• The korean journal of orthodontics
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• v.42 no.4
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• pp.207-217
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• 2012

Objective: This study aimed to evaluate the effect of an intentionally created socket on bone remodeling with orthodontic tooth movement in rabbits. Methods: Eighteen male rabbits weighing 3.8 - 4.25 kg were used. An 8-mm deep and 2-mm wide socket was drilled in the bone 1 mm mesial to the right mandibular first premolar. The left first premolar was extracted to serve as an extraction socket. A traction force of 100 cN was applied to the right first premolar and left second premolar. Sections were obtained at the middle third of the moving tooth for both the drilled and extraction sockets and evaluated with hematoxylin and eosin staining and immunohistochemical analyses. The amount of tooth movement and tartrate-resistant acid phosphatase (TRAP)-positive cell count were compared between the 2 groups using the Mann-Whitney U test. Results: At week 2, the distance of tooth movement was significantly higher in the intentional socket group (p < 0.05) than in the extraction socket group. The number of TRAP-positive cells decreased in week 2 but increased in week 3 (p < 0.05). However, there were no significant differences between the groups. Furthermore, results of transforming growth factor (TGF)-${\beta}$ staining revealed no significant differences. Conclusions: The intentional socket group showed greater distance of tooth movement than did the extraction socket group at week 2. Osteoclast counts and results of immunohistochemical analyses suggested elevated bone remodeling in both the groups. Thus, osteotomy may be an effective modality for enhancing tooth movement in orthodontic treatment.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.270-277
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• 2013

PURPOSE. This study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals. MATERIALS AND METHODS. Two commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of $15mm{\times}10mm$ dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant. RESULTS. Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed. CONCLUSION. Silicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners.

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.388-395
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• 2016

PURPOSE. The purpose of this study was to evaluate the resistance to deformation under static overloading by measuring yield and fracture strength, and to analyze the failure characteristics of implant assemblies made of different titanium grades and connections. MATERIALS AND METHODS. Six groups of implant assemblies were fabricated according to ISO 14801 (n=10). These consisted of the combinations of 3 platform connections (external, internal, and morse tapered) and 2 materials (titanium grade 2 and titanium grade 4). Yield strength and fracture strength were evaluated with a computer-controlled Universal Testing Machine, and failed implant assemblies were classified and analyzed by optical microscopy. The data were analyzed using the One-way analysis of variance (ANOVA) and Student's t-test with the level of significance at P=.05. RESULTS. The group $IT4_S$ had the significantly highest values and group IT2 the lowest, for both yield strength and fracture strength. Groups $IT4_N$ and ET4 had similar yield and fracture strengths despite having different connection designs. Group MT2 and group IT2 had significant differences in yield and fracture strength although they were made by the same material as titanium grade 2. The implant system of the similar fixture-abutment interfaces and the same materials showed the similar characteristics of deformation. CONCLUSION. A longer internal connection and titanium grade 4 of the implant system is advantageous for static overloading condition. However, it is not only the connection design that affects the stability. The strength of the titanium grade as material is also important since it affects the implant stability. When using the implant system made of titanium grade 2, a larger diameter fixture should be selected in order to provide enough strength to withstand overloading.

• International Journal of Oral Biology
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• v.41 no.4
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• pp.243-251
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• 2016

This study was undertaken to achieve a high bleaching efficacy with plasma, through longer application and reparative bleaching processes, by different shade evaluation methods. Extracted human teeth were divided into 6 groups (n=10). All teeth were treated in pairs. Low concentration of 15% carbamide peroxide (CP) was applied, with and without plasma, for 10, 20, and 30-min tooth bleaching, respectively. The bleaching procedure was repeated once daily for four days. The teeth were maintained in a moist environment provided by artificial saliva. The Vitapan Classical shade guide and Commission Internationale de L'Eclairage (CIELAB) color system were collectively used to measure the bleaching efficacy. Color evaluation was statistically analyzed using Student t-test and one-way analysis of variance (ANOVA) complemented by Tukey's test. Combining the plasma with 15% CP showed significantly greater color changes compared to bleaching without plasma (p<0.05). A high bleaching efficacy with plasma is proportional to the repetitive application and the treatment time. A 30-min application with plasma provided the best bleaching. Repetitive bleaching showed lower probability of color relapse of the bleached tooth. The color change by shade guide correlated with the changes in CIELAB color system. A value of 1 color change units (CCU) conversion factor for overall color change (${\Delta}E$) values comparisons was 3.724 values. The two measuring methods provide a more accurate correspondence of color change. The repetitive and longer application for tooth bleaching, combined with plasma, has a strong bleaching effect and produces whiter teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.1
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• pp.1-14
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• 1992

The purpose of this study was to evaluate the accuracy of reproduction of stone casts made from complete-arch impressions using different trays. The trays used were : 1) nonperforated custom tray, 2) perforated custom tray, 3) nonperforated Rim-Lock tray, 4) perforated stock tray. Impressions were made from an dentulous acrylic resin model with metal inserts in first premolars and second molars. Transverse distance, sagittal distance and diagonal distance were measured using 4 landmarks. Measurements were made by using 3 dimensional measuring machine. The impression material used was an addition silicone. Impressions were poured at once with a Type IV dental stone. Data were analyzed using ANOVA and student t-test with a sample size of five. The results were as follows : 1. There were statistical differences in amount of dimensional change in according to the tray types. In amount of mean dimensional change, perforated custom tray was the first smallest, nonperforated custom tray was the second, nonperforated Rim-Lock tray and perforated stock tray were the largest. 2. There were statistical differences in amount of dimensional change between nonperforated custom tray and nonperforated Rim-Lock tray, and between perforated custom tray perforated stock tray. 3. There were satistical differences in amount of dimensional change between nonperforated custom tray and perforated custom tray, but there was not a statistical difference between nonperforated Rim-Lock tray and perforated stock tray. 4. There was not a statistical difference in amount of dimensional change between upper and lower arch in all tray types.

• Korean Journal of Health Education and Promotion
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• v.33 no.1
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• pp.41-48
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• 2016

Objectives: This study is aimed to evaluate oral health knowledge and behavior according to subjective awareness characteristics of oral health in university student. Methods: The data was collected from June, 2015 in K university, Korea. It was investigated about subjective awareness characteristics, knowledge and behavior of oral health by questionnaires in university students. The data was analysis into t-test and one-way ANOVA by SPSS 22.0. Results: Subjects who responded that they had a problem with oral health in subjective awareness characteristics were a statistically significant differences according to gender. Subjects who were interested of oral health and responded to their subjective oral health state as good condition were higher than the others in oral health knowledge. According to subjective awareness characteristics of oral health, the oral health behaviors were a statistically significant differences. Conclusions: There were statistically significant differences in oral health knowledge and behavior according to subjective awareness characteristics of oral health.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4169-4172
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• 2015

Background: Oral carcinoma (OC) remains as one of the most difficult malignancies to cure. Hesa-A is an Iranian herbal-marine compound that has shown promising anti-tumor properties on various human cancer cells, although the mechanisms of action remain to be addressed. This study was conducted to evaluate the effect of two doses of Hesa-A on mRNA expression of p53 as a main prognosticator of OC. Materials and Methods: 60 rats were randomly divided into 5 groups of 12 animals each. Rats in carcinoma groups received 0, 250 and 500 mg/kg body weight of Hesa-A three times a day. The two other groups considered as treated and untreated healthy groups. At the end of experiment, animals were sacrificed and tongue tissues subjected to H and E staining and real time PCR. Results: Our results indicated that compared to healthy group, p53 over expressed ~ 40% in untreated carcinoma group. After treatment with 250mg/kg and 500mg/kg body weights of Hesa-A, p53 level dropped by 53.4% and 13.6 %, respectively, compared to untreated carcinoma group (p<0.05, p<0.0001). Moreover, there was a significant relation between p53 mRNA content and observed pathological changes in studied groups (p<0.05). Conclusions: These data provide insights into the mechanism(s) by which Hesa-A improves clinical outcome of oral carcinoma by modulation of p53 expression.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3601-3604
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• 2016

Background: The monocyte chemoattractant protein-1 (MCP-1/CCL2) is a potent chemoattractant for natural killer cells, monocytes, and memory T lymphocytes. However, any role in the genesis of salivary gland tumors (SGT) is unknown. To assess the diagnostic relevance of chemokines in SGT, MCP-1 levels in the serum of patients were investigated in association with tumor progression and clinical aggressiveness. Materials and Methods: Using an ELISA kit, we assessed and compared the circulating levels of MCP-1 in blood serum of 70 SGT patients with 44 healthy control samples. Results: The results of this study showed that the concentration of MCP-1 was significantly lower in patients with benign ($463.8{\pm}158.5pg/ml$, P=0.033) and malignant ($454.8{\pm}190.4pg/ml$, P=0.007) SGT than in healthy subjects ($645.7{\pm}338.9$). No significant difference in mean serum levels of MCP-1 was observed between the benign and malignant group (p=0.9). While MCP-1 levels were lower in patients with an advanced clinical stage, advanced tumor size, higher tumor grade, or lymph node involvement, but the mean MCP-1 level between groups showed no statistically significant difference (p>0.05). Conclusions: MCP-1 levels in the serum of patients with SGT were decreased, indicating that this might a good marker for discriminating patients with SGT from healthy people. However, no clear-cut relationship was detected between MCP-1 levels and clinicopathologic factors, and MCP-1 is not a good marker for evaluating tumor dissemination.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.447-459
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• 1994

The purpose of this study is to evaluate of shear bond strength of light-curing composite resin to light-curing glass ionomer cement. Composite resin and glass ionomer cement have been widely used as an esthetic filling materials in dental clinics. To achieve better clinical results, sandwich technic was developed with conpensating for disadvantages of these two materials. Especially, light-curing glass ionomer cement provided greately improved bonding strength of teeth or composite resin, and then excellent clinical results can be acquired. In this study, 6 commercial light-curing glass ionomer cements(3 commercial restorative materials : Fuji II LC, Variglass VLC, Vitremer, and 3 commercial lining materials : Fuji Lining LC, Baseline VLC, Vitrebond) were devided two groups. According to manufacturer's appointment, no surface treatment was referred to N groups. Supposing. of clinical practice, surface grinding with water spray at 320 grit sand paper, 40 seconds etching with 37% phosphoric acid, 20 seconds washing, 20 seconds air drying was referred to N groups. Totally 12 experimental groups were devided, and all 120 specimens from 10 specimens of each groups were made. After light-curing composite resin was bonded to light-curing glass ionomer cement, shear bond strength was tested by Instron universal testing machine between glass ionomer cement and composit resin. The data were analyzed statistically by Student's t-test and ANOVA. The obtained results were as follows; 1. In light-curing glass ionomer cement, restorative materials showed higher shear bond strength to composite resin than lining materials(p<0.05). 2. Variglass VLC of restorative material group and Baseline VLC of lining material group have highest shear bond strength to composite resin(p<0.001). 3. In light-curing glass ionomer cement, surface grinding and acid etching reduced shear bond strength to composite resin(p<0.001)}. 4. VGN group 1s highest shear bond strength to composite resin, VBE group is lowest shear bond strength to composite resin(p<0.001).

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.91-98
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• 2015

Recent domestic university has emerged need to convergence education. Health related department College students must deal with a lot of exams. The test anxiety can cause physiological and psychological problems. To solve this problem, it is necessary examine the relationship between test anxiety and self-esteem. This study Health related department College students conducted questionnaire survey of 301 students. In general the overall average is 2.98 according to the characteristics of self-esteem and gender, boys, if older, the older the more self-esteem was higher. Test anxiety of the general characteristics showed little higher this year. Test anxiety is higher self-esteem was low. The effect o the general characteristics and test anxiety self-esteem, in the case of boys, seniors, if I choose this self-esteem was higher, the higher the anxiety test were analyzed by low self-esteem. Therefore, need to a systematic curriculum approach and academic environment.