• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.1-7
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• 2015

Acute phase patients who are unconscious and are suffering from cerebral infarction, cranial nerve disorders, or cerebral apoplexy are susceptible to aspiration pneumonia due to dysphagia. In these cases, a nasogastric tube is inserted to supply nutrients. Although bedside screening tests are administered during recovery after rehabilitation, clinical examinations may not be able to ascertain asymptomatic aspiration. Therefore, a video fluoroscopy swallowing study (VFSS) was performed in 10 patients with dysphagia after rehabilitation therapy; these patients had nasogastric tubes inserted, and a rehabilitation specialist assessed the degree of swallowing based on the patients' diet and posture. If aspiration or swallowing difficulties were observed, dysphagia rehabilitation therapy was administered. The patients were reassessed approximately 30-50 days after administration of therapy, based on the patients' condition. If aspiration is not observed, the nasogastric tube was removed. A functional dysphagia scale was used to analyze the VFSS images, and the scores were statistically calculated. The mean score of patients with nasogastric tubes was $49.79{\pm}9.431$, thereby indicating aspiration risk, whereas the group without nasogastric tubes showed a mean score of $11.20{\pm}1.932$, which indicated low risk of aspiration. These results demonstrated that a significantly low score was associated with nasogastric tube removal. Mann-Whitney's test was performed to assess the significance of both the groups, and the results were statistically significant with a P value <0.001. In conclusion, VFSS can effectively assess the movements and structural abnormalities in the oral cavity, pharynx, and esophagus. It can also be used to determine the aspiration status and ascertain the appropriate diet or swallowing posture for the patient. Therefore, VFSS can potentially be used as a reliable standard test to assess swallowing in order to determine nasogastric tube removal.

• The Journal of Korean Society for School & Community Health Education
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• v.10 no.1
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• pp.87-104
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• 2009

Objective: In this study, the dental health care knowledge, dental health behaviors and dental health status of elementary school students were compared and analyzed in the cases of their schools having dental health care center or not one. Methods: The target groups were 167 students of A school (experimental group) where pit-and-fissure sealants, fluoride mouthrinsing, and fluoride gel application were carried out with all grades of students by school dental health care center and 158 students of B school (control group) where fluoride mouthrinsing, for all grades students and pit-and-fissure sealants for the first grade students are carried out but have no the school dental health care center. Results: This study was carried out through the answer sheets and recordings of dental inspection. The findings of this study are as follows: 1. The dental health care knowledge was compared and the results showed that on average 14.2$\pm$2.1 in experimental group and 14.0$\pm$1.9 in the control group were no significantly different (p>0.05). 2. The dental health behaviors were compared and the results showed that the experimental group was significantly different(p<0.05) in terms of the number of times of dental brushing a day, the method of tooth brushing, the time of tooth brushing, the experience of tooth brushing with fluorine, the kinds of snacks and tooth brushing in school after lunch. But there was no significant difference(p>0.05) in the time of tooth brushing and the tooth brushing after eating snacks. 3. The DMF rate was compared and the results showed the significantly difference between the average experimental group and 53.8$\pm$5.0 in the control group(p<0.05). 4. The DMFT index was compared and the results showed the significantly difference between the average 0.6$\pm$2 in the experimental group and 1.4$\pm$1.6 in the control group(p<0.05). 5. The DMFI rate was compared and the results showed the significantly difference between the average 4.2$\pm$8.3 in the experimental group and 9.5$\pm$11.0 in the control group. (p<0.05). 6. The DT rate were compared and the results showed the significantly difference between the average 10.2$\pm$29.5 in the experimental group and 32.4$\pm$44.0 in the control group(p<0.05). 7. The FT rate were compared and the results showed the significantly difference between the average 88.5$\pm$31.0 in the experimental group and 67.5$\pm$44.0 in the control group(p<0.05). Conclusions: Based on the results, above there was no significant difference in dental health care knowledge between both the experimental and the control group. But we discovered that the experimental group is better than the other one in dental health care behaviors and dental health status. Therefore, we could conclude that the school dental health care center efficiently carried out the dental care and treatment. As school dental health care centers did not work out efficiently in terms of their educating on the dental health acre knowledge, the related programs to be developed and supported.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.75-81
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• 2010

By repeating nocturnal bruxism occlusal appliance's wearing condition that is used to cure temporomandibular disorders into the vitro experiment, research aims to find out how moisture infiltrated and drying cycle process affects on the surface microhardness of the resin for occlusal appliance and flexural strength. By utilizing resin for occlusal appliance which is the main component of poly methyl methacrylate, bar shaped sample was produced. For the resin sample utilized as the controlled group 1, the sample was infiltrated in the moisture for 7 days in the temperature of 37C. Then, the resin sample of the controlled group 2 was maintained in a dry condition for 7 days in the normal temperature. After that, each sample's surface microhardness and flexural strength were measured. For the resin sample that is utilized as the experimental sample, the sample was infiltrated in the moisture for 7 days in the temperature of 37C. Then, it was inundated for 8 hours a day and dried in the normal temperature for 16 hours with the continuous process of moisture infiltration and dry cycle process for 30 days. During this cycle process, sample's surface and flexural strength were measured in the 1st day, 7th day, and 30th day. Then, it was statistically analyzed to find out the difference of controlled and experiment group's surface microhardness and flexural strength. Results are 1. For the experimental and controlled group's surface microhardness of the resin for the occlusal appliance, it did not show any significant differences after moisture infiltration and dry cycle process repetition. 2. In case of the flexural strength for resin for the occlusal appliance, experimental group with moisture infiltration and dry cycle for 30 day process had greater effect than the experimental group at the 1st day and controlled group These results can be considered to be utilized from the patients of the temporomandibular disorders towards occlusal appliance used and maintained method.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.47-56
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• 2008

Risperidone is a widely prescribed atypical antipsychotic agent. Approved by the FDA as the first drug to treat irritability associated with autism in children, it is also used to treat tic disorder and Tourette's syndrome. Its adverse reactions related to dentistry include dry mouth, the mechanism of which is yet to be identified. The aim of this study is to identify, at the cellular level, how and to what extent risperidone affects intracellular free calcium concentration ($[Ca^{2+}]_i$), an primary intracellular factor in the regulation of fluid secretion in salivary gland cells. The human salivary gland cell line (HSG) was grown in MEM supplemented with 10% BCS. In order to measure $[Ca^{2+}]_i$, Fura-2/AM was loaded in the HSG, and fluorescence at 340 nm/380 nm excitation was measured in the 500 nm emission ratio. After every experiment, a calibration experiment was conducted in order to readjust the ratio to the actual $[Ca^{2+}]_i$. Changes in $[Ca^{2+}]_i$ were measured in the presence of carbachol, ATP and histamine. The researcher then explored how the pretreatment of risperidone affected such changes. Findings of this study include: 1. In HSG, $[Ca^{2+}]_i$ increased due to the addition of carbachol, ATP and histamine. The presence of risperidone inhibited the action of histamine on this process, while making little effect on that of carbachol and ATP. 2. A quantification of $[Ca^{2+}]_i$ in relation to histamine of different concentrations indicates that the effect of histamine was concentration dependent with an $EC_{50}$ of $3.3{\pm}0.5\;{\mu}M$. 3. The inhibitory effect of risperidone on histamine-induced $[Ca^{2+}]_i$ was concentration-dependent with an $IC_{50}$ of $104.4{\pm}14\;nM$. 4. Risperidone inhibits histamine-induced Ca2+ release from endoplasmic reticulum and influx of extracellular $Ca^{2+}$ in HSG cells(p<0.05).

• Journal of Life Science
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• v.20 no.2
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• pp.190-196
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• 2010

Nowadays many people use antibiotics to protect processed foods from many pathogenic bacteria. The abuse of antibiotics, however, can run the risk of creating resistant forms of bacterium. Our study focus is on making new substances that can not only replace antibiotics but also be friendly to the environment. In our experiments, we used fermented citrus fruit, soil microbes and coenzyme Q10 as probiotics and prebiotics. Chickens in the experimental group were fed these substances via oral route while those in the control group were not. After specific time periods, blood and feces samples were collected to test for Salmonella spp.. It is interesting that fermented citrus fruit was the most effective in suppressing this bacterium. Furthermore, dissection of the experiment group chickens shows that their livers did not change to a yellow color, in contrast to the control group. The results confirmed our proposal that the chickens fed with these materials can be protected from infection by Salmonella and other pathogens. These probiotics and prebiotics are highly practical because they are natural substances that can be easily recycled in the environment. It can also be used as an animal feed ingredient because of its safety.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.186-192
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• 2002

Purpose : Measurement of transmission dose is useful for in vivo dosimetry. In this study, previous algorithm for estimation of transmission dose was modified for use in cases with tissue deficit. Materials and Methods : The beam data was measured with flat solid phantom in various conditions of tissue deficit. New algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. The algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients using multiple sheets of solid phantoms. Results : The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within ${\pm}1.0\%$ in most situations and within ${\pm}3.0\%$ in experimental settings with irregular contours mimicking breast cancer treatment set-up. Conclusion : Developed algorithm could accurately reflect the effect of tissue deficit and irregularly shaped body contour on transmission dosimetry.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.274-282
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• 2000

Stainless steel crowns are widely used for restoration for primary molars. The material used for the crowns is an alloy of $70\sim80%$ nickel and $5\sim15%$ chromium. Nickel has been known to cause allergic reaction, cancer and cell toxicity. Little is known about nickel with respect to the relationship between Ni-contained SS crown and graining of Ni-resistance in oral microorganisms. The purpose of this study is to examine whether use of Ni-contained SS crown leads to occurrence of Ni-resistant microorganism, especially enterococci. The gingival crevicular fluid of two different groups was taken. Experimental group included patients wearing SS crown, and control group comprised individuals without SS crown. The samples were plated in BHI agar, BHI agar supplemented with nickel chloride at the concentration of 3mM and bile esculin azide (BEA) agar. The cultured enterococci on BEA agar medium were tested their Ni-resistance in nickel-containing media increasing concentrations from 3mM to 50mM. The results were as follows: 1. In experimental group, a total of 507,350 strains were isolated on BHI agar, of which 53,864(10.62%) strains were found to be resistant to 3mM nickel. In control group, of 414,590 isolates on BHI agar, 37,523 isolates were resistant to 3mM nickel. 2. A total of 95 enterococci were isolated on BEA agar in experimental group, while 20 were isolated in control group. of the enterococci, 68 and 12 isolates were found to be nickel-resistant in experimental and control group, respectively. 3. Of 68 nickel-resistant isolates in experimental group, one survived 50mM nickel. In contrast, none of the isolates in control group was observed to grow at the concentrations over 30mM nickel.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.361-374
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• 2009

For successful osteogenesis around the implants, interaction between implant surface and surrounding tissue is important. Biomechanical bonding and biochemical bonding are considered to influence the response of adherent cells. But the focus has shifted surface chemistry. The purpose of this study is to evaluate the MC3T3-E1 osteoblast like cell responses of magnesium (Mg) ion implanted titanium surface produced using a plasma source ion implantation method. Commercially pure titanium disc was used as substrates. The discs were prepared to produce four different surface, A: Machine turned surface, B: Mg implanted surface, C: sandblasted surface, D: sandblasted and Mg implanted surface. MC3T3 El osteoblastic like cells were cultured on the disc specimens. Cell adhesion, proliferation, differentiation, and synthesis of extracellular matrix were evaluated. The cell adhesion morphology was evaluated by SEM. RT PCR assay was used for assessment of cell adhesion, proliferation and differentiation. ALP activity was measured for cell differentiation. The results of this study were as follows: 1. SEM showed that cell on Mg ion groups was more proliferative than that of non Mg ion groups. On the machine turned surface, cell showed some degree of contact guidance in aligning with the machining grooves. 2. In RT PCR analysis, osteonectin and c-fos mRNA were more expressed on sandblasted and Mg ion implanted group. 3. ALP activity was not significantly different among all groups. Within the limitations of this study, the following conclusions were drawn: It might indicate Mg ion implanted titanium surface induce better bone response than non Mg ion groups.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.269-281
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• 2008

Fatigue or overload can result in mechanical problems of implant components. The mechanical strength in the implant system is dependent on several factors, such as screw and fixture diameters, material, and design of the fixture-abutment connection and abutment. In these factors, the last rules the strength and stability of the fixture-abutment assembly. There have been some previous reports on the mechanical strength of the fixture-abutment assembly with the compressive bending test or short-term cyclic loading test. However, it is restrictive to predict the long-term stability of the implant system with them. The purpose of this study was to evaluate the influence of the design of the fixture-abutment connection and abutment on the mechanical strength and failure mode by conducting the endurance limit test as well as the compressive bending strength test. Tests were performed according to a specified test(ISO/FDIS 14801) in 4 fixture-abutment assemblies of the Osstem implant system: an external butt joint with Cemented abutment (group BJT), an external butt joint with Safe abutment (group BJS), an internal conical joint with Solid abutment (group CJO), and an internal conical joint with ComOcta abutment (group CJT). The following conclusions were drawn within the limitation of this study. Compressive bending strengths were decreased in order of group BJS(1392.0N), group CJO(1261.8N), group BJT(1153.2N), and group CJT(1110.2N). There were no significant differences in compressive bending strengths between group BJT and group CJT(P>.05). Endurance limits were decreased in order of group CJO(600N), group CJT(453N), group BJS(360N), and group BJT(300N). 3. Compressive bending strengths were influenced by the connection and abutment design of the implant system, however endurance limits were affected more considerably by the connection design.

• Journal of Oral Medicine and Pain
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• v.26 no.4
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• pp.377-393
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• 2001

In order to study the closure stage of cranial sutures and its correlations with age, the ectocranial closure stage of coronal suture, sagittal suture, and lambdoidal suture of 67 skulls was measured. Among the skulls kept at the department of anatomy, college of medicine, Yonsei University, the ones with ages identified were used for this study. These measurements of suture closure were conducted by 4 examiners independently. The sutures were further divided by Frederic's method into 16 suture parts. The closure stages were classified by five stages of Broca-Ribbe. The following results were obtained: 1. The inter-observer reliability among 4 examiners showed high intraclass correlation coefficient of over 0.75(mean : 0.856) in all suture parts. Therefore, the determination of closure stage wasn't influenced by the subjective view of each examiner. 2. In all suture parts, the closure stage increased proportionally with age.(p<0.01) In terms of each suture part, the S2 part of sagittal suture showed the highest correlation(68.1%) while the L1-R part of lambdoidal suture showed the lowest correlation(51.3%). In addition, in terms of suture types, the correlation with age decreased in the order of sagittal suture(60.0%), coronal suture(57.7%), and lambdoidal suture (55.7%). In general, the average value of suture closure stages had 57.8% correlation with age(p<0.01). 3. The most frequent suture closure stage according to age group was '0' for ages below 30, '0' and '1' for ages within the 30's, '1' and '2' for ages within the 40's, and '2' for ages within the 50's. With older age groups, the frequency of '3' and '4' increased, and the suture closure stage increased proportionally with age. 4. The mean age by closure stage of each suture were within the 40's for the closure stage of '1', within the 50's for the closure stage of '2', and from 50's through 60's for the closure stage of '3'. The standard deviation was over 10 for all closure stages. In addition, at the same suture closure stage, the mean age according to the coronal suture was higher than the ages according to the sagittal suture or lambdoidal suture. Especially, C1-R, C1-L, C2-R, and C2-L parts showed the highest age when at the same suture closure stage. 5. The values appropriate for age estimations using suture closure stages of 16 suture parts were calculated, and a calculator for age estimation ($R^2=0.6944$, p<0.01) by ectocranial suture closure stage for Koreans is presented. From the above results, the method of using the closure stage of sutures of the skull to estimate age can be useful in individual identification of forensic science. Further extensive and accurate research using larger samples would be worthy of study.