• Applied Microscopy
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• v.34 no.2
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• pp.145-157
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• 2004

The aim of the present study was to examine in detail, both at light and electron microscopical levels, the morphological variations in ameloblast of the fetal rat incisor enamel organ. Rats were started on distilled water at the beginning of pregnancy. The pups were sacrificed 11 days after delivery and animals were perfused intravascularly with glutaraldehyde and the incisors were removed. To examine on the ultrastructure of the ameloblast, the study employed primary light microscopy but electron microscopy was used to clarify some of the light microscopic finding. Longitudinal sections through the incisors of the rat show a continuous layer of ameloblasts on the labial surface of the tooth. This layer contains the entire sequence of developmental stages in enamel production. The ameloblast layer was divided into three main zones: 1) Presecretory zone, region of ameloblasts facing pulp. 2) Secretory zone, region of inner and outer enamel secretion. 3) Maturation zone, region of reduced ameloblasts. In particularly, the present study has shown that two distinctively different types of ameloblasts appear in the enamel organ during enamel maturation in the rat incisor. These two types have been designated ruffle-ended ameloblasts (rAB) and smooth-ended ameloblasts (sAB). The fluoride produces marked alteration in the fine structure of ameloblast from teeth of young rats, such as large confluent distensions of the endoplasmic reticulum and swelling of isolated mitochondria. This experimental data suggested that exposure prolonged of animal to high level of fluoride appears to induce a few dramatic changes in the normal appositional growth and initial mineralization of enamel created during amelogenesis.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.313-320
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• 2010

Objectives: The aim of this study was to examine changes in the dentinal fluid flow (DFF) during desensitizing agent application and to compare permeability after application among the agents. Materials and Methods: A Class 5 cavity was prepared to exposure cervical dentin on an extracted human premolar which was connected to a sub-nanoliter fluid flow measuring device (NFMD) under 20 cm water pressure. DFF was measured from before application of desensitizing agent (Seal&Protect, SP; SuperSeal, SS; BisBlock, BB; Gluma desensitizer, GL; Bi-Fluoride 12, BF) through application procedure to 5 min after application. Results: DFF rate after each desensitizing agent application was significantly reduced when compared to initial DFF rate before application (p < 0.05). SP showed a greater reduction in DFF rate than GL and BF did (p < 0.05). SS and BB showed a greater reduction in DFF rate than BF did (p < 0.05). Conclusions: Characteristic DFF aspect of each desensitizing agent was shown in NFMD during the application procedure.

• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.537-550
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• 2009

During the last two decades, there has been an increasing interest in the impact of oral health on atherosclerosis and subsequent cardiovascular disease (CVD). To date, some periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) have been reported to be relevant to CVD. Porphyromonas endodontalis (P. endodontalis), which shares approximately 87% sequence homology with P. gingivalis, is mostly found within infected root canals. However, recent studies reveal that this pathogen also resides in the dental plaque or periodontal pocket in patients with periodontitis. It has been shown that P. endodontalis invades human coronary artery endothelial cells (HCAEC) and coronary artery smooth muscle cells (CASMC). To evaluate whether P. endodontalis can participate in the progression of atherosclerosis and CVD, we examined the changes in transcriptional gene expression profiles of HCAEC responding to invaion by P. endodontalis in this study. The following results were obtained. 1. Porphyromonas endodontalis was invasive of HCAEC. 2. According to the microarray analysis, there were 625 genes upregulated more than two-folds, while there were 154 genes downregulated by half. 3. Upregulated genes were relevant to inflammatory cytokines, apoptosis, coagulation and immune response. Enhanced expression of MMP-1 was also noticeable. 4. The transcription profiles of the 10 selected genes examined by real-time PCR agreed well with those observed in the microarray analysis. Thus, these results show that P. endodontalis presents the potential to trigger and augment atherosclerosis leading to CVD.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.187-193
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• 2016

In this study, we performed the carotid artery ultrasound targeting 140 subjects who have conducted to evaluate the changes in intima-media thickness(IMT) and plaque correlated with the presence or absence of a hematological test of the carotid artery. Considering that the IMT thickness more than 1mm is abnormal based on the carotid artery ultrasound to assess the presence or absence of plaque, and examined the correlation by classifying the blood lipid value and the fasting blood glucose level through the serum test. Consequently, the fasting blood glucose level is being analyzed as independent predictors of causing dental plaque(p=0.033), cut off value was determined as 126 mg/dL(sensitivity 56.25%, specificity 68.38%) in ROC curve analysis. Furthermore, the odds ratio appeared 1.01 times the value in the Logistic regression. Therefore, it seemed that the necessity to prospective studies in a number of subjects are considered, and also taking into account a number of blood test values along with the sonography of the carotid artery as a valuable part for effective primary prevention and follow-up observation of the cardiac and brain vascular disease is highly recommended.

• Biomedical Science Letters
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• v.25 no.3
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• pp.218-226
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• 2019

In old age, measures to cope with the natural phenomenon of aging and various diseases of the elderly due to the deterioration of physical function are also a challenge for this society. While interest in systematic health is increasing, it is true that awareness and interest in oral-related diseases is relatively lacking. This study aims to present basic data necessary to improve the quality of life for senior citizens aged 65 or older by improving the oral dryness caused by systemic health. By research method, improve oral dryness caused by whole-body health with the elderly over 65 and promote their oral health, inducing the increase of the salivary flow rate through oral health care education, oral exercise, and salivary gland massage. First, on the DMSQ according to the general characteristics of the elderly, the recognition of the whole body and oral health status, independent sample t-test and One-way ANOVA were conducted. Second, on changes in the salivary flow rate and saliva pH according to the general characteristics of the elderly, recognition of oral and whole-body health status, and whole-body health, paired samples t-test was conducted. Studies have shown that salivary gland flow increased significantly after oral exercise and salivary gland massage, the salivary flow rate significantly increased. In all variables of the recognition of the oral health status, the salivary flow rate increased after oral exercise and salivary gland massage, and in the whole-body health, regardless of hypertension, diabetes, cardiovascular disorders, and osteoporosis, the salivary flow rate increased after oral exercise and salivary gland massage, and the salivary flow rate increased after oral exercise and salivary gland massage if the subjects responded that they did not have thyroid abnormality, anemia, abnormalities of breathing, hypotension, gastrointestinal disturbance, or kidney diseases. As a comprehensive analysis of this study, many felt oral dryness when they had a problem with the whole-body health, and many felt oral dryness when they had a problem with oral health cognition. After applying oral exercise and salivary gland massage as intervention methods in the oral health care for the elderly, the salivary flow rate significantly increased, and it is judged that the methods were very effective for controlling oral dryness. Furthermore, it is judged that the factors affecting oral health, whole-body health, and oral dryness would be identified, which would be helpful for the promotion of whole-body health and oral health. It is judged that continuous research would be needed so that measures for the application of the oral care program and system for the elderly would be prepared in the future.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.1
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• pp.85-92
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• 2019

The purpose of this study was to compare and evaluate the cytotoxicity of 3 calcium silicate-based materials (CSMs) on stem cells from human exfoliated deciduous teeth (SHEDs). The powder of Retro $MTA^{(R)}$ (RM), $EZ-Seal^{TM}$ (EZ) and ENDOCEM $Zr^{(R)}$ (EN) was eluted with SHED culture media and then filtered. The SHEDs were cultured in the presence of the various concentrations of the eluate. To investigate the effect of the 3 CSMs on SHED proliferation, the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay was performed. Flow cytometry analysis was also performed to identify any changes in the cellular phenotype. The absorbance values of the SHEDs cultured in the eluate of samples at a 10% concentration showed the following relation: RM > EN > EZ (p = 0.0439). However, the SHEDs maintained their mesenchymal phenotype regardless of product exposure. Although the 3 CSMs did not alter the SHED stem cell markers, EZ may be a less cytocompatible than RM and EN.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.491-498
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• 2021

In this study, the effective dose was measured using the PCXMC v2.0 program by examining the conditions used to set the diagnostic reference level for intraoral imaging recommended by the government, and the effect of the Al additive filter was confirmed. In oral imaging, the largest effective dose was calculated from the oral mucosa among 11 organs. The effect of the Al additive filter showed an excellent radiation reduction effect at 2mm rather than 1mm. In the case of children aged 5 years, the overall effective dose was calculated to be high in all 11 organs because they are more sensitive to radiation than adults. And as a result of evaluating the image quality according to the use of an additional filter during intraoral imaging, there was no significant difference in SNR and CNR changes compared to before the additional filter was used. Based on this study, it is thought that additional filter settings can be recommended for intraoral imaging.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.671-680
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• 2022

The purpose of this study is to suggest the direction of the funeral culture industry suitable for the age of longevity and well-aging through a study on changes in the perception of funeral culture among the elderly. The survey of this paper was conducted by Gallup Korea, and the survey method was a 1:1 individual interview using a structured questionnaire. The survey was conducted from October 1 to October 25, 2021, targeting 127 elderly people over the age of 65 living in Seoul, Incheon, and Gyeonggi-do. The number of valid subjects was 110, and the sampling method used was allocation by sex/age/income level/religion. As a result of the study, as for the change in the perception of funeral culture among the elderly, women preferred cremation to men (p=0.034). It was investigated that the level of income (p=0.004) and religious status (p=0.020) had an effect on funerals while alive. According to the presence or absence of thoughts about death, there was a significant difference in the membership of the mutual aid product (p=0.008) and the intention to return to a religious organization (p=0.004) when a memorial service was held. The results of this study are expected to be usefully utilized in presenting the direction and policy of the funeral culture industry suitable for the age of well-aging in the future.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.30 no.2
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• pp.53-58
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• 2021

The attractiveness of the gingiva is determined by its color, shape, and the shape and location of the boundary between the teeth and the gingival tissue. The standards beauty, balance, and health of the gingiva are all different, but the general public would agree that a coral pink gingiva is more beautiful than black or brown gingiva. Hence, one would be able to smile more confidently in public if he or she receives a gingival pigmentation removal surgery that changes the color of black or brown gums to a beautiful pink color with relative simplicity. The color of one's gingiva varies from pale pink to deep bluish purple, depending on many health components. The most prominent among these include the vascular supply, epithelial thickness, the degree of keratinization, and the presence of pigment in the epithelium. Melanin, carotene, reduced hemoglobulin, and oxyhemoglobulin are the main pigments contributing to the normal color of the oral mucosa. The health of one's gingival tissue are essential for an attractive smile. Excessive melanin deposits in the basal and early basal layers of the epithelium stored in the form of melanosomes frequently cause pigmentation. Although there are many different procedures to remove this pigmentation, the it was removed using the Er;YSGG laser. It is my wish that, through this case study, many people

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.2
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• pp.155-167
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• 2023

The aim of this study was to investigate the effects of slow maxillary expansion (SME) on the dentoalveolar, skeletal, upper airway, and maxillary sinus using cone-beam computed tomography (CBCT). Twenty-three orthodontic patients (mean age 8.93 ± 1.61 years) who were treated with maxillary expansion using banded hyrax in the Department of Pediatric Dentistry at Jeonbuk National University Dental Hospital were included. According to the expansion speed applied, they were divided into two groups: SME (12 subjects, mean age 8.92 ± 1.45 years) and rapid maxillary expansion (RME, 11 subjects, mean age 8.94 ± 1.84 years). CBCT were obtained before (T0) and after (T1) the treatment and were analyzed with InVivo5 software (Anatomage, San Jose, CA, USA). Descriptive statistics showed no significant differences between the two groups in age, sex, or skeletal maturity. There were significant increases in maxillary width at the dentoalveolar and skeletal levels for both groups. Upper airway volume revealed a significant increase of 38.59% in the SME group and 28.72% in the RME group. However, there was no significant difference between SME group and RME group in all measurements. This study suggested the efficacy of SME in growing patients. SME was effective in increasing not only dentoalveolar and skeletal measurements but also airway volume. Therefore, pediatric dentists should select an appropriate expansion method considering the physiological aspects of periodontal tissues and discomfort in growing children.