• Progress in Medical Physics
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• v.23 no.4
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• pp.252-260
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• 2012

The reduction of radiation dose from x-ray is a main concern in computed tomography (CT) imaging due to the side-effect of the dose on human body. Recently, the various methods for dose reduction have been studied in CT and one of the method is a iterative reconstruction based on total variation (TV) minimization at few-views data. In this paper, we evaluated the image quality between total variation (TV) minimization algorithm and Feldkam-Davis-kress (FDK) algorithm in micro computed tomography (CT). To evaluate the effect of TV minimization algorithm, we produced a cylindrical phantom including contrast media, water, air inserts. We can acquire maximum 400 projection views per rotation of the x-ray tube and detector. 20, 50, 90, 180 projection data were chosen for evaluating the level of image restoration by TV minimization. The phantom and mouse image reconstructed with FDK algorithm at 400 projection data used as a reference image for comparing with TV minimization and FDK algorithm at few-views. Contrast-to-noise ratio (CNR), Universal quality index (UQI) were used as a image evaluation metric. When projection data are not insufficient, our results show that the image quality of reconstructed with TV minimization is similar to reconstructed image with FDK at 400 view. In the cylindrical phantom study, the CNR of TV image was 5.86, FDK image was 5.65 and FDK-reference was 5.98 at 90-views. The CNR of TV image 0.21 higher than FDK image CNR at 90-views. UQI of TV image was 0.99 and FDK image was 0.81 at 90-views. where, the number of projection is 90, the UQI of TV image 0.18 higher than FDK image at 90-views. In the mouse study UQI of TV image was 0.91, FDK was 0.83 at 90-views. the UQI of TV image 0.08 higher than FDK image at 90-views. In cylindrical phantom image and mouse image study, TV minimization algorithm shows the best performance in artifact reduction and preserving edges at few view data. Therefore, TV minimization can potentially be expected to reduce patient dose in clinics.

• The korean journal of orthodontics
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• v.32 no.5 s.94
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• pp.327-342
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• 2002

Soft tissue profile is a critical area of interest in the development of an orthodontic treatment and diagnosis. The purpose of this study was to determine the facial profile preference of diversified group and to investigate the relationship between most Preferred facial Profile and existing soft tissue reference lines. A survey instrument of constructed facial silhouettes was evaluated by 894 lay person. The silhouettes had varied nose, lips, chin and soft tissue subnasale point. Seven sets of facial type were computer-generated by an orthodontist to represent distinct facial types. The varied facial profiles were graded on the basis of most preferred to least preferred. Every facial profile were measured by soft tissue reference lines(Ricketts E-line, Burstone B-line) to observe the most preferred facial profile. The results as follows: 1. In reliability test, the childhood group showed lower value than other groups, which means that this group has no concern on facial profile preference. 2. It appears that sexual and age difference made no significant difference in selecting the profile 3. An agreement to least preferred facial profile was higher than an agreement to most preferred facial profile. 4. Coefficient of concordance (Kendall W) was higher in the twentieth group. It means that a profile preference of the twentieth is distinct. 5. A lip protrusion (to Ricketts E-line and Burstone B-line) of most preferred facial profile was similar to measurements of previous study that investigate skeletal and soft tissue of esthetic facial profile of young Korean. So these reference lines can be used valuably in clinics. 6. Profile of excessive lip protrusion or retrusion to E-line & B-line was least preferred. 7. Most preferred profile of all respondents group was straight profile. Profile that showing convex profile was not pre(erred and the least preferred profile was concave profile.

• Journal of dental hygiene science
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• v.4 no.3
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• pp.117-126
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• 2004

For a month of September, 2004, a questionnaire regarding dental hygiene was distributed to 165 workers of Ulsan area. A total of 125 questionnaire were analyzed: 102 collected of the distributed 165 pieces, and 23 questionnaires reported by patients of a dental clinic in Dong-gu, Woolsan. The result is as follows; (1) Labor workers of Ulsan have thought that they are in good dental health, 44.1% of respondents, following by those who they believe they are in moderate health and those who they think are in poor condition. 89.0% of total workers have experienced dental treatment. (2) Regarding the location of dental treatment, 85.0% of respondents have pointed out dental hospitals and clinics, while 3.9% have indicated that they had treatment from unlicensed dentists. Specifically, workers in their 40s over have ever experienced dental treatment by unlicensed dentists. Those who think they are in poor dental condition have tended to have more dental treatment by unlicensed dentists. (3) Regarding the reason that they put off the treatment, 59.1% of respondents have indicated that they have no time to have the treatment, following by economic burden and the lack of confidence in dentists. When they have tooth aches or the gum ache, 60% of respondents have suggested that they endure the ache or take a medicine to alleviate the pain, showing a lower understanding of early dental treatment. (4) Regarding the reason why they are unwilling to go to dentists, respondents have revealed the anxiety against pain, 50.4%, following by the difficulty of scheduling and unsatisfied services. (5) 47.2% of respondents have brushed their teeth 3 times everyday, following by those who have done it 2 times a day and those one a day. Regarding how to brush the teeth, most of respondents have brushed their teeth in the upper, lower, and the both side, 61.4%. The younger respondents and those who think they are in good dental health have tended to brush their teeth up and down. (6) Regarding the cause of the gum disease, 67.7% of respondents have thought that it is caused by poor dental hygiene, following by natural occurrence due to age, hereditary nature, and physical predisposition. (7) 67.7% of respondents have experienced dental scaling, while 32.3% of them have had no experience in it. 53.5% of workers have thought that scaling may not be recommended since they have the teeth scaled periodically once they had dental scaling, a higher rate than 46.5% who think scaling is good for the gum health.

• Journal of dental hygiene science
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• v.6 no.2
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• pp.133-138
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• 2006

To find out influence of water fluoridation program on the economic benefit effect, this study analyzed comparatively dental treatment indicators obtained from dental clinics at Sangdang-gu in Chenongju City, fluoridated community and Manan-gu in Anyang City, non-fluoridated community, from January 1, 2003 to the end of June, and the results are as follows: 1. If water fluoridation program is carried out in Anyang, non-fluoridated community, the number of treatment from caries and disease of tissues around dental pulp and root apex from age 6 to 18 for the first half of year 2003 is expected to decrease by 1,272, 636 for low estimation, and 1,908 for high estimation. And the treatment cost is expected to decrease by 40,888,000 Wons, 20,444,000 Wons for low estimation, and 61,333,000 Wons for high estimation. 2. Assuming that water fluoridation program is spread to all over the country, the number of treatment per year is expected to decrease by 2,492,018, 1,246,009 for low estimation, and 3,738,027 for high estimation. And the treatment cost is expected to decrease by 80,105,075,000 Wons, 40,052,537,000 Wons for low estimation and 120, 157,612,000 Wons for high estimation respectively. 3. For Yeong-un water supply management office which has 48,925 water supply personnel, the benefit/cost rate was 2.9 times, and for Jibuk water supply management office which has 239,751 water supply personnel, the benefit/cost rate was 9.0 times. As the water supply personnel increased, the cost increase of water fluoridation program was little and as the scale got large, the economic effect was very large. Improving national oral health is thought to be associated with expense retrenchment of oral health insurance financial. So it may need to extend using tap water to all the area of the country and additionally establish confidence through an active public relations and education of water fluoridation program.

• Journal of dental hygiene science
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• v.12 no.5
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• pp.525-534
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• 2012

Study the effect of stress factors and increases in stress at work on the changes in eating behavior and habits and the influence of these changes on the health of dental hygienists. Use the responses of 273 dental hygienists who work in or around the Seoul area after surveying them by post or face to face. The biggest reason for skipping breakfast was having no time (60.4%) and the most desired change in eating habits was over eating (33.0%) while 51.6% responded that they over ate or binge ate due to stress. The largest stress factor was work load 39.6% and subjects responded that after stress the amount of food consumed increased very much for 12.1%, very for 49.8%, indicating increased food consumption than usual. The group with the most job stress had a high level of self stress awareness (p<0.001), nervousness (p<0.01), back pains (p<0.001), optical fatigue (p<0.01), headache (p<0.01) and indigestion (p<0.01). The higher the job stress, the poorer the eating behavior was (p<0.01) and job stress was high for dental hygienists working in dental clinics with less than three dental hygienists (p<0.05). Low eating behavior scores could be seen in groups that took 4 night shifts per week (p<0.05). Job stress scores for high for groups with no break time during work (p<0.001) and these groups showed low eating behavior scores (p<0.01). Furthermore, if high levels of self stress awareness was present, job stress was very high (p<0.001) and eating behavior scores were the lowest (p<0.05). Job stress of dental hygienists impede the eating behavior and habits therefore has a negative influence on their health. There is a need for more efforts to solve this problem and thus maintain the health of dental hygienists.

• Journal of dental hygiene science
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• v.10 no.5
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• pp.403-409
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• 2010

The purpose of this study was to examine the teaching efficiency of clinical training for dental hygiene students in Gyeonggi Province. The subjects in this study were 371 dental hygiene juniors in seven different colleges in Gyeonggi Province, on whom a self-administered survey was conducted. The collected data were analyzed with a SPSS WIN 12.0 program, and the findings of the study were as follows: 1. The teaching efficiency of clinical training that the dental hygiene students undergone was on the average. As for evaluation of the factors of teaching efficiency, they gave the highest marks to the role model factor(3.40). 2. The size of the institutions where they received clinical training made no statistically significant differences to the teaching efficiency of their clinical training. The university hospitals ranked first in professional knowledge, one of the sub-directory of teaching efficiency, and the gap between them and the others was statistically significant(p=.005). 3. Concerning links between satisfaction level with the major and view of teaching efficiency, stronger satisfaction with the major led to better perception of teaching efficiency(p=.001). Among the subdirectory of teaching efficiency, that made statistically significant differences to view of interpersonal skills, performance as a supporter, fair evaluation, academic organization skills(p=.005), encouragement and support, teaching methods, professional academic knowledge(p=.001), communicative competency, performance as a role model and cooperation with the staff of dental clinics(p=.000). 4. There were no statistically significant gaps in teaching efficiency according to teaching styles. Among the sub-directory of teaching efficiency, statistically significant differences were found only in encouragement and support(p=.005). The above-mentioned findings suggest that the teaching efficacy of the clinical training was approximately on the average, and that a better satisfaction with the major led to a higher teaching efficacy. Therefore a wide variety of teaching methods and systematic training programs should be developed to boost the quality of clinical training to improve its teaching efficacy.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.469-474
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• 2009

The purpose of this study was to examine the satisfaction level of parents with elementary school students in some metropolitan areas with the pit and fissure sealing program in a bid to raise awareness of the importance of the preventive treatment and accelerate the spread of it. The subjects in this study were 231 parents who had school children and resided in Seoul and Gyeonggi Province. After a self-administered survey was conducted in October and November 2008, the collected data were analyzed. The findings of the study were as follows; 1. As to places for receiving the preventive treatment, 111 respondents (48.1%) experienced pit and fissure sealing in dental clinics, and 88 respondents(38.1%) did that in dental hospitals. 177 people(76.6%) received that treatment from dentists, and 16 respondents(11.3%) did that from dental hygienists. 2. Concerning whether to be for or against the pit and fissure sealing program, more than half that numbered 143(61.9%) supported that program, and 88 respondents(38.1%) didn't. As for satisfaction level, they expressed the biggest satisfaction with the preventive effect of that treatment($3.92{\pm}.85$), and were least satisfied with the cost($1.91{\pm}.86$). 3. Regarding links between general characteristics and satisfaction level, they were statistically significantly different in satisfaction level with the cost according to residential area and the number of child, and age made a statistically significant difference to their satisfaction level with the preventive effect of it. 4. As for relationship between warranty term and whether to be for the pit and fissure sealing program or not, 45(31.5%) out of those who supported the program were provided with no warranty, and 32(36.4%) out of those who took a stand against it were provided with no warranty, either. Warranty was provided to 12(8.4%) respondents of the former group without a fixed term, but that's not the case for any of the latter. The warranty term made statistically significant differences to their agreement or disagreement to the program(p<0.05).

• Journal of dental hygiene science
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• v.14 no.3
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• pp.311-318
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• 2014

The purpose of this study was to look into the perception, experience, treatment of early childhood caries (ECC) and influential factors of perception in order to provide basic data useful for preventing the ECC by examining the relationship between oral health of young children in infancy and mother. In this study, 277 mothers were surveyed who had children in children under 6 years old and visiting the pediatrics, day care center, and pediatric dental clinics located in Daegu and Gyeongsangbuk-do from July 10, 2013 to September 5 of the same year. The results obtained from the survey were analyzed through chi-square test, t-test, and binary logistic regression analysis by using the SPSS 18.0, a statistical program. The results of analysis showed that ECC in children under 6 years old was associated with mother's age, education background of mothers, number of children and monthly income and had a significant correlation with mother's oral health-related knowledge and oral health care of their children. Thus, it would be necessary to develop oral health education programs and implement such oral health education programs at a national level on a regular basis for the mothers of young children in infancy and would-be mothers in order to reduce the ECC in infancy and promote oral health.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.26-45
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• 1992

This study presents the behavioral and cognitive changes by administration of methylphenidate(MPH) and imipramine(IMI) for the treatment of attention-deficit hyperactivity disorder(ADHD) in $5_{1/2}{\sim}12$ years old children referred to child psychiatric clinics. Behavioral changes are assessed with parent's and teacher's ratings. Drug effects on attention. short-term memory, and impulsivity are evaluated with psychological tests in laboratory. The changes were assessed twice in a 8-week periods. The data were analyzed seperately for 15 subjects each drug using repeated measured analysis of variance(ANOVA). The findings indicates that behavioral and cognitive impairments are improved by both drugs, but impulsivity is not. And MPH is superior to IMI on the improvement of attentional problem ; especially the findings indicates important differences between simple task and complex. perceptual-search task. These data confirm the effectiveness of MPH for treatment of ADHD, also raise questions regarding assessment method of attention and impulsivity as fell as importance of impulsivity in ADHD.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.26 no.3
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• pp.197-208
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• 2015

Objectives : The purposes of this study were to examine the reliability and validity of the Korean version of Social Communication Questionnaire (K-SCQ) and to determine cut-off scores for diagnosis of autism spectrum disorder (ASD). Methods : A total of 166 subjects with ASD and their 186 unaffected siblings were recruited through child psychiatry clinics of university hospitals. Board certified child psychiatrists screened all probands suspected to have ASD based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. To confirm the diagnoses, the Korean versions of the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview-Revised (K-ADI-R) were administered to all the subjects. All parents completed the K-SCQ and Social Responsiveness Scale (SRS). The non-ASD siblings were evaluated with the same instruments as the probands with ASD. We performed a factor analysis to examine the structure of K-SCQ. For testing the validity of K-SCQ, we compared the difference in Lifetime and Current scores of probands with ASD and their non-ASD siblings using t-test and analysis of covariance. Correlations between the K-SCQ and other measurements of ASD symptomatology, including K-ADI-R totals and domain scores and SRS, were examined. Receiver operation characteristic curve analysis was performed to extract cutoff scores discriminating affection status. Results : Four factors were extracted through factor analysis of K-SCQ ; 1) social relation and play, 2) stereotyped behavior, 3) social behavior, and 4) abnormal language. Cronbach's internal consistency was .95 in K-SCQ Lifetime, and .93 in K-SCQ Current. There were significant differences in total score of K-SCQ, both in Lifetime and Current between the ASD group and non-ASD siblings group (p<.05). K-SCQ scores were significantly correlated with K-ADI-R subdomain scores and SRS total scores (p<.05). The best-estimate cut-off scores of K-SCQ for diagnosis of ASD were 12 for 48 months and over, and 10 for below 47 months. Conclusion : Our findings suggest that the K-SCQ is a reliable and valid instrument for screening autistic symptoms in the Korean population. Lower cut-off scores than the original English version might be considered when using it as a screening instrument of ASD.