• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.3
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• pp.347-359
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• 2023

Objective: This study aimed to evaluate the suitability of polydeoxyribonucleotides (PDRN) as a storage medium for avulsed teeth. Materials and Methods: The viability of human periodontal ligament (PDL) cells stored in Hank's balanced salt solution and PDRN solutions (concentrations, 10, 25, 50, and 100 ㎍/mL) and tap water was measured using the Cell Counting Kit-8 and Live/Dead assays. In addition, Nitric oxide detection and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to evaluate the anti-inflammatory effect of PDRN. Results: The viability of PDL cells stored in a 100 ㎍/mL PDRN solution was significantly higher than that of cells stored in the other solutions (p < 0.01). Furthermore, cells stored in 100 ㎍/mL PDRN solution demonstrated a significantly reduced NO production (p < 0.0001), and cells stored in 50 and 100 ㎍/mL PDRN solutions expressed significantly lower levels of tumor necrosis factor α, interleukin (IL) -4, IL-6, and IL-10 (p < 0.01) compared to cells stored in HBSS. Conclusion: The PDRN solution exhibited cell-preserving and anti-inflammatory effects on the PDL cells. The findings of this study can serve as a basis for further experiments directed at the development of an effective storage medium for avulsed teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.379-385
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• 2023

With the recent development of digital dentistry, fully digitalized methods for fabricating dentures, using intraoral scans and computer-aided design/computer-aided manufacturing (CAD-CAM), are getting popular. Digital methods have the advantage of simplifying the fabrication process in the clinic and laboratory, supplementing digital data. This case report shows a fully digital fabrication method for interim removable dentures in a patient with anterior tooth loss in which implant placement is impossible or delayed. Interim removable dentures were fabricated using two methods. One method is printing tooth and base parts separately and combining, and the other method is printing the whole denture at one time and coloring on the base part. Afterward, dentures were delivered and adaptation was evaluated using the triple scan technique. The extracted site was scanned intraorally (first scan) and the interim removable denture was digitally scanned both intraorally (second scan) and, after removal extraorally (Third scan). In both method, denture adaptation was shown favorable. We report this case report as both the patient and the operator were satisfied with a simplified process using a fully digital method in the clinic.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.369-373
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• 2001

The congenital missing of mandibular second premolars is among the common dental anomaly in children. When a second premolar is diagnosed as congenitally missed, we should consider many factors influencing the treatment plan such as patient's age, states of roots of 2nd primary molar, degree of crowding, skeletal growth pattern, facial profile, procumbency of the incisor and lower facial height, etc. The mineralization of the second premolars begins in the majority of cases at the age of $2\sim2\frac{1}{2}$ years, but this period varies more widely than those for other permanent teeth. Also, mandibular second premolars show the greatest variations in differentiation and calcification. For this reason, aplasia of this group of teeth cannot be diagnosed at early age and with the same degree of certainty. From the clinical studies with 2 cases and some literature review on late development of second premolars, it could be summarized as follows : 1. The 2 cases showed marked delay in the development of mandibular second premolars. 2. After the crypt formation, the speed of calcification seemed nearly normal, suggesting that the delay was due to differentiation rather than calcification. 3. When one is encountered with similar conditions, it would be desirable to consider the possibility of delayed tooth development.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.91-108
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• 2000

Most of cervical abrasion and erosion lesions show gingival margin where the cavosurface angle is on cementum or dentin. Composite resin restoration of cervical lesion shrink toward enamel margin due to polymerization contraction. This shrinkage has clinical problem such as microleakage and secondary caries. Several methods to diminish contraction stress of composite resin restoration, such as modifying cavity form and building up restorations in several increments have been attempted. The purpose of this study was to compare polymerization contraction stress of composite resin in Class V cavity subjected to cavity forms and placement methods. In this study, finite element model of 5 types of Class V cavity was developed on computer tomogram of maxillary central incisor. The types are : 1) Box cavity 2) Box cavity with incisal bevel 3) V shape cavity 4) V shape cavity with incisal bevel 5) Saucer shape cavity. The placement methods are 1) Incisal first oblique incremental curing 2) Bulk curing. An FEM based program for light activated polymerization is not available. For simulation of curing dynamics, time dependent transient thermal conduction analysis was conducted on each cavity and each placement method. For simulation of polymerization shrinkage, thermal stress analysis was performed with each cavity and each placement method. The time-temperature dependent volume shrinkage rate, elastic modulus, and Poisson's ratio were determined in thermal conduction data. The results were as follows : 1. With all five Class V cavifies, the highest Von Mises stress at the composite-tooth interface occurred at gingival margin. 2. With box cavity, V shape cavity and saucer cavity, Von Mises stress at gingival margin of V shape cavity was lower than the others. And that of box cavity was lower than that of saucer cavity. 3. Preparing bevel at incisal cavosurface margin decreased the rate of stress development in early polymerization stage. 4. Preparing bevel at incisal cavosurface margin of V shape cavity increased the Von Mises stress at gingival margin, but decreased at incisal margin. 5. At incisal margin, stress development by bulk curing method was rapid at early stage. Stress development by first increment of incremental curing method was also rapid but lower than that by bulk curing method, however after second increment curing final stress was the same for two placement methods. 6. At gingival margin, stress development by incremental curing method was suddenly rapid at early stage of second increment curing, but final stress was the same for two placement methods.

• Journal of Korean society of Dental Hygiene
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• v.11 no.2
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• pp.197-211
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• 2011

Objectives : OHIP-14 and EQ-5D were used, targeting the residents of farming communities to identify the elements that influence oral cavity's health and quality of life due to health and to identify the importance of oral cavity's health in order to increase health of adults' oral cavity and quality of life via improved health. Methods : This research was conducted from July 17th, 2010 to August 16th, 2010 targeting 600 residents in Goryeong-gun, Gyeongsangbuk-do, aging over 40. The data has been analyzed using Mann-Whitney U test, Kruskal-Wallis test and hierarchical multiple regression through SPSS Win Program 18.0 version. Results : 1. OHIP-14 and EQ-5D based on general characteristics showed lower oral health-related quality of life and health-related quality of life on the following cases: women (p=0.004, p<0.001), older (p<0.001, p<0.001), lower scholastic ability (p<0.001, p<0.001), lower average of average spending money (p<0.001, p<0.001), higher number of chronic disease (p<0.001, p<0.001), less drinking (p=0.012, p=0.008), lower perceived oral health and health status (p<0.001, p<0.001) and non smoking showed only EQ-5D (p<0.001). 2. OHIP-14 and EQ-5D based on oral health behavior showed lower oral health-related quality of life and health-related quality of life on the following cases: no periodic oral check-up (p<0.001, p<0.001), less experience of oral health education (p<0.001, p<0.001), horizontal tooth-brushing method(p<0.001, p<0.001) and lower frequency of tooth-brushing showed only OHIP-14 (p=0.042). OHIP-14 and EQ-5D based on oral health status and subjective oral symptom showed lower oral health-related quality of life and health-related quality of life on following cases: number of existing tooth less than 20 (p<0.001, p<0.001), the number of missing teeth more than 9 (p<0.001, p=0.044), DMFT (Decay, Missing, Filling Teeth) index more than 18 (p<0.001, p<0.001), wears denture (p<0.001, p<0.001), edentulous (p<0.001, p=0.002), have xerostomia (p<0.001, p<0.001) and have chewing discomfort (p<0.001, p<0.001). 3. Factors affecting OHIP-14 were gender, age, perceived oral health status, perceived health status, number of existing teeth, dental status, xerostomia and chewing discomfort, and the of reliability (how well it explains) the final model was 48.7%. EQ-5D showed relevance on gender, age, presence of chronic disease, perceived health status, xerostomia, chewing discomfort and oral health-related quality of life, and the reliability of the final model was 42.9%. Conclusions : In order to improve the quality of life of ruralists, oral health needs to be improved or remained by increasing the rate of possession of the existing teeth and preventing the loss of teeth. In order to do so, improvement of accessibility of dental clinic, change of direction from treatment-centered to prevention-centered health care system, development of oral health education program and various oral health care policies which would vitalize continuous oral health care system are considered to be necessary.

• Journal of Preventive Medicine and Public Health
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• v.5 no.1
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• pp.97-104
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• 1972

For the purpose of ascertaining the status of physical growth and health status of the University Students, an intensive survey was conducted by the authors towards a total of 1,250 (Male 792, Female 458) who passed the written entrance examination at the Kyung Hee University in 1972. The items included the measurements on physical growth, various physical and nutritional indices, status of visual distourbance, dental status and tuberculosis. The findings and results cad be summarized as follows; 1. Physical Growth and Develspment. i) The average of body height by anthropometric was $169.39{\pm}5.05cm$ in male and $157.45{\pm}4.43cm$ in female. ii) The averages of body weight by sex were $59.42{\pm}6.47Kg\;and\;51.81{\pm}5.21Kg$, respectively. iii) The averages of chest-girth were $87.18{\pm}5.30cm\;and\;80.51{\pm}4.53cm$. iv) The averages of sitting-height were $92.21{\pm}2.79cm\;and\;86.28{\pm}2.57cm$. In all cases the male measurements were higher than female. 2. Various ludices about Physical Growth and Development; i) Relative body weights by sex were 35.08 and 32.91, relative chestgirth 51.47 and 51.13, and relative sitting-height 54.43, 54.79, respectively. ii) Rohrer index was 1.222 in males and 1.327 in females, Kaup index 2.071 and 2.089, Verveck index 86.54 and 84.04, and Pelidisi index 91.15 and 93.08, respectively 3. Status of visual distourbance The vision of the students under 0.8 with Landolt's testing chart was 45.4% in left eye and 46.6% in right eye(male: 44.4% and 45.7%, female: 47.2% and 48.0%), while under 0.6 in both visions was 41.0% and 40.5% (male: 40.8% and 40.7%, female: 41.5% and 40.2%), respectively. 4. Dental Status Out of total 19.4% (male 19.2%, female 19.6%) had gingivitis, the female incidence rate of gingivitis was higher than male. Average number of teeth in each subject was 29.6 teeth: male had 29.9 teeth and female had 29.1 teeth. The caries rate was 78.9%(male 75.6%, female 84.5%), the female caries rate was higher than male. Total filing per subject was 35.6% (male 34.0%, female 37.1%), female incidence was higher shan male. The average number of i) Caries per tooth rate was 8.5% in male and 9.2% in female, ii) Missing per tooth rate was 0.3% and 0.2%, iii) Filling per tooth rate was 3.9% and 4.2%. in all cases, the female incidences were higher than the male. The average number of D.M.F. was 3.8 teeth in male and 4.0 teeth in female, female was higher than male. The average rate of D.M.F. was 12.7% in male and 13.7% in female, female was higher than male. 5. Pulmonary infiltration Among the total, 53 students were diagnosed as pulmonary infiltration (tuberculosis), of whom 51 were minimal cases, one were moderately advanced case and one were far advanced case.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.272-279
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• 2015

This study was conducted to provide baseline data which could suggest a direction of role based efficient integrated clinical education by avoiding duplicate of contents through analyzing clinical courses. Among the 7 clinical courses, orthodontics and periodontology were the most published subjects which were published in 5 kinds of books and dental materials was the least published subject which was published in 2 kinds of books on investigation of overlapping contents based on titles that appeared on chapters and verses of all textbooks for clinical courses. Dental implant was covered in 4 subjects such as oral maxillofacial surgery, prosthodontics, periodontology and dental materials which was the most number. Other overlapping contents were restoration treatment, occlusion and malocclusion, temporomandibular joint diseases, anesthesia sedation, tooth trauma, systemic disease and dental treatment, dental casting, isolation techniques, tooth bleaching, pulp protection, gingivitis periodontitis, tooth development, etc. Reviews of textbooks of clinical courses should be conducted in a detailed manner by systematic, various studies in order to improve quality of the textbooks.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.237-243
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• 2011

The purpose of study is for the certified correlations of hand-wrist radiograph with cervical vertebrae for skeletal maturation in children. Normal evaluation devices of growth stage is sexual feature, biological age, tooth development stage, height and weight. Evaluation of growth potential is very important for childhood and puberty. The skeletal developmental stages were evaluated by using the hand-wrist radiograph and cephalometric radiograph that obtained from 6 to 18 years old children. 1. Chronologic age was not more suitable indicator of skeletal development compared to Skeletal Maturity Indicators(SMI) and Cervical Vertebrae Maturation(CVM) stages. 2. SMI and CVM stages for females occurred earlier than that for male. 3. SMI 1 and 2 stages were corresponded to CVM 1; SMI 3,4 = CVM 2; SMI 5,6 = CVM 3. 4. Reproducibility and reliability of observer for SMI and CVM were excellent. This results suggest CVM stage is comparable to SMI stage in terms of evaluating the skeletal development.

• Journal of Technologic Dentistry
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• v.34 no.3
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• pp.303-314
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• 2012

Purpose: This study aimed to find overseas workplace and improve global competence through the preference survey on overseas employment by dental technology students. Methods: The survey sample consisted of 250 randomly selected dental technology students. Survey was conducted from March 1 to May 1 in 2012. Total of 245(98.0%) replies and analyzed 236 questionnaires excluding 9 incomplete questionnaires. The questionnaires used in this study consisted of 7 items for general information, overseas employment characteristics of 10 items, 7 items for overseas employment activation plane and job competency development of 7 items. Collected data were analyzed using SPSS(Statistical Package for Social Sciences) Win 19.0 statistics program. Results: Regarding general characteristics of the subjects, there were 131 third graders(55.5%), 63 first graders(26.7%) and 42 second graders(17.8%) among 130 males(55.1%) and 106 females(44.9%). 221(93.6%) of the subjects had no experience in language training. Students who had clinical training for 1-5 months were 123(52.1%), and 24(10.2%) students had more than six months. 89(37.7%) of the subjects had no clinical training. 155(65.7%) of the subjects hope to work with korean owner, and 81(34.3%) chose foreign owner. Favored working countries were Australia(41.5%), the United States(29.2%), Canada(18.2%) and other(11.0%). The field of dental ceramic was indicated to be the highest proportion of 104(44.1%). Period of training were 3 hours(40.3%) and 6 hours(35.2%). The most important training were language-centered education(54.2%), Job-oriented education(24.2%), local culture education(16.1%), other(3.0%) and Leadership Training(2.5%). The subjects chose overseas worker(44.9%), working-level practitioner (28.8%), successfully employed dental technology graduate(19.5%a) and professor(3.4%) as an instructor. The subjects get education and training information from professor(40.3%), other(28.0%), senior(14.4%), job site(8.9%) and acquaintance(8.5%). A credit exchange(2.46 points), a joint degree program(2.46 points), and a foreign professor(2.33 points) were needed to activate the overseas employment. A kind of dental prosthesis(3.58 points), carving tooth morphology(3.38 points), and majors of dental technology(3.30 points) were indicated to develop job competency for overseas employment. Age, year, clinical training experience and company owner were statistically meaningful data among the general characteristics affecting job competency development. Conclusion: The college needs to offer variety programs such as foreign language-centered education and a local job competency development program to graduates to be connected with international workplace and employment.

• Journal of Korean society of Dental Hygiene
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• v.11 no.6
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• pp.1017-1025
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• 2011

Objectives : Periodontal disease is a serious oral disease that frequently occurs among adults. The objective of this study is to provide necessary data for the development of an oral health care program that can effectively manage periodontal disease and subsequently maintain and enhance oral health. Methods : Data was collected from patients of a dental clinic in Daejeon, Korea from 1 July to 25 August 2009. A thesis submitted to the Committee of Graduate School of Public Health & Biotechnology Chungnam National University in partial fulfillment of the requirements for the degree of Master of Public Health conferred in February, 2010. Results : 68% of the patients were aware of periodontal disease, with older patients exhibiting better awareness. 48.0% replied that their periodontal health is good in general, with older patients inclined to say that their periodontal health was poor. 70.5% cited bad brushing habit or skipping the act of tooth brushing as the cause of periodontal disease, while 63.5% reported brushing their teeth an average of 3 times a day. 56.5% said that they brush their teeth correctly, and 63.5% told that they brush their teeth up and down, and left to right and 70.0% replied that they would attend an educational program for the prevention of periodontal disease, with older patients shown to more likely attend such a program. Conclusion : a program that can motivate people to become aware of the importance of oral health care should be developed and implemented. Such a program should include the dissemination of correct and accurate oral health care information and measures for educating people about the importance of prevention.