• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.158-169
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• 2005

This study was done to evaluate the shear bond strength between light-cured glass ionomer cement (GIC) base and resin cement for luting indirect resin inlay and to observe bonding aspects which is produced at the interface between them by SEM. Two types of light cured GIC (Fuji II LC Improved, GC Co. Tokyo, Japan and Vitrebond$^{TM}$, 3M, Paul Minnesota U.S.A) were used in this study. For shear bond test, GIC specimens were made and immersed in 37$^{\circ}C$ distilled water for 1 hour, 24 hours, 1 week and 2 weeks. Eighty resin inlays were prepared with Artglass$^{(R)}$ (Heraeus Kultzer Germany) and luted with Variolink$^{(R)}$ II (Ivoclar Vivadent, Liechtenstein). Shear bond strength of each specimen was measured and fractured surface were examined. Statistical analysis was done with one-way ANOVA. Twenty four extracted human third molars were selected and Class II cavities were prepared and GIC based at axiopulpal lineangle. The specimens were immersed in 37$^{\circ}C$ distilled water for 1 hour, 24 hours, 1 week and 2 weeks. And then the resin inlays were luted to prepared teeth. The specimens were sectioned vertically with low speed saw. The bonding aspect of the specimens were observed by SEM (JSM-5400$^{(R)}$, Jeol, Tokyo, Japan) .There was no significant difference between the shear bond strength according to storage periods of light cured GIC base. And cohesive failure was mostly appeared in GIC On scanning electron micrograph, about 30 - 120 $\mu$m of the gaps were observed on the interface between GIC base and dentin. No gaps were observed on the interface between GTC and resin inlay.

• Journal of Korean Home Economics Education Association
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• v.19 no.3
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• pp.169-183
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• 2007

The purpose of this study is to examine the effects of self-esteem, relationships with parents and peer relationships on adolescents' school adjustment. Total of 900 middle school students residing in Guri, Geonggi-Do participated in the survey and the data collected from 874 students (557 male and 317 female students) were analyzed for this study. The followings summarize results of the study. First, the findings suggested that there is no significant difference between female and male students in school adjustment. Secondly, the study revealed that there is no difference between female and male students in self-esteem and relationship with parents. Thirdly, this study provided clear evidence that students with high self-esteem and close relationship with parents and schoolmates adapt to school life better than those with low self-esteem and distant relationship with parents and schoolmates. Fourthly, students with high self-esteem and close relationship with parents and schoolmates displayed higher adaptability to school life, and as for male students, close relationship with schoolmates was the most prominent factor which helps them adapt to school life better while female students' adaptability to school lifewas mainly affected by relationship with parents.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.65-74
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• 2009

It is expected that the number of apartment complexes in Korea that are over 20 years old will rapidly increase to more than 3,500,000. Consequently, the remodeling of these buildings is being revitalized throughout the country. Among the requirements for such remodeling, the expansion of parking lots has considerable weight. When enlarging a parking lot, the access route from an underground floor to the main building (i.e., the means of entry into the main building) determines the possibility of vertical enlargement for elevators, the size of the parking lot, the construction period, and construction expenses, etc. When enlarging an underground parking lot of an apartment complex, the access between the main building and the parking lot, as well as the inhabitants' requirements for entering the main building, are generally determined based on the designer's experience, rather than on the exact estimation of the peculiarity of the complex. In order to resolve such a problem, when enlarging an underground parking lot, a systematic and rational method is needed for selecting the means of entry into the main building. In this study, a selection model is derived for the method of selecting an access route into the main building when constructing an underground parking lot, in order to provide a reasonable decision-making process. A research method was investigated for determining the access route into the main building when enlarging a parking lot. On the basis of research carried out through in-depth interviews with experts, the characteristics for each means of entry into the main building were analyzed and the factors affecting the selection of the access route were deduced. The affecting factors selected were construction efficiency, convenience efficiency and economic efficiency. Weight values were then estimated for the selected affecting factors by applying the AHP method. Results showed that convenience efficiency, which gained the highest value, is the most important factor in selecting the means of entry into the main building. The most suitable means of entry into the main building was also suggested after estimating the applicability of the site by selecting complexes with remodeling possibility. This study will be applied as a reference for selecting the means of entry into the main building when constructing an underground parking lot particularly for older apartment complexes.

• Journal of Oral Medicine and Pain
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• v.34 no.1
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• pp.63-79
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• 2009

While previous epidemiological studies on temporomandibular disorders (TMD) have been based on a given health center or population sample, no study has been performed on general population of Korea, especially concerning about treatment pattern such as clinician’s specialty involved in TMD treatment, types and amount of prescription medication and cost. This study aimed to investigate magnitude of health visits and treatment patterns for Korean patients with TMD through the computerized database of Health Insurance Review and Assessment Service (HIRAS). Inclusion criteria were all patients registered on the HIRAS database over 3 years' period from 2003 to 2005 and the medical records of patients with TMD as a main diagnosis were extracted. Information collected was as follows; distribution related to gender, age and region and type of hospital the patients visited, treatment duration, clinicians' specialty involved in treatment, cost, types of prescription medication and surgical treatment. The results of this study indicated that 0.15% of the population yearly sought TMD treatment, presenting with increase of incidence over the three years. Most of TMD patients were women (99.8%) and the biggest age group was second and third decades and decreased with age. Seoul and Kyeonggi province presented with higher incidence of TMD compared to the other regions of Korea, which seems to be related with magnitude of population. 56% of TMD patients visited primary care sector and the numbers of treatment visits was the highest in dental clinic (38.4%), followed by orthopedics (28%) and ENT (13.6%) clinics in order. Duration of prescription medication was the longest for anti-inflammatory analgesics, followed by antipsychotic drugs and muscle relaxants. Inpatient care related to TMD was primarily performed in dental hospital compared to medical hospital. Medical database of HIRAS provided comprehensive and vast information on epidemiologic characteristics and treatment patterns for patients seeking TMD treatment, which can be more reliable data to expect medical demand for TMD in condition that accurate diagnosis and standardized treatment is delivered in clinical settings.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.152-161
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• 2007

This study was conducted to patients visited oral maxillo-facial surgery, KNUH and the purpose of the study was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction treated by skeletal Class III malocclusion patients with open bite versus non-open bite. This retrospective study was based on the examination of 40 patient, 19 males and 21 females, with a mean age 22.3 years. The patients were divided into two groups based on open bite and non-open bite skeletal Class III malocclusion patients. The cephalometric records of 40 skeletal Class III malocclusion patients (open bite: n = 18, non-open bite: n = 22) were examined at different time point, i.e. before surgery(T1), immediately after surgery(T2), one year after surgery(T3). Bilateral sagittal split ramus osteotomy was performed in 40 patients. Rigid internal fixation was standard method used in all patient. Through analysis and evaluation of the cephalometric records, we were able to achieve following results of post-surgical stability and relapse. 1. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in maxillary occlusal plane angle of pre-operative stage(p>0.05). 2. Mean vertical relapses of skeletal Class III malocclusion patients with open bite were $0.02{\pm}1.43mm$ at B point and $0.42{\pm}1.56mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.12{\pm}1.55mm$ at B point and $0.08{\pm}1.57mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in vertical relapse(p>0.05). 3. Mean horizontal relapses of skeletal Class III malocclusion patients with open bite were $1.22{\pm}2.21mm$ at B point and $0.74{\pm}2.25mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.92{\pm}1.81mm$ at B point and $0.83{\pm}2.11mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in horizontal relapse(p>0.05). 4. There were no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in post-surgical mandibular stability(p>0.05). and we believe this is due to minimized mandibular condylar positional change using mandibular condylar positioning system and also rigid fixation using miniplate 5. Although there was no significant relapse tendency observed at chin points, according to the Pearson correlation analysis, the mandibular relapse was influenced by the amount of vertical and horizontal movement of mandibular set-back(p=0.05, r>0.304).

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.3
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• pp.266-272
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• 2009

Statement of problem: The number of edentulous patients is increasing due to an aging society, which leads to increased demands and interests on implant restorations. Implant restorations are an effective treatment method for both complete and partially edentulous patients, and the success rate has been reported to be high. But because of the increased use of implants in various situations have resulted in frequent reports of failures on implant restorations. Various efforts to overcome these failures have been made. Purpose: The aim of this study was to investigate the statistic survival rate of dental implants on patients who were treated at Dankook University Dental Hospital during the past 10 years based on their charts. Materials and methods :The research was made for two different periods of time; The first investigation was for patients from August, 1998 to August, 2003 and the second was for patients from September, 2003 to April, 2007. Information on the number of implants placed, the location and distribution of implants, the duration between the first and second surgery, and the survival rate of implants were investigated from the patients'charts. Results: 1. According to the first investigation, 1680 implants were placed on 612 patients and the second investigation showed 2438 implants placed on 933 patients. Thus a total of 4118 implants on 1545 patients. 2. Among the 1545 patients, 884 patients were male (57.2 %) and 661 patients were female (42.8%). Out of 4118 implants, 1739 implants (42.2%) were placed on the maxilla, and 2379 implants (57.8%) on the mandible. Implants were placed most frequently in the posterior region of the mandible. A total of 2043 implants (53.2%) were placed in this region. 3. According to the first investigation, 57 out of 1680, implants failed, while from the second investigation, 17 out of 2438 implants were reported as failure. In total, 74 implants failed, which results in a 98.2% survival rate. 4. The average duration between the first and the second surgeries in maxillas decreased from 7.4 months to 6.8 months. The duration also decreased from 5.6 months to 5.0 months in mandibles. Conclusion: As shown in the results, the number of placed implants and the survival rate of implants were higher in the second investigation than that of the first investigation. And the time spent after the first surgery to the second surgery was less in the second investigation. Consequently, it can be presumed that the demand and consumption of dental implants as well as the survival rate will increase in the future.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.321-331
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• 2005

The purpose of this study was to compare the effectiveness of mechanical and acid treatment on enamel surfaces for the retention of pit and fissure sealants and evaluate the presence of a prismless layer. The etch pattern produced on enamel from immature and mature premolar teeth extracted with varying period of acid etching using 37% phosphoric acid was examined using a scanning electron microscope(SEM). The composition of each groups was evaluated using an energy dispersive x-ray(EDX) spectroscopy. The result of present study can be summarized as follows: 1. Prismless layer was commonly observed on the fissure enamel in young and mature premolar. 2. There were no differences in micro-structure and etching pattern on fissure enamel between the young and the mature premolar. 3. The most effective etching pattern for retention of pit and fissure sealant was observed in 60 seconds of etching time and no apparent difference of etching pattern was found among 15, 30, and 45 seconds of etching time which showed non-retentive etching patterns. 4. The etching pattern obtained by grinding enamel surface with bur followed by 60 seconds of etching was similar to that of 60 seconds of etching without any pretreatment of fissure surface. 5. Type 2 etching pattern was commonly found on fissure enamel in both young and mature premolar. 6. The calcium content and P/Ca ratio in fissure enamel between the young and the mature premolar were significantly different(P<0.05). But content of calcium, phosphate and P/Ca ratio on various regions of fissure enamel in both young and mature premolar did not showed any difference. Based on these results, prismless layer may negatively influence the retention of pit and fissure sealants. Therefore, the mechanical removal of the prismless layer by grinding prior to etching or by prolonged etching time of enamel within the fissure system should result in an improved bonding of a pit and fissure sealant.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.348-354
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• 2011

Composite resin has been widely used for eroded enamel. But, as there have been many reports about the differences in physicochemical characteristics of eroded enamel compared with sound enamel, an additional effort was thought necessary to obtain the optimal bond strength. As a possible answer, we came to think about the application of infiltrant resin which is known to have an excellent penetration capacity into enamel. This study was performed for the purpose of comparing the bond strength of composite restoration with or without infiltrant resin under adhesives on the artificially eroded enamel. 60 extracted sound maxillary primary incisors were selected and divided into group 1, 2, 3 according to the number of artificial erosion cycling for 5 minute duration in 1% citric acid of pH 3.2 at $37^{\circ}C$. And the labial surfaces were divided into 3 areas; group A, only resin adhesive was used, group I, only infiltrant resin, group IA, infiltrant resin followed by resin adhesive. Afterwards, every specimen was restored with composite resin. Microtensile bond strength was measured and failure modes were observed. The obtained results were as follows: 1. In comparing the bond strength by the degree of enamel erosion, it was revealed the highest bond strength in group 1, followed by group 2 and 3, showing the lowest bond strength in most eroded group(p<0.05). 2. In comparing the bond strength by surface treatment methods, group IA and I showed higher value than group A(p<0.05), with unsignificant difference between group I and IA(p>0.05). 3. In observation of failure mode, it was shown higher frequency of cohesive failure in order of 1-2-3 and IA-I-A. Conclusively, it was shown decreasing tendency of bond strength as the enamel is more eroded, and infiltrant resin was thought helpful to replace or add to the resin adhesive for optimal bonding with eroded enamel.

• Tuberculosis and Respiratory Diseases
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• v.53 no.3
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• pp.275-284
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• 2002

Background : Gemcitabine is a new anti-cancer agent for treating non-small cell lung cancer. Functioning as an antimetabolite, it induces anti-cancer effects by suppressing DNA synthesis after being incorporated into the DNA as a cytosine arabinoside analogue. When Gemcitabine is incorporated into the DNA, the p53 gene may be activated by induction of the DNA defect. However, there are a few studies on the molecular mechanisms of Gemcitabine-induced cell death. This study examined the role of p53 in Gemcitabine-induced cell death. Methods : A549 and NCl-H358 lung cancer cells were used in this study. The cell viability test was done using a MTT assay at Gemcitabine concentrations of 10nM, 100nM, 1uM, 10uM and 100uM. A FACScan analysis with propium iodide staining was used for the cell cycle analysis. Western blot analysis was done to investigate the extent of p53 activation. For the functional knock-out of p53, stable A549-E6 cells and H358-E6 cells were transfected pLXSN-16E6SD which is over expresses the human papilloma virus E6 protein that constantly degrades p53 protein. The functional knock out of p53 was confirmed by Western blot analysis after treatment with a DNA damaging agent, doxorubicine. Results : Gemcitabine exhibited cell toxicity in dose-dependent fashion. The cell cycle analysis resulted in an S phase arrest. Western blot analysis significant p53 activation in time-dependent manner. Gemcitabine-induced cytotoxicity was reduced by 20-30% in the A549-E6 cells and the 30-40% in H358-E6 cells when compared with the A549-neo and H358-neo control cells. Conclusion : Gemcitabine induces an S phase arrest, as expected for the anti-metabolite, and activates the p53 gene, Furthermore, p53 might play an important role in Gemcitabine-induced cell death. Further investigation into the molecular mechanisms on how Gemcitabine activates the p53 gene and its signaling pathway are recommended.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.38-43
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• 2006

Background : Even though two-month rifampicin (RMP, R) and pyrazinamide (PZA, P) treatment has some advantages over isoniazid (INH, H) treatment for latent tuberculosis infection (LTBI), it was withdrawn from the list of treatment regimens for LTBI because of reported cases of severe hepatotoxicity. The purpose of this study was to estimate the frequency of hepatotoxicity of RMP and PZA treatment excluding INH in a Korean population. Method : TIn order to recruit patients who were prescribed RMP and PZA excluding INH, 256 INH-resistant tuberculosis patients were investigated through retrospective medical record analysis. A standard four-drug regimen was changed to a RMP/PZA-containing regimen excluding INH in 64 patients (RZ+ group). In the same study period, 146 patients who were prescribed an INH/RMP/PZA-containing standard regimen were randomly selected as a control (HRZ+ group). Clinical characteristics including liver diseases and the frequency of drug-induced hepatitis were compared between the RZ+ and HRZ+ groups. Result : The mean age of patients in the RZ+ group was 50.2 (${\pm}16.2$) and the male-to-female ratio was 36:28. The frequency of underlying liver diseases was 10.9% (7/64), which was not significantly different from that of the HRZ+ group (4.1%, 6/146). Even though the treatment duration of RZ+ ($5.5{\pm}4.8months$) was longer that than that of HRZ+ ($2.7{\pm}2.3months$), the frequency of toxic hepatitis was not significantly different between RZ+ and HRZ+ groups, 3.5% (2/57) and 7.1% (10/140), respectively. Conclusion : Hepatotoxicity was mild and occurred in a minor proportion of patients in a Korean population prescribed an RMP/PZA-containing regimen. A future prospective study including more patients is needed.