• Journal of Korean Dental Science
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• v.3 no.1
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• pp.17-24
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• 2010

Objective : To investigate the prevalence of dental anomalies and to determine the associations between dental anomalies in permanent teeth Materials and methods : The samples were 1,240 patients (760 females and 480 males, mean age=15.1 years) who visited the Samsung Medical Center. Dental anomalies were diagnosed using pre-treatment dental casts, radiographs, clinical examinations, and medical/dental histories. Prevalence and association were investigated according to gender and sidedness. The Chi-square test was performed for statistical analysis. Results : The most common missing tooth was the lower lateral incisor, followed by the lower and upper second premolars. This particular dental anomaly is characteristic of the East Asian population (prevalence of congenital missing tooth=12.3%). The upper anterior area was the most frequently affected area (prevalence of supernumerary tooth was 1.5%). The presence of a supernumerary tooth was more prevalent in males than in females (p<.05, odds ratio=3.2). The most frequently affected tooth was the upper canine (prevalence of impacted tooth=4.3%). Unilateral impaction of the upper canine occurred significantly more often compared to bilateral impaction (p<.001). The prevalence of peg lateralis was 2.7%. The presence of congenital missing tooth was closely associated with peg lateralis (p<.01). If children aged 7~8 years have peg lateralis, the rest of the teeth should be checked for congenital absences. Conclusion : The early detection of dental anomalies and understanding of their associations help clinicians determine the appropriate treatment timing and methods of dealing with these anomalies.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.299-307
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• 2018

This study survey research of infection control, wastewater management, and instrument disinfection according to characteristic at Daegu, Gyeongbuk Province In 2012 and 2017, the same 114 dental clinics to identify the infection management behavior and prevent infection of dental medical institutions. Scored mean 3.37 points on 8 items of infection control, 95.5% in "records of the patient's medical history", 1.8% in "presence of a wastewater facility." Scored 94.7% in "disinfection of metal trays", 17.5% in "storage from a spitting receptacle in the waste bin and commissioned management.", Scored higher in of infection control, wastewater management and instrument disinfection according to general characteristics and dental characteristics in 2017 than in 2012. Points were higher dental hygienist, University graduation, Type of duty was counseling and management, hospital or higher, Number of dentist(dental hygienist, chair, patient) was high. Therefore raise a need for infection control into consideration the dental characteristics and education and promotion regardless of the hospital size.

• Journal of Korean Dental Hygiene Science
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• v.3 no.1
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• pp.15-24
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• 2020

Background: The program aims to enable the participants to receive oral health care with sustainability and give them the choice and prior autonomy of dental practitioners while enhancing the benefits of sustainability. The purpose of this study is to investigate the necessity, awareness, and satisfaction of the implementation of the registered dentist program for children and adolescents, and to promote the introduction of RDPCA. Methods: The survey targeted adult residents in their 20s or older who live in Seoul, an area that continuously implements the RDPCA system, especially in the cities of Cheonan and Asan Results: 79.7% were the most unaware. However, RDPCA participants were significantly more aware than non-participants. When surveying the desire to participate in RDPCA, 96.6% of the respondents said they would 'participate' in the non-RDPCA participate group. The analysis of the satisfaction level of the RDPCA received by their children indicated that 48.6% expressed their satisfaction, and 47.3% said they were healthy. There was a high percentage of people who said they would recommend RDPCA to others as well as a high rate of those who said they would continue to use RDPCA. Conclusions: The reality is that the awareness and implementation of RDPCA are low. For the development of oral health care programs for all children and adolescents in Korea, and the improvement of the satisfaction level of the dental care system, there should be an active consideration of high-quality programs and.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.359-367
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• 2016

This study will be used as basic data to hold clinical training effective by researching and analyzing frequency, satisfaction and stress for the clinical practice of dental hygiene course students. The survey was undergone from Feb. 1, 2014 to Mar. 31 for 219 dental hygiene course juniors who had experienced clinical training in 3 year colleges located in Daejeon and Chungcheong Province. From the study, general and university hospital holds the highest satisfaction in clinical practice and dental offices in acquiring skills. Also, a significant difference is shown between the frequency and satisfaction according to clinical training sheets. The highest degree of stress is shown in dental offices for 'toothbrushing training and dental health education' and in general and university hospital for 'patient counselling'. Therefore, consideration should be made to establish the direction of education, standard criteria and evaluation method for student clinical training to raise its effectiveness.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.80-88
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• 2011

The dental high-speed air turbine handpiece is one of the most popular devices that have been widely used as the main means of cutting tooth structure and restorative material in dentistry. In consideration of usage and marketability of the dental handpiece, it is obviously worthy of investigating it. The goal of this paper is to establish the relationship between the air turbine speed and the supply route inside the handpiece. To do this, the Computational Fluid Dynamics(CFD) tool, Fine$^{TM}$/Turbo is used and the optimal supply route position is suggested from the simulation results. In addition, as an attempt for domestic product, the reverse engineering process of a high speed dental handpiece by 3D X-Ray CT equipment and wire cutting is presented for the Mark II model in NSK. In doing so, the 3D modeling of the handpiece parts is carried out with CATIA V5, and the interference between parts is examined. Finally, the result of performance test for the prototype produced in this research is presented.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.131-139
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• 2008

It's very important to find the most appropriate adhesion technique available, taking into consideration factors such as biocompatibility, non-corrosiveness, mechanical stability, etc. Laser welding is the best choice you can make because from a mechanical viewpoint, a laser welded surface has better particle structure than does a casted particle structure. Furthermore, it requires no additional material and the same metal alloy which is used when casting can be used. Therefore, the resulting mixture will consist of a single alloy, instead of utilizing different alloy combinations. Another benefit is the low economic cost. The most beneficial aspects of laser welding is that it is biologicallly friendlly, doesn't require soldering, can fuse different metal alloys together, and can weld on heat-sensitive spots(E.g. around resin or ceramic). A consistent strong pulse is possible. This technique is capable of welding on master models and creates accurate welds. It is capable of due to its stronger, non-corrosive microscope, which allows 25times magnification during the soldering process. This is possible because of its high stability from the tiny particle structure.

• Imaging Science in Dentistry
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• v.30 no.3
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• pp.199-205
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• 2000

Purpose: To determine whether the significant relationship exists between radiographic appearance, whether it is unilocular or multilocular, and its corresponding clinical and histologic features by examining the odontogenic keratocyst clinically, radiologically and histologically. Materials and Methods: This study was conducted on 48 cases of odontogenic keratocyst from the files of Dental Hospital, Yonsei University for the years 1982 through 1995. Results and Conclusions : The mean age of patients was 30.5 years in the unilocular group and 35.5 years in the multilocular group. The male to female ratio was 1 : 1.06 in the unilocular group and 1 : 1.75 in the multilocular group. The chief complaint was swelling in both groups(unilocular 35.1 %, multilocular 54.5%). In the occurrence site, the border of the lesion, the displacement and external root resorption of the adjacent teeth, there were no statistically significant difference between the unilocular group and multilocular group, but in the border type, there was statistically significant difference (x²-test, p<0.05)wo recurred cases were observed among 11 cases of odontogenic keratocyst. One was unilocular case and the other was multilocular case.

• Journal of Korean society of Dental Hygiene
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• v.3 no.2
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• pp.117-125
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• 2003

This study was pursued for the sake of gathering fundamental information to implement school-based comprehensive oral health care program and for planning oral health care program in consideration of parents. The following results were obtained by investigation of consciousness and favor level of 215 parents, who have elementary school children, regarding school-based comprehensive oral health care program. 1. It appears that many parents are not knowledgeable about school-based comprehensive oral health care program. There were significant differences between recognition level of school-based comprehensive oral health care program and age(PE0.05). 2. The parents acquired information about school-based comprehensive oral health care program; 58.7% by their children, 11.2% by mass-media, 10.0% by dentists and 3.7% by dental hygienists. 3. Most parents are in favor of school-based comprehensive oral health care program (96.7%). 4. Many parents(63.7%) prefer that social security law should budget for oral health care program. There were significant differences by sex(PE0.05) and age(PE0.01) As most parents are not so conscious of school-based comprehensive oral health care program, appropriate education program for dentists, dental hygienists and parents should be developed urgently.

• Journal of Korean Dental Science
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• v.7 no.2
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• pp.80-86
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• 2014

Purpose: Current common method of cytotoxicity evaluation for elastomeric impression materials use animal based cell lines, which the clinical relevance has been often questioned. Hence, the purpose of this study was to examine the difference in results with both human based and animal based fibroblast cell line. Materials and Methods: Three types of fibroblast cells were used in this study; conventional mouse fibroblasts of L929, human gingival fibroblasts (HGF-1), and immortalized human oral fibrobalsts (hTERT-hNOF). Test on extract and test by direct contact using different commercially available elastomeric impression materials were carried out according to the international standards. Result: There was significant difference in cell viability between types of fibroblasts cell used, where HGF-1 showed highest cell viability and L929 the lowest. Conclusion: Within the limitation of this study, careful consideration must be given when selecting the cells and interpreting the results for cytotoxicity evaluation of elastomeric impression materials, where use of human based cell lines such as hTERT-hNOF would be appropriate for both ease of cytotoxicity test and clinical relevance.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.9
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• pp.769-775
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• 2016

Currently, dental implants are widely used as artificial teeth due to their good chewing performance and long life cycle. Generally, a dental implant consists of an abutment as the upper part and a fixture as the lower part. When chewing forces are repeatedly applied to a dental implant, a gap is often generated at the interfacial surface between the abutment and the fixture, and it results in some deterioration such as loosening of the fastening screw, dental retraction and fixture fracture. To enhance the sealing performance for coping with such problems, this study proposes a new sealing-type abutment having a number of grooves along the conical surface circumference, and it carries out finite element analysis in consideration of the external chewing force and pretension between the abutment and the fixture. The result shows that the proposed sealing-type abutment shows an enhanced sealing performance in terms of the contact pressure in comparison with a conventional abutment.