• Journal of dental hygiene science
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• v.15 no.6
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• pp.815-824
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• 2015

This study aims to figure out the current state of health insurance education provided to dentists and personnel in charge of insurance claim as well as the effects of experiences in education on their knowledge of health insurance standard and actual application. As a result of analysis on 100 data sheets related to dentistry and 100 data sheets related to personnel in charge of insurance claim (a total of 200 data sheets), following results were generated. Insurance claim personnels showed higher score than dentist in knowledge of health insurance standard and it was significant statistically. Knowledge of insurance claim personnel showed significant differences in educational experiences, in health insurance for the latest three years and average hours of education per session whereas that of dentists did not indicate any significant differences. The level of practical application of dentists was significantly different (p<0.05) according to experiences in insurance claim, and that of insurance claim personnel significantly varied (p<0.05) depending on age, experiences of insurance education and average hours of education. The longer average hours of education, the higher level of practical application. Experiences of insurance education turned out to affect on the knowledge of health insurance standard significantly (p<0.05) on the part of dentists and insurance claim personnel, and the level of experiences in insurance claim and knowledge of health insurance standard on the part of dentists and insurance claim personnel turned out to affect on practical application significantly (p<0.001). Judging from the result, continuous education needs to be conducted in order to enable dentists and insurance claim personnel to maintain the level of knowledge about health insurance and practical application.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.308-317
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• 2015

This study attempted to identify the possibility of natural herbal extracts as an alternative, preventive agent of caries by comparing antimicrobial activities between natural herbal extracts and mouth rinsing solutions against Streptococcus mutans. Natural herbal plants were extracted with distilled water and ethanol, respectively, to measure the minimum growth inhibitory concentration of S. mutans depending on concentration, and among which, solvents showing high antimicrobial activity were selected to compare their antibiotic effects with those of mouth rinsing solutions. Also, to determine the concentration of natural medicinal herbs that can be used safely in the oral cavity, the extracts were treated to the normal gingival fibroblast cells depending on concentration in order to determine its cytotoxicity using MTT. In terms of the minimum growth inhibition concentration, the growth inhibition of S. mutans was more excellent in the ethanol extract than in the distilled water. When the minimum growth inhibition concentration was compared, Psoralea corylifolia of natural herbal ethanol extracts, and Hexamedine (Bukwang Pharm., Korea) of mouth rinsing solutions inhibited growth of S. mutans at the lowest concentration. When the minimum bactericidal concentration was compared, P. corylifolia of natural herbal extracts, and Hexamedine and Garglin (Dong-A Pharm., Korea) of mouth rinsing solutions eliminated S. mutans at a low concentration. The human gingival fibroblast was treated with natural herbal ethanol extracts at the minimum growth inhibition concentration of 10, 39, and $78{\mu}g/ml$. As the result, no cytotoxicity was found. When this was treated at different minimum bactericidal concentrations, natural herbal ethanol extracts showed cytotoxicity except P. corylifolia.

• Journal of dental hygiene science
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• v.16 no.5
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• pp.393-399
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• 2016

The objective of this study was to realize research demands by gathering the research agenda from the Korean Dental Hygienists Association and affiliated groups through a Delphi survey. The study subjects were the heads of eight groups. The Delphi survey was conducted by e-mail after a researcher explained the objective of the study to the heads. The research agenda was classified according to the Korean dental hygiene academic classification and the National Dental Hygiene Research Agenda classification. To compare the number of research agendas according to classification among the groups, we conducted a chi-squared test by using IBM SPSS 20.0. In total, 316 agendas were submitted. According to the Korean dental hygiene academic classification, there was a significant difference among the groups, and the agendas associated with clinical dental hygiene (36.7%) were the best. According to the National Dental Hygiene Research Agenda classification, there was no significant difference and the agendas associated with health promotion and disease prevention (27.8%) were the best. In conclusion, the Korean Dental Hygienists Association and affiliated groups demanded similar research agendas, corresponding to the purpose of each establishment. However, the groups did not seem to show unique characteristics according to the purpose of each establishment. In other words, the groups should corroborate such characteristics and suggest a corresponding agenda to establish specific areas of research in dental hygiene. Also, dental hygiene researchers should mark the academic classification of the studies they want to submit.

• Journal of Life Science
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• v.19 no.8
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• pp.1152-1158
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• 2009

For the toxicological pathologic study of amanita muscaria, we have investigated single and repeated dose toxicity in Sprague-Dawley (SD) rats. Single dose toxicity study was identified as catalepsy, incline and tail pinch methods (control 0 mg/kg, low 3.3 mg/kg, middle 16.5 mg/kg, high 33.0 mg/kg). Repeated dose toxicity study was carried out in blood tests, serum tests and histopathological methods. Neurotoxicity - muscle paralysis, and convulsion and loss of movement - was observed at 33.0 mg/kg group in the single dose toxicity study. Dysfunction of liver and kidney were shown in the repeated oral administration of the amanita muscaria at 3${\sim}$4 weeks. Serum chemistry results revealed a marked increase of LDH [Lactate Dehydrogenase (3181.5 IU/L; normal 230-460 IU/l)], ALT [Alanine transaminase (124.0 IU/l; normal <40 IU/l)] but the kidney was normal. Histopathological results show interstitial edema and tubular epithelial necrosis in the kidney. These results suggest that amanita muscaria has a neurotoxic effect and causes dysfunction of liver and kidney in the SD rat.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.27-41
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• 1999

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-30Pd-10Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at 350-$550^{\circ}C$ Age-hardening characteristic of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, energy dispersed spectra and electron probe microanalysis. Principal results are as follows ; Maximum hardening occured in two co-phases of ${\alpha}_2$ + PdCu In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase($L1_o$ type) and an Ag-rich ${\alpha}_2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu redered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}{\to}{\alpha}_1+PdCu{\to}{\alpha}_2+PdCu$ at Pd/Cu = 3 Pd element of Ag-Pd-Cu alloy is more effective dental alloy on anti-corrosion and is suitable to isothermal ageing at $450^{\circ}C$.

• Journal of Technologic Dentistry
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• v.19 no.1
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• pp.21-35
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• 1997

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy is cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-20Pd-20Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electic furace and centrifugal casting machine in Ar atmoshpere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age-hardening characteristics of the small Au-containing Ag-pPd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, emergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, I. e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the Llo type face centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affedted by the Cu concentration. In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase(L1o type) and an Agrich ${\alpha}2$ phase occurred and a discontiunous precipitation occurred at the grain boundary. Form the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}\to{\alpha}+{\alpha}2+PdCu\to{\alpha}1+{\alpha}2+PdCu$ at Pd/Cu = 1 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.93-102
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• 2011

Purpose: The study aimed to evaluate working environment for dental technician by measuring dust level, ventilation conditions and the use of personal protective equipment and to provide basic information required to improve working environment and develop health education programs for dental technician. Methods: A total of 240 dental technician who are registered with the Daegu Association of Dental technician and working at 34 dental laboratories participated in the study. And the dust level was measured at 21 different spots in 16 dental laboratories out of 34. Results: Of 34 dental laboratories, 31 (91.2%) were equipped with a ventilator, but the remaining 3 (8.8%) did not have a ventilator. By the number of ventilator, 1 to 3 ventilators were found in 22 dental laboratories (71.0%), 4 to 6 ventilators were in 7 laboratories (22.5%) and more than 7 ventilators in 2 laboratories(6.5%). According to the frequence of changing filters in dust collector, 20 dental laboratories (58.9%) changed filters every four weeks, 10 laboratories (29.4%) changed them every six weeks and 4 laboratories (11.7%) changed them every eight weeks. Of total respondents, 114 (61.3%) said they wore a mask all the time while working, 56 (29.6%) said they frequently wore a mask, 19 (10.1%) said they did not wear a mask. As for the type of masks, 159 (84.1%) used a disposable mask, 25 (13.2%) used a cotton mask and 5 (2.7%) used an anti-dust mask. For dust sat on their outfits while working, 102 (54.0%) shook their uniforms inside workplace to keep dust off the uniforms, 64 (33.9%) did not anything until they wash their uniforms and 23 (12.1%) shook their uniforms outside workplace to keep dust off the uniforms. Of total respondents, 182 (96.3%) had a particle in their eyes while carrying out grinding work. Based on the measurement of floating dust at workplace, 3 dental laboratories showed dust concentration exceeding the minimum level of 10 mg/$m^3$ allowed under the permit for environment. Of those, 1 laboratory had the dust concentration that was more than 1.5 times higher than the minimum level. Dust concentration was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Dust comprised of nickel (more than 70%), chrome (9%) and others. The mean chrome concentration was more than twice higher than the minimum permissible level of 0.5 mg/$m^3$. There were two laboratories that showed chrome concentration exceeding the level of 0.4 mg/$m^3$. Like dust concentration, chrome level was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. There were six laboratories that had nickel concentration exceeding the minimum permissible level of 1 mg/$m^3$. Of those, one laboratory had nickel concentration that was more than three times higher than the minimum permissible level. Nickel concentration was also higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Conclusion: It is not likely that heavy metal concentrations found in the study constitute respiratory dust. It is however necessary for health of dental technician to apply the Industrial Safety and Healthy Law to dental laboratories and make recommendations for the use of personal protective equipment, installation of a proper number of ventilators, more frequent change of filters in dust collector and improved ventilation for polishing work. At the same time, dental technician need education on how to use personal protective equipment and how to efficiently remove dust from their uniforms.

• The korean journal of orthodontics
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• v.32 no.1 s.90
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• pp.19-31
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• 2002

To investigate the association between the hypertrophy of adenoid and jaw morphology during growth, this paper was based on children patients with experimental adenoids (male-15 subjects at each bone age group, female-15 subjects at each bone group) and comparing them to data taken from a control group (male-15 subjects at each bone age group, female-15 subjects at each bone group) with normal respiratory function. The comparisons between the groups were done at each growth stage using cervical vertebrae maturation index(CVMI) of Hassel. The obtained results were as follows : 1. The differences in craniofacial morphology between experimental group and control group were appeared from CVMI 3 and CVMI 4 (aroud adolescent period) in males, and from CVMI 1 in females. 2. The mandibular position of experimental group was more inferior than control group. The difference appeared at adolescent period(male : at CVMI 4, female : at CVMI 5). 3. Experimental group had greater anterior facial height than control group. This difference seemed a relation with lower anterior facial height. The difference appears at CVMI 3(11.94 ${\pm}$ 1.38 years old, at adolescent period) in male and at CVMI 1 in female. 4. The adenoid size of control male group was increased until CVMI 2(10.58 ${\pm}$ 1.07 years old, just before adolescent growth peak) and then decreased, but in female the adenoid size was decreased from CVMI 1(6.92 ${\pm}$ 0.53 years old).

• The korean journal of orthodontics
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• v.36 no.6
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• pp.412-421
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• 2006

Objective: The result of finite element analysis depends on material properties, structural expression, density of element, and boundar or loading conditions. To represent proper elastic behavior, a finite element model was made using Hounsfield unit (HU) values in CT images. Methods: A 13 year 6 month old male was used as the subject. A 3 dimensional visualizing program, Mimics, was used to build a 3D object from the DICOM file which was acquired from the CT images. Model 1 was established by giving 24 material properties according to HU. Model 2 was constructed by the conventional method which provides 2 material properties. Protraction force of 500g was applied at a 45 degree downward angle from Frankfort horizontal (FH) plane. Results: Model 1 showed a more flexible response on the first premolar region which had more forward and downward movement of the maxillary anterior segment. Maxilla was bent on the sagittal plane and frontal plane. Model 2 revealed less movement in all directions. It moved downward on the anterior part and upward on the posterior part, which is clockwise rotation of the maxilla. Conclusion: These results signify that different outcomes of finite element analysis can occur according to the given material properties and it is recommended to use HU values for more accurate results.

• Journal of dental hygiene science
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• v.6 no.1
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• pp.1-9
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• 2006

Cathepsin K (cat K) is the major cysteine protease expressed in osteoclasts and was thought to play a key role in matrix degradation during bone resorption. It was shown that the intracellular maturation of cat K was prevented by the cAMP antagonist, Rp-cAMP, and the protein kinase A (PKA) inhibitors of KT5720 and H89. In contrast, forskolin, a adenylate cyclase agonist, rather induced Cat K processing and maturation in osteoclasts. Furthermore, to determine whether cat K processing and maturation signaling involves protein kinase C (PKC), mouse total bone cells were treated with calphostin C, a specific inhibitor of PKC, however, no effect was observed, indicating that calphostin C did not affect to osteoclast-mediated cat K processing and maturation. Thus, it is indicated that the cAMP-PKA signaling pathway regulates cat K maturation in osteoclasts. Since secreted proenzymes have the potential to reenter the cell via M6P receptor, to prevent this possibility, it was tested cAMP antagonist Rp-cAMP and the PKA inhibitors KT5720 and H89 in the absence or presence of M6P. Inhibition of cat K processing by Rp-cAMP, KT5720, or H89 was observed in a dose-dependent manner. Furthermore, the addition of M6P resulted in enhanced potency of Rp-cAMP, KT5720 and H89. These dose-dependently inhibited in vitro bone resorption with a potency similar to that observed for inhibition of cat K processing.