• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.253-264
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• 1990

The purpose of this study was to estimate the distribution of absorbed doses of each important organs of head and neck region in panoramic radiography. Radiation dosimetry at internal anatomic sites and skin surfaces of phantom (RT-210 Humanoid Head & Neck Section/sup R/) was performed with lithium fluoride (TLD-100/sup R/) thermoluminescent dosimeters according to change of kilovoltage (65kVp, 75kVp and 85kVp) with 4 miliamperage and 20 second exposure time. The results obtained were as follows; Radiation absorbed doses of internal anatomic sites were presented the highest doses of 1.04 mGy, 1.065 mGy and 2.09 mGy in nasopharynx, relatively high doses of 0.525 mGy, 0.59 mGy and 1.108 mGy in deep lobe of parotid gland, 0.481 mGy, 0.68 mGy and 1.191 mGy in submandibular gland. But there were comparatively low doses of 0.172 mGy and 0.128 mGy in eyes and thyroid gland that absorbed dose was estimated at 85kVp. Radiation absorbed doses of skin surfaces were presented the highest doses of 1. 263 mGy, 1.538 mGy and 2.952 mGy in back side of first cervical vertebra and relatively high doses of 0.267 mGy, 0.401 mGy and 0.481 mGy in parotid gland. But there were comparatively low doses of 0.057 mGy, 0.068 mGy and 0.081 mGy in philtrum and 0.059 mGy in middle portion of chin that absorbed dose was estimated at 85kVp. According to increase of kilovoltage, the radiation absorbed doses were increased 1.1 times when kilovolt age changes from 65kVp to 75kVp and 1.9 times when kilovolt age changes from 75kVp to 85kVp at internal anatomic sites. According to increase of kilovoltage, the radiation absorbed doses were increased 1.3 times when kilovolt age changes from 65kVp to 75kVp and 1.6 times when kilovoltage changes from 75kVp to 85kVp at skin surfaces.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.171-177
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• 2005

This study aims to analyze effects of mothers' socioeconomic features, and knowledge and behavior of oral health on experience and purpose of using dentistry. By survey to 103 mothers of 5-6 year old children, who use day care centers in seoul, the results are obtained as follows: 1. As for the rate of experiencing dental care classified by its purpose, 56.7% for dental treatment, 23.3% for regular check-up and 20.0% for precaution 2. There was no significant difference of correlativity between mothers' socioeconomic features and knowledge of oral health and experience of using dental care, while the lower rate of using dental floss, the higher rate of experiencing dental care(p < 0.01). 3. In respect of correlativity between mother's socioeconomic features and purpose of using dental care, the purpose of regular checkup was high in a group of mothers between 33 and 35 years old(71.4%) by ages and in a group of mothers who graduated from college(57.1%) by academic background(p < 0.05). 4. In correlativity between mothers' behavior of oral health and purpose of using dental care, the result showed that the higher the rate of using dental floss was, the higher the rate of experiencing dental care for a regular check-up was(p < 0.001) and the higher the rate of using fluoride dentifrices was, the higher the rate of using dental care for cure was(p < 0.05). 5. Multiple regression based on dependent variable of experience in using dental care showed that average monthly income(less than 2,500,000 won) was significant explanatory factor with 65% of explanatory variance. On the other hand, multiple regression based on dependent variable of purpose of using dental care showed that vocation(professional job) and age(between 33 and 35 years old) was significant explanatory factor with 70% of explanatory variance for a regular check-up, age(between 33 and 35 years old) and average monthly income (less than 2,500,000 won) was significant factor with 78% of explanatory variance for precaution and age(less than 32 years old) was significant explanatory factor with 33% of explanatory variance for treatment.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.448-454
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• 2014

The aim of this study was to evaluate the effect of a water fluoridation program (WFP) on prevention of dental caries in Gimhae City, Korea, with reference to the results of 2012 Korean National Oral Health Survey (KNOHS). In WFP population, 972 subjects including 8-, 10- and 12-year-old children in Gimhae City were examined in 2009. The WFP in Gimhae city has been implemented since 1999. 1872 subjects in non-fluoridated small and medium sized cities similar to Gimhae city were selected from 2012 KNOHS data as the control population. Two dentists who received training in KNOHS with an inter-examiner-agreement examined oral health status of all subjects. To assess the effects of WFP on dental caries, caries preventive fraction was estimated by assessing the differences of decayed, missing, and filled teeth (DMFT) index and decayed, missing, and filled surfaces (DMFS) index, DMFS in pit and fissures and smooth surfaces between WFP population and the control. Univariate analysis of variance adjusted for gender and number of fissure-sealed teeth or surfaces was conducted. DMFT of 12-year-old subjects (n=354) in WFP and control population (n=1,518) were 1.60 and 2.12, respectively, with an estimated prevention effect of 24.7%. Caries preventive fraction on pit and fissure, and smooth surfaces of WFP subjects was estimated 27.5% and 24.0%, among subjects aged 12 years, respectively. WFP in Gimhae City, Korea reduced the prevalence of dental caries and is recommended as a public oral health program where a fluoride-containing toothpastes are commonly used.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1380-1387
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• 2014

The purpose of this study was to develop a mouthwash product with solid fermented oriental medicinal herb (OMH). Solid fermentation of magnolia, liquorice, and cnidium by Phellinus linteus mycelium was carried out successfully when 30% water was added to the medium, whereas 10% brown rice powder was required as an extra nutrient for solid fermentation of mint besides water. The amount of total phenol compounds and DPPH radical scavenging activity of OMH increased significantly (P<0.05) upon solid fermentation. Anti-microbial activities of fermented OMH also increased and were approximately 100-fold greater than those of unfermented samples. Oral pathogens such as Staphylococcus epidermis, Streptococcus pyogenes, Candida albicans, or Streptococcus mutans were used for determination of anti-microbial effects of OMH. Formulation of the mouthwash was developed based on the results of the sensory evaluation. Among seven formulas, the best formula chosen by the sensory evaluation was as follows: mouthwash prepared with 0.075% ethanol extract of solid fermented OMH as a main ingredient, 83.64% hot water extract of mint and clove (100:15, v/v) as a mouthwash base component, and other miscellaneous ingredients, including sodium fluoride, menthol, and surfactants. Data from a consumer's preference test with 30 participants, overall acceptance, and willingness to buy the product developed in this study were all significantly higher for the tested mouthwash compared to mouthwash on the market manufactured with OMH but with a different formula. Duration of freshness of the mouthwash after usage as determined by Breath Checker was not significantly different between the two samples, although the duration of our product was slightly longer than that of the commercial product mentioned above.

• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.235-245
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• 1995

The purpose of this paper is to review two recently reported, long-term studies of several chemical methods to control gingivitis and decalcification in adolescent orthodontic patients. The first study(gingivitis study) was designed to determine whether conventional toothbrushing and twice daily use of a brush-on 0.4 per cent $SnF_2$ gel containing more than 90 per cent available $Sn^{2+}$ would be more effective for controlling plaque accumulation and gingivitis in the presence of orthodontic appliances than conventional toothbrushing alone. The second study(decalcification study) was designed to compare the effectiveness of controlling decalcification in orthodontic patients with either a II00 ppm F tooth paste used alone, this same toothpaste and a 0.05 percent NaF rinse or this toothpaste and a 0.4 percent $SnF_2$ gel. In the gingivitis study, sixty-five consecutively treated adolescents who were to receive full-mouth fixed orthodontic appliances were assigned to two groups according to age and sex criteria. In the decalcification study an additional 30 subjects(95 total) were similarly assigned to a third group. The first group(control, n=35) used only toothbrushing with a standard fluoride(1100 ppm F) toothpaste. The second group used toothbrushing with a similar dentifrice supplemented with a 0.4 percent $SnF_2$ gel($SnF_2$ gel group, n=30) used twice daily for the entire 18-month study period. The third group(in the decalcification study only) used a similar toothpaste and 0.05 percent NaF rinse(NgF rinse group, n=30). Clinical assessments of plaque accumulation using the Plaque Index, gingival inflammation using the Gingival Index, and coronal staining were completed single-blinded before appliances were placed and 1, 3, 6, 9, 12 and 18 months after appliances were placed. Decalcification was assessed single blind on all labial surfaces of all erupted teeth before appliances were placed and 3 months after appliances were removed. The results of the gingivitis study indicated that the $SnF_2$ gel gorup had significantly lower scores for the Plaque Index(p<0.01) and Gingival Index(p<0.001) at all examinations during orthodontic treatment than did the control group. In the $SnF_2$ gel group, one subject developed mild coronal staining and two subjects developed moderate staining. In the decalcification study, when pre-treatment levels of decalcification were subtracted from post-treatment values, significantly lower decalcification scores(p<0.05) were found for both whole mouth and first molars in the NaF rinse and gel groups as compared with the control gorup(toothpaste alone). Although the gel group consistently had less decalcification than the rinse group, this difference only approached statistical significance.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.653-660
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• 2006

Fuji VII is a glass-ionomer cement specially targeted for early protection in erupting first and second molars. Properties of Fuji VII such as very high level of fluoride release, low viscosity and no need to preliminarily etch the substrate would be useful to erupting molars with primary pit and fissure caries or hypoplastic area for preventive goal or remineralization. The purpose of this study were to evaluate remineralization of Fuji VII glass ionomer cement and to compare with one of other restorative materials such as conventional glass ionomer cement, resin-modified glass ionomer cement, compomer and composite resin. Forty-two extracted human molars were used for this study. All teeth were immersed in demineralizing solution for 48 hours after Class V cavity preparation was made on sound proximal surface. The teeth were randomly divided into six groups and restored with Fuji VII, Fuji II, Fuji II LC improved, F2000, $Filtek^{TM}$ Z250 and control group was unrestored. The middle area with $130{\pm}20{\mu}m$ thickness was separated from specimen using microtome and demineralized area was photographed under polarized microscope. Separated area was relocated to specimen and stored in artificial saliva, After four weeks, changes of demineralized area were observed and compared to them restorated immediately. The results from the this study can be summarized as follows ; 1. Fuji VII, Fuji II, Fuji II LC improved have more prominent remineralization effect than F2000, $Filtek^{TM}$ Z250, control group. 2. No significant differences in remineralization effect are seen between Fuji VII and Fuji II, Fuji II LC improved.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.225-238
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• 1989

These studies were conducted to investigate the extraction, purification and characterization of oriental pear (Niitaka. Pyrus pyrifolia Nak.) protease, and the results obtained were as follows: 1. Oriental pear protease was effectively extracted by the method of homogenizing pear pulp with 0.7 volume of 0.1M-sodium phosphate buffer, pH 6.5 containing 5mM-cysteine, 40mM-2-mercaptoethanol and 2mM-EDTA at 10,000 rpm for 5 min. 2. The protease was purified by ammonium sulfate fractionation, Sephadex G-100 filtration and DEAE-Sephadex A-50 column chromatography, and the purified enzyme gave a single protein band on polyacrylamide gel electrophoresis. 3. The specific activity of purified enzyme was 29.65 unit/mg protein and the yield was 7.22%. 4. The moecular weight of the protease was estimated to be about 51,000 by SDS-polyacrylamide gel electrophoresis, and the enzyme had Km value of 54.5 mg/ml for casein. 5. The purified enzyme had a maximum activity at pH 6.0 and $50^{\circ}C$, and was stable from pH 5.5-6.5 and at temperatures below $50^{\circ}C$ 6. Casein was a better substrate for this protease compared to hemoglobin. 7. The enzyme activity was markedly inhibited by p-chloromercuribenzoic acid and heavy metal salts such as $HgCl_2$ and $MnSO_4$ also considerably inhibited the enzyme activity.

• Journal of Korean society of Dental Hygiene
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• v.7 no.1
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• pp.91-103
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• 2007

The purpose of this study was to pave the way for the development of oral health promotion programs for children from the low-income class. The subjects in this study were 322 children from the city of Incheon. Some of them visited local childcare centers, and the others attended six different adjacent elementary schools. Their awareness of oral health, oral health behavior and preventive-treatment experience were investigated in May 2005, and whether there were any characteristics in their visit of dental institutions was checked. Besides, whether their parents advised them to brush their teeth before turning in was examined. The findings of the study were as follows: 1. 22.0 percent of the children investigated were visiting local childcare centers, and 78.0 percent weren't. The guardians of the former group largely received high-school(50.7%) and middle-school or lower education(22.5%), and those of the latter group mostly received high-school(41.0%) and college- or higher education(35.5%)(pE0.001). The common monthly mean house-hold income of the former was one million won or less(54.9%) or ranged from 1.01 to 2.00 million won(19.7%), and the most prevalent monthly mean household income of the latter was between 2.01 and 3.50 million won(28.7%). The second most dominant monthly mean household income of the latter ranged from 1.01 to 2.00 million won(28.3%), and the third most common one was 3.50 million won or more(12.0%)(pE0.001). 2. The most prevalent daily toothbrushing frequency among the local childcare center visitors was twice(39.4%), followed by three times(19.7%). The third largest group of the visitors brushed their teeth after each meal(19.7%). The most dominant daily toothbrushing frequency among the non-users of local child care centers was twice(54.2%), followed by three times(29.1%)(pE0.01). As to the way of toothbrushing, 58.2 percent of the visitors and 74.9 percent of the non-visitors brushed their teeth by turning their toothbrush or up and down(pF0.05). 62.0 percent of the former and 74.9 percent of the latter always brushed their teeth before turning in, and whether they visited local childcare centers made a significant difference to that(pE0.05). 3. 69.7 percent of the non-visitors were always advised by their parents to do toothbrushing before turning in, and the visitors who were given the same advice all the time numbered 29.6 percent(pE0.001). 4. 56.4 percent of the visitors and 72.1 percent of the non-visitors had ever visited dental institutions over the past year. Dental hospitals and clinics were identified as the dental institutions that they visited the most, and they mostly received dental-caries treatment or had a tooth out there. 49.3 percent of the visitors and 35.1 percent of the non-visitors had ever had a toothache. 5. Sealant was experienced by 42.3 percent of the visitors and 46.2 percent of the non-visitors to prevent dental caries(pF0.05). 33.8 percent of the visitors underwent fluoride application, and that rate was higher than that of the non-visitors with the same experience that stood at 22.7 percent(pE0.05). The visitors mainly acquired knowledge on oral health through other channels that weren't specified in the questionnaire(28.2%), and the non-visitors did it mostly at dental clinics(39.0%)(pE0.001).

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.569-577
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• 2007

The purpose of the present study was to propose some amendments on nutrient standard regulations of infant formula in Korea. For this purpose, we compared and analyzed the nutrient regulations of Korea, CODEX, U.S.A, Japan, EU, Australia and New Zealand. Some developing aspects of Korea's nutrient standard regulations for infant formula need to be examined as follows: firstly, both milk-based formula and soy-based formula standards would be unified into an infant formula, and the user of infant formula would be categorized for babies less than 6 month old. Secondly, nitrogen conversion factor of milk protein in the infant formula would be 6.38, which is the same as that of CODEX Revised Standard. Protein quantities could be differentiated by protein sources, and essential amino acids in human milk would be standardized according to protein contents. Thirdly, $\alpha$-linolenic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) as essential fatty acids and trans fatty acid would be standardized in terms of the contents. Fourthly, it is recommended that the unit of vitamins and minerals would be changed from g/100 g to g/100 kcal, and individual vitamins and mineral would have their maximum values. Finally, 5 nucleotides (cytidine, uridine, adenosine, guanosine, inosine 5'-monophosphate) and fluoride would be required for the strengthening the immunity and the development of teeth, respectively. In conclusion, the scientific studies on amendment scheme of nutrient standard regulations of infant formula is very important to fortify nutritional completeness for Korean infants and young children.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.715-721
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• 2007

Residual calcium concentration is high, in general, at the effluent of the fluoride removal process in the electronics industry manufacturing semiconductor and LCD. To increase the stability of the membrane process incorporated for reuse of wastewater, the residual calcium is required to be pre-removed. Hyperkinetic Vortex Crystallization(HVC) process was installed in the electronics industry manufecturing semi conductor as a pilot scale for accelerating calcification of calcium ion. Compared to the conventional soda ash method, the 31% higher calcium removal efficiency was achieved when HVC was applied at the same sodium carbonate dosage. In order to maintain the economic calcium removal target of 70% preset by manufacturer, the dosing concentration of the soda ash was 530 mg/L based on influent flowrate. The seed concentration in the reactor was one of the critical factors and should be maintained in the range of $800\sim1,200mg$ SS/L to maximize the calcium removal efficiency. The calcite production rate was 0.30 g SS/g $Na_2CO_3$ in the average. The economic HVC passing time of the mixture was in the range of $2\sim5$ times. Relatively, stable calcium concentration was maintained in the range of $30\sim72$ mg/L(average 49 mg/L) although the calcium concentration in the feed was severely fluctuated with $74\sim359$ mg/L(average 173 mg/L). The HVC process was characterized as environment-friendly technology reducing chemical dosage and chemical sludge production and minimizing maintenance cost.