• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.47-60
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• 2007

The purpose of this study is to compare and to evaluate the effect of pH and lactic acid concentration on the progression of artificial root caries lesion using polarizing microscope, and to evaluate the morphological changes of hydroxyapatite crystals of the demineralized area and to investigate the process of demineralization using scanning electron microscope. Artificial root caries lesion was created by dividing specimens into 3 pH groups (pH 4.3, 5.0, 5.5), and each pH group was divided into 3 lactic acid concentration groups (25 mM, 50 mM, 100 mM). Each group was immersed in acid buffer solution for 5 days and examined. The results were as follows : 1. Under polarized microscope, the depth of lesion was more effected by the lactic acid concentration rather than the pH. 2. Under scanning electron microscope, dissolution of hydroxyapatite crystals were increased as the lactic acid concentration increased and the pH decreased. 3. Demineralized hydroxyapatite crystals showed peripheral dissolution and decreased size and number within cluster of hydroxyapatite crystals and widening of intercluster and intercrystal spaces as the pH decreased and the lactic acid concentration increased. 4. Under scanning electron microscope evaluation of the surface zone, clusters of hydroxyapatite crystals were dissolved, and dissolution and reattachment of crystals on the surface of collagen fibrils were observed as the lactic acid concentration increased. 5. Under scanning electron microscope, demineralizatlon of dentin occurred not only independently but also with remineralization simultaneously. In conclusion, the study showed that pH and lactic acid concentration influenced the rate of progression of the lesion in artificial root caries. Demineralization process was progressed from the surface of the cluster of hydroxyapatite crystals and the morphology of hydroxyapatite crystals changed from round or elliptical shape into irregular shape as time elapsed.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.283-296
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• 2006

Along with the development of scientific technologies, health care has been growing remarkably, and as the social life quality improves with increasing interest in health, the demand for medical service is rapidly increasing. However, medical accident and medical dispute also are rapidly increasing due to various factors such as, increasing sense of people's right, lack of understanding in the nature of medical practice, over expectation on medical technique, commercialize medical supply system, moral degeneracy and unawareness of medical jurisprudence by doctors, widespread trend of mutual distrust, and lack of systematized device for solution of medical dispute. This study analysed 30 cases of civil suit in the year between 1994 to 2004, which were selected among the medical dispute cases in dental field with the judgement collected from organizations related to dentistry and department of oral medicine, Yonsei university dental hospital. The following results were drawn from the analyses: 1. The distribution of year showed rapid increase of medical dispute after the year 2000. 2. In the types of medical dispute, suit associated with tooth extraction took 36.7% of all. 3. As for the cause of medical dispute, uncomfortable feeling and dissatisfaction with the treatment showed 36.7%, death and permanent damage showed 16.7% each. 4. Winning the suit, compulsory mediation and recommendation for settlement took 60.0% of judgement result for the plaintiff. 5. For the type of medical organization in relation to medical dispute, 60.0% was found to be the private dental clinics, and 30.0% was university dental hospitals. 6. For the level of trial, dispute that progressed above 2 or 3 trials was of 30.0%. 7. For the amount of claim for damage, the claim amounting between 50 million to 100 million won was of 36.7%, and that of more than 100 million won was 13.3%, and in case of the judgement amount, the amount ranging from 10 million to 30 million won was of 40.0%, and that of more than 100 million won was of 6.7%. 8. For the number of dentist involved in the suit, 26.7% was of 2 or more dentists. 9. For the amount of time spent until the judgement, 46.7% took 11 to 20 months, and 36.7% took 21 to 30 months. 10. For medical malpractice, 46.7% was judged to be guilty, and 70% of the cases had undergone medical judgement or verification of the case by specialists during the process of the suit. 11. In the lost cases of doctors(18 cases), 72.2% was due to violence of carefulness in practice and 16.7% was due to missing of explanation to patient. Medical disputes occurring in the field of dentistry are usually of relatively less risky cases. Hence, the importance of explanation to patient is emphasized, and since the levels of patient satisfaction are subjective, improvement of the relationship between the patient and the dentist and recovery of autonomy within the group dentist are essential in addition to the reduction of technical malpractice. Moreover, management measure against the medical dispute should be set up through complement of the current doctors and hospitals medical malpractice insurance which is being conducted irrationally, and establishment of system in which education as well as consultation for medical disputes lead by the group of dental clinicians and academic scholars are accessible.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.387-393
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• 2016

This study was conducted to examine the oral health awareness, needs of dental treatment and the oral and maxillofacial pains targeting pneumoconiosis patients of care hospitals for the purpose of providing basic data for preparing a plan to improve the oral health of patients plagued with pneumoconiosis. As the subjects of survey, total 120 patients who have agreed to the research among the patients of three care hospitals, were enrolled between March and July in 2015. As the result of the study on the factors that influence the oral health perception, it was verified that the persons of an average monthly income of 2 million won or more, were shown to have significantly better oral health awareness than the subjects of monthly earning of less than 2 million won (p<0.05), thus showing that the oral health awareness by the people of monthly income of more than 2 million won, was 0.77 times higher compared to the others. Therefore, in order to improve the oral health awareness of pneumoconiosis patients, the economic stability of the patients should be taken into account as a priority when examining the oral health policy decisions and it was recommended that the survey and research on the oral health of patients with pneumoconiosis can be done in amore systematic manner.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.643-655
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• 2000

In Patients with severe skeletal discrepancy, surgical orthodontic treatment must be accompanied, and recently two jaw surgery has become a common procedure, resulting in improved esthetics and function. Choosing the position of the occlusal plane in this two jaw surgery is an important factor in postoperative stability Therefore this must be taken into consideration during the diagnosis and treatment plan. In this study, among patients with skeletal Class III occlusion, 25 patients(8 male, 17 female, average age $23.2{\pm}3.17$) who have undergone two jaw surgery, setting the ideal occlusal plane according to Delaire's architectural and structural cranial analysis. In comparing preoperative($T_1$). postoperative($T_2$, average of 15.4 days), and long-term postoperative($T_3$, average of 32.6 months) lateral cephalometric radiography, the following conclusions have been made. 1. There were no significant changes of the occlusal plane angle after the two jaw surgery, and there were no significant differences between the surgical technique(SSRO and IVRO). 2. The postoperative changes of the occlusal Plane had no relationship with the amount of jaw movement, amount of posterior impaction, nor the time relapse after surgery. 3. After two jaw surgery, in the SSRO group there was significant forward movement of the mandible, and in the IVRO group the lower incisors extruded as the mandible moved backward and downward which makes the genial angle and the mandibular plane angle significantly increased

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.95-105
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• 2001

The present study was designed to compare morphological and structural relationships between basicranial measurements such as MCF angulation (Ar-SE-ptm), saddle angle (N-S-Ba, N-S-Ar) and facial structures including types of malocclusion. Twenty six children with Class III whose longitudinal headfilms were available from 7 to 12-year-old, and also 26 cross-sectional headfilms at each ages of 8, 9, 10 and 11 with Class I were selected for the investigation. Cephalometric measurements such as Ar-SE-ptm, N-S-Ba, N-S-Ar, N-SE-Ar, SNA, SNB, N-S/PM vert, CP/PM vert, $\underline{1}/FH$ plane, and $N-perp/\underline{1}$ were measured. Morphologic relationships and pattern of changes in facial structures in relation to the changes of MCF and saddle angle in both malocclusion types were analysed statistically employing ANOVA, t-test and Pearson correlation. Results suggest that the MCF rather than the saddle angle in children with Class I and III is more closely related with various facial structures and with their changes. It may be, therefore, suggested that the MCF be one of the biologically meaningful measurements in determining structural relationships between cranial base and facial complex including types of malocclusion. In addition, the MCF and its correlated facial structures in children with Class III, interestingly, showed somewhat marked changes between the ages of 9 and 11.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.80-91
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• 2003

Mutans streptococci, especially S. mutans and S. sobrinus strongly implicated in pathogenesis of dental caries, the major cause of tooth loss in children. Use of an antibacterial agent controlling dental caries has been rationalized. The present study was performed to observe the antibacterial effect of inorganic polyphosphates (polyP) on S. mutans and S. sobrinus. S. mutans GS5 and S. sobrinus 6715 were grown in brain-heart infusion broth with or without polyP. Minimal inhibitory concentration (MIC) of polyP for S. mutans GS5 was determined to be 0.08% and that for S. sobrius 6715 was 0.17%. PolyP 15 added to the growing culture of S. mutans GS5 and S. sobrinus 6715 at their exponential phase was as effective in inhibiting the growth of S. mutans GS5 and S. sobrinus 6715 as polyP added at the very beginning of the culture. More than 85% of the cells lost their viability determined by viable cell count when polyP 15 was added to the culture of growing S. mutans GS5 at MIC, suggesting that polyP 15 has bacterial effect on the bacterium. And more than 99.9% of the cells lost their viability determined by viable cell count when polyP 15 was added to the culture of growing S. sobrinus 6715 at MIC, suggesting that polyP 15 has bacterial effect on the bacterium. Intracellular nucleotide release from S. mutans CS5 and S. sobrinus 6715 was increased in the presence of polyP 15 for 5h but was not really reversed by the addition of divalent cations like $Ca^{++}\;and\;Mg^{++}$. The majority of the cells appeared to be atypical in their shape, demonstrating accumulation of highly electron-dense granules and ghost cells. The overall results suggest that polyP have a strong bactericidal activity against S. mutans and S. sobrinus in which lysis in relation to chelation may not play the major role but unknown mechanism that possibly affects the viability of the bacterium may be involved. PolyP may be used as an agent for prevention of dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.516-522
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• 2008

In the case of the impacted teeth, the clinician has to consider development of tooth, site of impaction, eruption path, and cooperation of patient. If there are genetic or general factors to effect the eruption of tooth, the clinician treats these first and then takes the early treatment for eruption guidance. If there are physical factors to intercept eruption, the clinician put them off first. However, if there are no factors to effect eruption of tooth and enough space for eruption, the clinician can consider extraction of deciduous teeth, forced eruption and surgical reposition. In case of surgical repositioning, proper time for root development, proper socket formation, and minimal trauma are important for success. This case presents displaced impacted maxillary central incisor with dilacerated root. The development of root is Nolla's stage 7, and the tooth was treated by surgical repositioning. We can observe no root resorption and good healing pattern.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.593-600
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• 2009

In this study, disabled people's life quality according to their use of dental healthcare services were examined, and the factors that influence their life quality were examined. The subjects in this study were 198 domestic disabled people in Jeollabuk-do, on whom a survey was conducted from May 1 to June 1, 2008. After the collected data were analyzed with SPSS WIN 12.0 program, the following findings were acquired: 1. 68.2% of the subjects had an experience of using dental service institutes. Over 80.0% of the physically disabled, the mentally handicapped, and the sensory-disturbance sufferers each used dental service institutes in their locations. Regarding the reason for visiting dental service institutes, 43.4% of the physically disabled visited for regular examination (the largest group for that reason), followed by the mentally handicapped with 37.9%. 43.5% of the sensory-disturbance sufferers visited for pain and fracture. 2. The subjects' life quality level relating to oral health was found to be an average 3.39 point score. There was a statistically significant difference in their life quality levels in terms of demographic features, such as age, religion, marriage/non-marriage, education, and subjective health status variables. Those experienced in using dental service institutes enjoyed higher levels of life quality (p=.011). And, with regard to disability characteristics, the degree of disability and the period of disability influenced the quality of life with a statistical significance. 3. Regarding variables influencing the life quality of subjects, in terms of general characteristic variables, subjective health status were influential variables, and in terms of characteristic variables relating to the use of dental clinics and disability, the experience of using dental service institutes influenced the quality of life. In conclusion, nationwide efforts to nurture separate dental personnels responsible for the disabled, to expand relevant facilities and to improve the health care insurance are required to promote the oral health of domestic disabled people's.

• Journal of dental hygiene science
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• v.8 no.2
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• pp.57-63
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• 2008

This study conducted a questionnaire survey for some local senior populations in Jeonbuk province, Korea, and came to the following conclusions: This study analyzed possible differences in elders' oral health beliefs and oral health behaviors depending on their general characteristics. As a result, it was found that there were significant differences in their oral health beliefs depending upon their religion, academic career and oral health conditions. It was found that high oral health beliefs group showed more significant differences in 'toothbrushing' and 'diet control' than low oral health beliefs group(p < .05). It was found that active oral health behavior group had higher quality of life than inactive oral health behavior group(p < .05), and 'regular visit of dental clinic' was a critical determinant of life quality(p < .05).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3451-3457
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• 2009

The survey of the 856 students of the dental hygiene departments in 6 universities in Gyunggi, Kangwon, Chungnam, Gyungbuk, and Gyungnam region was carried out. The purpose of the survey is to find their satisfaction measurement with the department and how they recognize the dental hygienist as well as why they selected the dental hygiene department when they applied for university. The result, analyzed by SPSS 15.0, statistically shows that the measurement of satisfaction by each academic year represents the meaningful difference (P<0.05) in all variables such as the "satisfaction with people", "satisfcation with lectures", "satisfaction with facilities", "satisfaction with activities", and "satisfaction with the department characteristic". The measurement of satisfaction by the decision-making factor for the department selection shows the meaningful difference (P<0.05) in the variables of "satisfaction with lectures", "satisfaction with activities", and "satisfaction with the department characteristic". In the case of the measurement of satisfaction with counselling by each academic year, the 3rd year student shows the highest in the career counselling. All the groups recognize for this question as "higher" or "yes", while the higher academic year students were gradually less satisfied. In the case of the level of recognition by each academic year, the 1st year student shows high in the variables of "practical work recognition" and "vocation recognition" and the difference among groups shows statistically meaningful difference(P<0.05).