• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.407-414
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• 2003

The aim of this study was to investigate the effect of third molar extraction on the periodontal status of the adjacent second molar. A total of 61 second molars in 31 adult periodontitis patients were examined. Among them, 27 second molars without adjacent third molars were included in the test group, and 34 second molars with third molar were included in the control group. Clinical parameters including plaque index, gingival index, and pocket depth and radiographic bone loss were measured around the second molar both in test and control group. The result showed that: (1) the mean plaque index and gingival index of control group were higher than these of the test group but the difference was not statistically significant, (2) the mean pocket depth of the control group was higher than the test group significantly at distal and buccal surface, (3) radiographic hone loss was greater in control group than test group significantly, (4) in Pearson correlation analysis between the age of extraction and radiographic bone loss in the test group, a positive relationship was shown(p<0.01). Within limitation of this study, it may be concluded that third molar extraction in periodontitis patients showed an improvement in periodontal status in contrast the patients group having third molar, therefore earlier a removal of third molar may minimize radiographic hone loss of the adjacent second molar.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.6
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• pp.371-381
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• 2022

Objectives: This study determined the effect of platelet-rich fibrin (PRF) on extraction socket bone regeneration and assessed the patterns and determinants of bone regeneration after the surgical extraction of impacted mandibular third molars. Materials and Methods: This prospective study randomly allocated 90 patients into two treatment groups: A PRF group (intervention group) and a non-PRF group (control group). After surgical extractions, the PRF group had PRF placed in the extraction socket and the socket was sutured, while the socket was only sutured in the non-PRF group. At postoperative weeks 1, 4, 8, and 12, periapical radiographs were obtained and HLImage software was used to determine the region of newly formed bone (RNFB) and the pattern of bone formation. The determinants of bone regeneration were assessed. Statistical significance was set at P<0.05. Results: The percentage RNFB (RNFB%) was not significantly higher in the PRF group when compared with the non-PRF group at postoperative weeks 1, 4, 8, and 12 (P=0.188, 0.155, 0.132, and 0.219, respectively). Within the non-PRF group, the middle third consistently exhibited the highest bone formation while the least amount of bone formation was consistently observed in the cervical third. In the PRF group, the middle third had the highest bone formation, while bone formation at the apical third was smaller compared to the cervical third at the 8th week with this difference widening at the 12th week. The sex of the patient, type of impaction, and duration of surgery was significantly associated with percentage bone formation (P=0.041, 0.043, and 0.018, respectively). Conclusion: Placement of PRF in extraction sockets increased socket bone regeneration. However, this finding was not statistically significant. The patient's sex, type of impaction, and duration of surgery significantly influenced the percentage of bone formation.

• Journal of Nutrition and Health
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• v.24 no.5
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• pp.458-468
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• 1991

The purpose of the study was to find out the eating behavioral difference and various connected factors between boys and girls of middle school students. One hundred ninety boys and two hundred six girls. who were sampled from the third graders of middle school located in Seoul and Chungbuk were asked to lilt out the questionaires. The results are summerized as follows : The boys had a better morning appetite and lower rate of skipping breakfast than the girls had. The girls carried more home-prepared boxed lunches and kept the lunch time better than the boys did. On weekend lunch time became more irregular and students had snacks more often than on weekdays. The number of lunchbox sidedishes was significantly influenced by the family composition, number of siblings, schooling of parents, occupation of tile father, and mother's empolymemt status. The frequency of snacks was significantly influenced by schooling of parents.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.46-52
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• 2002

Purpose : We examined the relationships between the root curvatures of the mandibular third molars and their locations on the mandible, so that it might be contributed to elucidate the origin of the formation and development of the Korean mandibular third molar and help many clinicians to treat the mandibular third molars. Materials and Methods : Panoramic radiographs of 237 patients who had been treated at Korea University Ansan Hospital from March, 2000 to April, 2001 and had bilateral mandibular third molars were examined and analyzed. Results : There was no statistically significant difference between men and women (p<0.05). But there were significantly fewer subjects with bilateral curved roots in bilateral third molars regardless of their status (p<0.01) and were statistically significant differences between the groups with bilateral curved roots in the mandibular third molars with same status and with unilateral curved roots in the mandibular third molars with different status and between the groups with unilateral curved roots in the mandibular third molars with same status and with bilateral curved roots in the mandibular third molars with different status(p<0.05). Subjects with bilateral curved roots in the mandibular third molars with bilateral partial impacted status and with bilateral curved roots in the mandibular third molars with bilateral complete eruption status were significantly fewer (p<0.01) and subjects with the mandibular third molars with partial impacted and complete impacted status and with the mandibular third molars with complete erupted and partial impacted status had significantly fewer bilateral curved roots (p<0.05). Conclusions : When we postulate that it is genetic and environmental factors that affect the root formation, it seems that environmental factors have more effects on the formation of the mandibular third molars than on that of the mandibular first and second molars

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.175-180
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• 1996

In this paper, a new image segmentation method based on merging of two low contrast neighbor regions iteratively is proposed. It is suitable for very low bit rate coding. The proposed method reduces efficiently contour information and preserves subjective and objective image quality. It consists of image segmentation using 4-level hierarchical structure based on mathematical morphology and 1-level region merging structure using the contrast difference of two adjacent neighbor regions. For each segmented region of the third level, two adjacent neighbor regions having low contrast difference value in fourth level based on contrast difference value is merged iteratively. It preserves image quality and shows the noticeable reduction of the contour information, so that it can improve the bottleneck problem of segmentation-based coding at very low bit rate.

• Culinary science and hospitality research
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• v.10 no.3
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• pp.18-31
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• 2004

Korean food industry has been developed while it receives footlights as the most encouraging industry and composing one axis of food industry under various marketing activities and severe competitions. The purpose of this study was to understand customer's reason to use bakery, extract important factor, systematically analyze and suggest the direction of bakery industry through study on the character of bakery-user. The researcher Modified the Questionnaire developed by Yoon, YH(2000) & Kim, SE(2002). The major findings obtained from this study were as follows. First, on factors of confidence and propriety, price and communication with consumers, product and service, and service response, there was a high difference between male and female. Second, on factors of accessibility & product and service, there was a high difference among disparity of age. Third, on item of confidence and propriety, there was a high difference among customers' residing styles. Fourth, in relation to income level, there was statistically no difference.

• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.295-303
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• 2007

In this paper we investigate the boundedness character of the positive solutions of the rational difference equation of the form $$x_{n+1}=\frac{a_0+{{\sum}^k_{j=1}}a_jx_{n-j+1}}{b_0+{{\sum}^k_{j=1}}b_jx_{n-j+1}},\;\;n=0,\;1,...$$ where $k{\in}N,\;and\;a_j,b_j,\;j=0,\;1,...,\;k $, are nonnegative numbers such that $b_0+{{\sum}^k_{j=1}}b_jx_{n-j+1}>0$ for every $n{\in}N{\cup}\{0\}$. In passing we confirm several conjectures recently posed in the paper: E. Camouzis, G. Ladas and E. P. Quinn, On third order rational difference equations(part 6), J. Differ. Equations Appl. 11(8)(2005), 759-777.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.2
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• pp.185-195
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• 1999

The purpose of this study is to identify store image and clothing satisfaction of various clothing distribution type and is to compare the difference due to demographic variables. The data were obtained 407 housewives using questionnaire. The results were as follows. First Store image of clothing distribution types was found significant differences in product service atmosphere. Second Clothing satisfaction of clothing distribution types was founded significant differences in price brand name fashion design material sewing size. Third The new distribution types in general were not visited upon despite their high degree of recognition and using experience of new distribution types was founded significant differences in Store image of new distribution types. Fourth Among demographic variables significant difference in usage of the distributions was founded. Fifth Among demographic variables significant difference in usage of the distributions was founded. Fifth Among demographic variables significant difference in clothing satisfaction of the distributions was founded.

• East Asian mathematical journal
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• v.37 no.4
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• pp.381-400
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• 2021

In this study, we compare the multiple intelligence of gifted students with the multiple intelligence of their children recognized by their parents. The subjects of the study are 118 students and their parents at the gifted education center affiliated with A University. First of all, there is a difference between the multiple intelligence of gifted students and the multiple intelligence recognized by their parents. Parents are highly regarded their children in all multiple intelligence components. Second, there are differences in multiple intelligence of gifted students' gender. The difference in multiple intelligence of children recognized by parents depending on the gender of the student was similar to the student's results. Third, there are not much difference in multiple intelligence between elementary and middle school students. However, there is a big difference between students and parents in the elementary school group compared to the middle school students. Therefore, since multi-intelligence can be developed by individual experience and environment throughout one's life, an educational environment that reflects objective evaluation and student needs rather than parental subjective judgment should be created.

• The Journal of the Korean dental association
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• v.56 no.1
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• pp.42-48
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• 2018

INTRODUCTION The most commonly impacted tooth is the third molar. An impacted third molar can ultimately cause acute pain, infection, tumors, cysts, caries, periodontal disease, and loss of adjacent teeth. Local anesthesia is employed for removing the third molar. This study aimed to evaluate the efficacy and safety of 2% lidocaine with 1:80,000 or 1:200,000 epinephrine for surgical extraction of bilateral impacted mandibular third molars. METHODS Sixty-five healthy participants underwent surgical extraction of bilateral impacted mandibular third molars in two separate visits while under local anesthesia with 2% lidocaine with different epinephrine concentration (1:80,000 or 1:200,000) in a double-blind, randomized, crossover trial. Visual analogue scale pain scores obtained immediately after surgical extraction were primarily evaluated for the two groups receiving different epinephrine concentrations. Visual analogue scale pain scores obtained 2, 4, and 6 h after administering an anesthetic, onset and duration of analgesia, onset of pain, intraoperative bleeding, operator's and participant's overall satisfaction, drug dosage, and hemodynamic parameters were evaluated for the two groups. RESULTS There were no statistically significant differences between the two groups in any measurements except hemodynamic factors (P > .05). Changes in systolic blood pressure and heart rate following anesthetic administration were significantly greater in the group receiving 1:80,000 epinephrine than in that receiving 1:200,000 epinephrine ($P{\leq}01$). CONCLUSION The difference in epinephrine concentration between 1:80,000 and 1:200,000 in 2% lidocaine liquid does not affect the medical efficacy of the anesthetic. Furthermore, 2% lidocaine with 1:200,000 epinephrine has better safety with regard to hemodynamic parameters than 2% lidocaine with 1:80,000 epinephrine. Therefore, we suggest using 2% lidocaine with 1:200,000 epinephrine rather than 2% lidocaine with 1:80,000 epinephrine for surgical extraction of impacted mandibular third molars in hemodynamically unstable patients.