• Journal of dental hygiene science
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• v.14 no.3
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• pp.319-324
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• 2014

The aim of this study was to evaluate influences of titanium dioxide ($TiO_2$) concentrations and irradiation times on growth of Streptococcus mutans when irradiated by visible light (405 nm wavelength) and by ultraviolet light (254 nm wavelength). To find the optimal antibacterial concentration of $TiO_2$, 0.01, 0.1, 1.0, and 10.0 mg/ml $TiO_2$ suspension was prepared with sterilized distilled water. S. mutans cultured media was added to $TiO_2$ solution to set the final cell count to $10^4CFU/ml$. The photocatalytic reaction was induced by irradiating 254 nm and 405 nm lights for 10 minutes. To compare the bactericidal activities according to irradiation times, all photocatalytic reaction was carried out with 0.1 mg/ml $TiO_2$ for 0, 10, 20, 30, and 40 minutes with both lights. After the photocatalytic reaction, $100{\mu}m$ of the reaction mixture was immediately plated on brain heart infusion agar. These plates were placed at 5% $CO_2$, $37^{\circ}C$, for 24 hours and the bacterial colonies were counted. All experiments were performed in quintuplicate. One-way ANOVA was used to determine whether there were any significant differences between the $TiO_2$ concentrations or the irradiation times. The most effective concentration of $TiO_2$ for its photocatalytic bactericidal effect on S. mutans was 0.1 mg/ml when irradiated with 254 nm and 405 nm lights. The longer the irradiation time, the bigger the bactericidal effect for both wavelengths. Over 99% of bacteria in the inoculum were killed after irradiation with 254 nm for 20 minutes and with 405 nm for 40 minutes. In conclusion, a photocatalytic reaction of $TiO_2$ induced by visible light of 405 nm constitutes the bactericidal effect on S. mutans.

• Journal of dental hygiene science
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• v.6 no.3
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• pp.159-162
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• 2006

This study examined the relationship between the quantity of Streptococcus mutans and Lactobacillus spp. related to dental caries and the degree of acidity in saliva. A total of 240 saliva samples were taken from 80 subjects at the faculty of dentistry in Skopje, Macedonia. The saliva samples were taken by stimulating saliva production stimulation with paraffin chewing. However, no stimulation was applied when obtaining the samples used for measuring the pH. The data showed that in the caries group, S. mutans in 1 ml of saliva formed colonies with confluent growth (CFU > $10^6$ and $10^4-10^5$) in 100% of samples, whereas the Lactobacillus spp. formed colonies with confluent growth in 78.3%. In contrast, no colonies with confluent growth (CFU > $10^6$ and $10^5$) were found in the control group (with healthy intact teeth). In the caries group, the pH of the saliva was slightly acidic (pH = 5.90 - 6.50) and the buffering capacity was very low (below 0.7 ml of saliva per min). On the other hand, the pH of the saliva in the control group was neutral (pH 7.01 - 7.7) and the buffering capacity was high (over 1 ml of saliva per min). The increased number of S. mutans and Lactobacillus spp. in 1 ml of saliva (above $10^5$ CFU or more) from the CRT (Caries Risk Test, Vivadent, Liechtenstein) bacteria test can indicate an increased caries risk as well as slightly higher acidity of the saliva. Overall, these results reveal that the caries risk can be predicted by simply measuring the pH and buffering capacity of saliva, and can be used to monitor the effect of dental hygiene practices with the aim of preventing dental caries.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.272-283
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• 2016

This study compared and analyzed the occluding effects of fluoride compounds and desensitizers, which are commonly used in dental clinics, on dentinal tubules. This study also evaluated the persistence of the active ingredients over time by performing toothbrushing with an electric toothbrush. Thirty-five molar teeth, which had been extracted within the past 3 months from healthy people without tooth decays, amalgam fillings, or dental crowns, were divided into 4 pieces each. Of these, 135 teeth pieces were used as study specimens. These specimens were divided into a control group, an untreated group, and 5 experimental groups (acidulated fluoride gel, fluoride varnish, Gluma, Super Seal, and SE-Bond). The specimens were then subjected to toothbrushing equivalent to 1 week (140 times), 2 weeks (280 times), and 4 weeks (560 times), and the occluding effects on dentinal tubules in 3 regions of each specimen were examined under a scanning electron microscope. The fluoride varnish treated group showed the highest degree of dentinal tubule occlusion effects during the first, second, and fourth weeks of toothbrushing, with the SE-Bond treated group showing the second highest degree and the Gluma treated group showing the lowest degree. After 4 weeks of toothbrushing, the Gluma treated group and the Super Seal treated group showed the lowest degrees of dentinal tubule occlusion effects. In summary, the fluoride varnish treated group and the SE-Bond treated group displayed higher occlusion effects even after 4 weeks of treatment than did the other experimental groups. Therefore, it is the authors' belief that fluoride varnish and SE-Bond are effective for treating dentinal hyperesthesia.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.1-17
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• 1998

두개의 임플랜트로 지지되는 overdenture를 이용한 하악무치악환자의 치료법은 경제적이면서, 실용적인 치료로 인정을 받고 있다. 하지만 해부학적인 조건으로 임플랜트를 설측 혹은 후방에 식립해야 되는 경우에는 일반적인 bar설계는 bar가 구강저 상방을 지나게 되어 혀운동, 발음, 위생관리 등에 많은 문제점을 부여한다. 이에 대한 해결방법으로 전방부 치조제 상에 보철물의 회전을 허용하는 angular bar를 설계할 수 있다. 하지만 이 설계는 임플랜트에 불리한 moment를 유발한다. 그럼에도 불구하고 뛰어난 유지력과 지지능력, 경제적인 면 때문에 angular bar는 임상에서 많이 사용되고 있다. 이에 본 연구는 angular bar의 전방 cantilever양을 달리하여 임플랜트 및 주변조직에 미치는 영향을 삼차원 유한요소분석법을 통해서 알아보고자 하였다. 이공사이의 하악골을 단순화시킨 준하악골모형에 직경 3.75mm인 브로네마르크 임플랜트 2개를 길이가 13,15mm인 경우로 설정하여 제 1소구치 부위에 식립하였다. 두 임플랜트를 연결하는 bar는 전방부 cantilever양을 0-5mm, 1mm씩 하여 6가지 경우를 가정하고 제작하였다. 각각 bar 중앙부에 수직압 (90도) 35N, 경사압(120도) 70N, 수평압(0도) 10N을 가하였으며 이때 나타나는 응력 분산형태와 임플랜트의 골유착에 불리하게 작용하는 최대주응력(인장력)과 변위량을 살펴보았다. 연구결과 다음과 같은 결론을 얻었다. 1. Cantilever양이 증가할수록 주변피질골과 임플랜트로 응력이 집중되었으며 상부 보철물의 변위량도 커졌다. 2. Cantilever양에 대한 수평압의 영향은 크지 않았으며 임플랜트 길이가 긴 것이 변위량과 응력이 작았다. 3. 경사압에 대한 응력의 변화는 cantilever양의 증가에 따라 급격히 증가하는 양상을 띠었으며 임플랜트길이가 응력 및 변위의 양에 미치는 영향은 없었다. 4. 수직압에 대한 응력의 변화는 초기에는 완만한 증가를 보이다가 일정 시점 지난 후에는 증가율이 커지는 경향을 띠었다. 증가현상이 두드러지기 전에는 길이의 증가가 응력의 분산효과는 가져왔으나 이후에는 길이의 응력분산 효과는 없었다. 5. 응력분포양상은 cantilever양이 증가할수록 골조직을 통한 분산정도는 작아지고 특정부위의 피질골과 임플랜트, 상부보철물에 집중되는 경향을 보였다. 6. 임플랜트와 주변 골조직으로의 응력분산능력이 예후를 좌우한다는 점에서 angular bar는 적합치 못하며 부득이한 경우는 임플랜트 길이를 길게 하고 최대한 3mm이내로 cantilever양을 제한하는 것이 추천된다.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.563-576
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• 2012

목적 : 본 연구는 업무형태에 따른 측두하악장애의 유병률과 업무 시 노출되는 직무스트레스 및 구강 내 악습관이 측두하악장애와 어떠한 연관성이 있는지 알아보아 보건학적 기초자료를 제공하고자 실시되었다. 방법 : 본 연구의 자료 수집을 위하여 서울과 경기 일부지역에 근무하고 있는 일반사무직, 서비스직, 교직원으로부터 편의 추출된 452명을 대상으로 2010년 1월부터 2010년 4월까지 설문조사를 실시하였고, 수거된 353명을 연구대상으로 하였다. 설문지는 측두하악장애의 증상, 하악사용에 관한 구강 내 악습관, 직무스트레스, 인구사회학적 특성으로 구성되었다. 측두하악장애의 증상의 정도를 구분하기 위해 설문지의 양성응답 수의 빈도에 따라 무증상인 1단계에서 양성응답 수가 가장 많은 4단계 까지 총 4그룹으로 나누었다. 측두하악장애의 유병률을 알아보기 위하여 빈도분석을 시행하였고, 측두하악장애의 증상의 정도에 따른 여러 요인들 간의 연관성 및 관련요인을 알아보기 위하여 교차분석 및 경향성 분석과 다항로지스틱회기 분석을 시행하였다. 결과 : 측두하악장애의 유병률은 75.4%였고, 측두하악장애에 대한 주관적 증상으로는 관절잡음이 56.4%로 가장 주된 증상 중 하나였으나 남녀 간의 차이는 통계적으로 유의하지 않았다. 다음으로는 두통이나 목의 통증이 36.5%이었고, 귀, 관자놀이, 볼 주위의 통증이 22.1%로 높았다. 측두하악장애의 주관적인 증상 수에 따른 인구사회학적 특성은 증상이 없는 경우 여성에서 19.1%, 남성에서 36.6%로 여성에서 더 높은 유병률을 보였다. 연령별로는 40세 이상의 그룹보다 20 - 30대그룹에서 측두하악장애 증상수가 높아지는 경향을 보였다. 하악 사용과 관련된 악습관 및 직무스트레스는 측두하악장애 증상수와 유의한 관련성이 있는 것으로 나타났는데, 하악 사용과 관련된 습관의 개수가 많아질수록 측두하악장애의 증상의 개수도 많아졌고, 습관이 한 가지씩 늘어날수록 측두하악장애 증상이 없는 1단계보다 3단계가 될 위험이 1.45배, 4단계가 될 위험이 1.57배 높아졌다. 스트레스 수준도 가장 하위단계에서 한 단계 높아지면 측두하악장애 1단계에서 4단계가 될 위험이 2.49배, 두 단계 높아지면 3.43배 높아졌다. 결론 : 본 연구의 결과 측두하악장애와 업무특성에 따른 연관성은 설명하지 못하였지만, 직무스트레스가 높은 경우 측두하악장애 증상의 개수 또한 높아짐을 확인할 수 있었다. 이는 측두하악장애의 주관적인 증상을 발생시키는데 있어서 업무형태 보다는 심인적인 부분이 더 중요한 인자임을 의미한다. 그러므로 측두하악장애 평가 시 신체적인 문제뿐 아니라 행동적, 심리 사회적 문제로 예측인자를 폭넓게 인식함으로써 다각적인 접근을 하는 것이 필요하며, 측두하악장애 증상이 발생된 경우 임상적 치료뿐 아니라 행동요법 및 심리 치료와 자가 관리 등이 함께 수반되어 기여요인 조절을 조절하는 것이 중요하다 하겠다.

• Journal of Korean society of Dental Hygiene
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• v.13 no.1
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• pp.21-29
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• 2013

Objectives : The purpose of this study was to examine the participation attitude of students toward pre-clinical practicums, their satisfaction with the practicums and related stress, and to investigate the influential factors for their participation attitude to practicums. Methods : The subjects in this study were three different groups of students who took pre-clinical practicums at different times. One group of students who entered college in 2008 took a practicum in December, 2009, and another group of students who entered college in 2009 took a practicum in June, 2010. The third group of students who entered college in 2010 took a practicum in June, 2011. Results : 1. As for participation attitude, the students who completed a practicum before they underwent field training in the second semester of their sophomore year got a higher mark of 3.44(p<0.05). 2 Concerning the operation of practicum, they felt a lot of stress when they took a practicum before they underwent field training in the first semester of their sophomore year and when they had no dental experience(p<0.001). 3. Regarding satisfaction with practicum, they scored higher when they took a practicum before they underwent field training in the second semester of their sophomore year(p<0.05). And the students who were more gratified with dental experience expressed better satisfaction(p<0.001). 4. As to the influential factors for the participation attitude of the students, those who were more satisfied with the content of practicum, the operation of practicum and evaluation took a more positive participation attitude(p<0.001). More stress about the operation of practicum and more stress about evaluation exerted a greater negative influence on participation attitude(p<0.05). Conclusions : Given the findings of the study, a pre-clinical practicum should be offered before field training is provided in the second semester of the sophomore year in order to ensure the efficiency of education, and a wide variety of information should be offered so that students could gain dental experience before they take a practicum.

• Journal of Korean society of Dental Hygiene
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• v.23 no.4
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• pp.219-226
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• 2023

Objectives: This study aimed to investigate the effects of rhubarb extract on osteoclast differentiation in bone marrow-derived macrophages (BMMs). Osteoclasts are vital for bone resorption and remodeling. Osteoclast dysregulation can contribute to various bone-related disorders that directly affect oral health. Rhubarb, a medicinal plant with anti-inflammatory properties, has been shown to modulate bone metabolism. Methods: BMMs were isolated from the femurs and tibias of 5-week-old C57BL/6 mice and cultured in the presence of mouse macrophage colony-stimulating factor (M-CSF) for 3 days. Subsequently, BMMs were treated with M-CSF and receptor activator of nuclear factor-κB ligand (RANKL) to induce osteoclast differentiation. Results: Rhubarb extract effectively suppressed osteoclast differentiation in BMMs. Furthermore, rhubarb extract inhibited the mRNA expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK), which are essential for osteoclastogenesis. Moreover, it inhibited the RANKL-induced expression of nuclear factor of activated T cell c1 (NFATc1), a crucial transcription factor in osteoclast differentiation. Conclusions: These results suggest that rhubarb extract promotes oral health by inhibiting osteoclastogenesis in BMMs. Thus, rhubarb extract shows promise as a therapeutic agent for bone-related disorders that directly affect oral health, particularly those associated with abnormal osteoclast activity. Further research and exploration of the underlying mechanisms are warranted to fully understand their potential clinical applications.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.227-236
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• 2016

Periodontal disease, one of the most common oral diseases, has been widely researched. However, in the face of increasing incidence of adolescent periodontitis, there has been only little concern about the periodontal conditions in adolescents. The purpose of this study was to evaluate the periodontal health and assess the prevalence of the periodontal disease and its causing factors among adolescents. The data was collected from subjects ranging from age 10, 13 and 16 years old in Jeonju by clinical examination and survey. The prevalence of periodontal disease and plaque index value were higher in male than female (p < 0.05). The group of 13 years old subjects had the highest prevalence of periodontal disease (73.3%) and plaque index value (p < 0.05). Among the plaque index of each individual tooth, mandibular central incisor showed the highest value. The survey relating anticipated risk factors demonstrated that the group of 13 years old subjects had the least care for oral hygiene. Also, patients who received the treatment of scaling exhibited high plaque index (p < 0.05), and adolescents with great stress loads showed calculus deposition and increased plaque index (p < 0.05).

• Journal of Korean Clinical Health Science
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• v.5 no.4
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• pp.981-990
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• 2017

Purpose: The purpose of the study was to investigate the relationship between job searching efficacy and employment stress of the allied health students. Methods: A self-reported questionnaire was completed by 269 allied health students in Gyeongnam from September to October 30, 2015. The questionnaire consisted of general characteristics of the subjects(5 items), employment stress(22 items), job searching efficacy(27 items). Data were analyzed by SPSS 20. program. Results: In case of the man, good economic level, dissatisfied with major have higher job searching efficacy in allied health students. Department of physical therapy students had higher employment stress. The employment stress has an effect on higher self-esteem, higher employment in information technology, in case of the man, lower career adopted a capability. Conclusions: It is necessary to reduce employment stress of the allied health students. That should be provide support of economical, innovation curriculum development opportunity of self-development on improve the self esteem and employment in information technology, interview skill, writing resume from freshman to broaden understanding of the majors, for the employment stress coping skill.

• Journal of dental hygiene science
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• v.8 no.2
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• pp.65-71
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• 2008

The purpose of this study was to examine people's awareness of health insurance in a bid to help improve the management of dental health insurance coverage. The subjects in this study were 1,036 people who included experts in that field and medical consumers. The findings of the study were as follows: 1. In regard to the demographic characteristics of the expert group including gender and age, the female experts outnumbered the males, as the former accounted for 84.7 percent. And the experts in their 20s made up the largest age group, followed by the 30-39 age group and those in their 40s. As to the demographic characteristics of the medical consumers, the rates of the men and women stood at 49.8 percent and 50.2 percent respectively, which were similar. By age, the largest number of the medical consumers were in their 20s, followed by in their 30s and in their 40s. 2. Concerning opinions on the procurement of finance for health insurance, many respondents in both groups agreed that the health insurance coverage should be enlarged by securing more finance, and that items involved in the coverage should be prioritized again. Regarding a means of securing financial resources, the experts placed the most emphasis on extended budgetary support from the government, followed by establishing a social security system and budget compilation by local governments. The medical consumers attached the most importance to extended budgetary backing from the government, followed by budget compilation by local governments and determining contribution according to income level. 3. As for general view of the dental health insurance, the experts believed that the amounts of copayment and self-payment by the insured were appropriate(2.47), and they found the number of benefitted items to be proper(2.29) as well. The medical consumers thought that the benefit percentage of the dental health insurance in the overall health insurance budget was appropriate(2.26), and they also considered the number of benefitted items adequate(2.16). But this group didn't give a lot of marks to the appropriateness of those things. 4. As to perception about the dental health insurance, both groups took a similar view of it. Specifically, they felt the strong need for a dental health insurance system. In terms of satisfaction level, both groups were dissatisfied with it, and there was a strong tendency for them to be discontented with the health insurance coverage.