unit cement content. However, even if an excellent structural performance was secured through a previous study, the verification research on the environmental load and long-term durability was conducted under unsatisfactory conditions. In order to secure longterm durability, the construction of an appropriate internal air-void structure is required. In this study, a method of improving the long-term durability of RCCP will be suggested by analyzing the internal air-void structure and relevant durability of roller-compacted concrete. METHODS : The method of improving the long-term durability involves measurements of the air content, air voids, and air-spacing factor in RCCP that experiences a change in terms of the kind of air-entraining agent and chemical admixture proportions. This test should be conducted on the basis of test criteria such as ASTM C 457, 672, and KS F 2456. RESULTS : Freezing, thawing, and scaling resistance tests of roller compacted concrete without a chemical admixture showed that it was weak. However, as a result of conducting air entraining (AE) with an AE agent, a large amount of air was distributed with a range of 2~3%, and an air void spacing factor ranging from 200 to $300{\mu}m$ (close to $250{\mu}m$) coming from PCA was secured. Accordingly, the freezing and thawing resistance was improved, with a relative dynamic elastic modulus of more than 80%, and the scaling resistance was improved under the appropriate AE agent content rate. CONCLUSIONS : The long-term durability of RCCP has a direct relationship with the air-void spacing factor, and it can be secured only by ensuring the air void spacing factor through air entraining with the inclusion of an AE agent.