• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.19-27
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• 2008

The purpose of this study was to obtain normative nasalance scores for adult subjects speaking the Korean language and to determine whether significantly different scores exist for female and male speakers. Mean nasalance scores were obtained for normal speaking Korean adults while they are reading vowels, consonants, no nasal sentence, mild nasal sentence, and high nasal sentence. Thirty adults who had lived in Seoul area with normal articulation, resonance, and voice were included. Among the subjects 15 were male aged 24-38 years and 15 were female aged 19-33. Nasometer data were collected and analyzed using the Kay Nasometer 6400. Nasalance scores were evaluated to investigate the effect of gender by using statistical tests. Nasalance data showed that nasalance values varied accroding to speech stimuli, and there was no significant difference in nasalance scores between male and female speakers in most of the language samples.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.1
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• pp.41-50
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• 2011

The gingival zenith is the most apical point of the gingival outline. This study aimed to quantify the mesio-distal and apico-coronal displacements of gingival zenith in maxillary anterior dentition. 50 healthy patients, who ranged in age from 25 to 36 years were recruited for the study. Alginate impressions of the study group were made and poured with the type III stone. The gingival zenith positions of maxillary anterior teeth were measured in a mesial-lateral direction from the vertical bisected midline. The apico-coronal displacements of the gingival zenith of lateral incisors were measured from a line joining the gingival zeniths of the central incisor and canine. The gingival zeniths were distally displaced in 90%, 53% and 23% of the maxillary cetral incisors, lateral incisors and canines respectively. The mean distal displacements of the gingival zeniths to the vertical bisected midline of central incisors, lateral incisors and canines were 0.90 mm, 0.29 mm and 0.06 mm respectively. The gingival zeniths of lateral incisors were positioned $0.73{\pm}0.43$ mm coronally to the line joining the gingival zenith of central incisors and canines. Consideration of these findings may improve restorative procedures in the anterior maxillary dentition.

• Journal of Korean society of Dental Hygiene
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• v.11 no.6
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• pp.923-938
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• 2011

Objectives : This study was attempted in order to grasp oral health level according to socio-demographic characteristics in elders in some communities, and to evaluate oral health status and its association. Methods : The subjects in this study were performed with 235 people, who were over 65 years and resided in Daejeon Province, from June 20 to July 10, 2011. An individual interview was held, and they got a dental checkup. As for data analysis, chi-square test, t-test, one-way ANOVA, pearson correlation were utilized. Methods : The subjects in this study were performed with 235 people, who were over 65 years and resided in Daejeon Province, from June 20 to July 10, 2011. An individual interview was held, and they got a dental checkup. As for data analysis, chi-square test, t-test, one-way ANOVA, pearson correlation were utilized. Results : The older age in the whole research subjects and the lower educational level led to the less remaining teeth and the larger missing teeth index. The decayed missing filled teeth index and the decayed missing filled teeth rate were higher in more women and older age and in the lower educational level. Tooth mortality rate was higher in the older age, the lower educational level, and the group of living together with spouse. The maxillary-mandibular fixed-bridge status in the mouth was indicated to be the highest in the full-denture mounting ratio as for elders in over 80 years old. Oral Health Impact Profile(OHIP-14) average score was $56.05{\pm}11.64$ in the whole research subjects The decayed missing filled teeth index and the decayed missing filled teeth rate showed significantly positive correlation with the decayed missing filled teeth rate, tooth mortality rate and showed significantly negative correlation with OHIP-14. Tooth mortality rate showed significantly negative correlation with OHIP-14 Oral Health Impact Profile(OHIP-14) showed significantly positive correlation with its factors. Conclusions : Accordingly, the policy effort is considered to be necessary that implements in elders in order to spend active senescence, and that elders' health and oral-health behavior can be implemented continuously and preventively through classification according to elders' physical function.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.1
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• pp.93-108
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• 2016

One of the fields to which the 3D printing technology can be applied is the field of medicine. Recently, the application of 3D printing technology to the bio-medical field has been gradually increasing with the commercializing of the bio-compatible or bio-degradable materials. The technology is currently contributing to the biomedical field by reducing times required for operations or minimizing adverse effects through preoperative identification of post-surgical consequences or model surgery with artificial bones and organs. This technology also enables the production of customized biomedical auxiliary products like hearing aids or artificial legs etc. For the field of dentistry, the 3D printing technology is also expected to elevate the level of dental treatment by making the customized orthodontic models, crown, bridge, inlay, and surgical guides for implant and surgery. However, issues remaining unidentified or incomplete in printing materials, modeling technology, software technology associated with CAD, verification of bio-stability and bio-effectiveness of materials or in compatibility and standardization of the technology are yet to be solved or be clarified for the full-scale application of the 3D printing technology, thus, it seems such issues should be resolved through further studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4329-4335
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• 2014

This study examined the effects of the shear bond strength when the surface condition of the metal and zirconia, each being the lower structures, was different when determining the bond strength (metal group) of the metal lower structure with upper ceramics, and the shear bond strength (zirconia group) of zirconia lower structure with the upper ceramics in prosthetic appliances of metal-ceramic crown and zirconia-ceramic crowns. The metal groups were divided into a total of four groups: the group with no condition on the metal surface(NM), the group with sand-blasting(SM), the group with applied opaque ceramics(OM), and the group with applied opaque ceramics and sand-blasting(SOM). The zirconia groups were also separated into four groups: the group with no condition(NZ), the group with sand-blasting(SZ), the group treated with ZirLiner on the zirconia surface(LZ), and the group applied with ZirLiner along and sand-blasting(SLZ). To examine the effects on the shear bond strength according to the surface condition of each of the four metal and zirconia groups, SPSS was used to conduct one-way ANOVA. For metal-ceramic crowns, it would be best to apply opaque ceramics after sand-blasting on the surface of the metal, the lower structure. For zirconia-ceramic crowns, it is recommended to apply the ZirLiner after sand-blasting on the surface of zirconia, the lower structure.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.142-150
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• 2013

The aim of this study was to analyze the factors related to self-reported halitosis. This study performed a questionnaire survey, targeting at 450 adults who lived in Seoul and Gyeonggi area. Main results of this study were as followings. Relationships between socio-demographic characteristics and halitosis showed no significant difference. Relationships between subjective oral health and halitosis, the groups that were treated dental prosthesis, aware of periodontal disease and dry mouth symptoms reported more halitosis (p<0.05). The group that brushed teeth less than twice a day, did not brush teeth after having a snack, and had frequent sweet treat reported more halitosis (p<0.05). The group that more experienced limitation, discomfort, discomfort reported more halitosis (p<0.05). Based on the results derived as above, the self-reported halitosis was shown to be related to periodontal disease, dry mouth, oral hygiene care and quality of life. Therefore, it is considered that preventing periodontal disease and oral dryness as well as reinforcing the oral hygiene care will contribute to prevention of halitosis and enhancement of quality of life.

• Journal of dental hygiene science
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• v.6 no.3
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• pp.153-158
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• 2006

Bleaching of vital and nonvital teeth is becoming a more commonly used treatment in the dental office and at home. To improve appearance and remove discoloration, the teeth of specific patients are treated with a variety of bleaching agents. The typical bleaching agents contains carbamide or hydrogen peroxide as the active component. The purpose of the review article was to summarize and discuss the available information concerning the effect of peroxide releasing bleaching agent on dental restorative materials and restorations. Information from all original scientific full papers or reviews listed in PubMed or ISI Web Science were included in the review. Bleaching may exert a negative influence on restorations and restorative materials. Advice is provided based on the current literature to minimize the impact of bleaching treatment on restorative materials and restorations.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.311-318
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• 2006

In an estuary, ecological dynamic is modified for a long time and memorized in soils and landscapes. As landscape memory, ecological motif is defined with dominance and rarity of vegetation. The purpose of the study is to investigate the existing vegetation character and to propose the ecological motif of this area. The present salt-water plants, community species composition and constancy degree around the estuary in Buandam watershed Buan-gun, Jeollabuk-do were analyzed. The results are as follows. The flora of the salt-water plants was listed as 16 taxa; 6 families,13 genera,14 species and 2 varieties. 5 taxa were Gramineae, 4 taxa Chenopodiaceae, and 4 taxa Comrositae. The salt-water plant communities are a total of 10 communities as listed; Zoysia sinica-Artemisia scoparia community, Phacelurus latifolius community, Artemisia scoparia Cnidium japonicum community, Limonium tetragonum -Artemisia scoparia community, Artemisia scoparia community, Suaeda japonica community, Elymus dahuricus community, Suaeda asparagoides community, Zoysia sinica community, and Zoysia sinica-Suaeda japonica community. Analyzed by the community classification species class of constancy degree, Phacelurus latifolius, Cnidium japonicum, Limonium tetragonum, Suaeda japonica, Elymus dahuricus and Suaeda asparagoides belong to I, Zoysia sinica and Artemisia scoparia to II. Elymus dahuricus, Setaria viridis var. pachystachys, Echinochloa crusgalli var. oryzicola, Phacelurus latifolius, Atriplex gmelini, Salicornia herbacea, Calystegia soldanella and Aster tripolium belong to the accompaniment species to I: Zoysia sinica, Suaeda asparagoides, Artemisia capillaris to II; Suaeda japonica, Artemisia scoparia to III ; Cnidium japonicum to IV: Limonium tetragonum, Artemisia fukudo to V. And the ecological motif is the Phacelurus latifolius community.

• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.176-181
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• 2017

PURPOSE. The purpose of this study was to evaluate the marginal and internal gaps of Ni-Cr and Co-Cr copings, fabricated using the dental ${\mu}-SLA$ system. MATERIALS AND METHODS. Ten study dies were made using a two-step silicone impression with a dental stone (type IV) from the master die of a tooth. Ni-Cr (NC group) and Co-Cr (CC group) alloy copings were designed using a dental scanner, CAD software, resin coping, and casting process. In addition, 10 Ni-Cr alloy copings were manufactured using the lost-wax technique (LW group). The marginal and internal gaps in the 3 groups were measured using a digital microscope ($160{\times}$) with the silicone replica technique, and the obtained data were analyzed using the non-parametric Kruskal-Wallis H test. Post-hoc comparisons were performed using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The mean (${\pm}$ standard deviation) values of the marginal, chamfer, axial wall, and occlusal gaps in the 3 groups were as follows: $81.5{\pm}73.8$, $98.1{\pm}76.1$, $87.1{\pm}44.8$, and $146.8{\pm}78.7{\mu}m$ in the LW group; $76.8{\pm}48.0$, $141.7{\pm}57.1$, $80.7{\pm}47.5$, and $194.69{\pm}63.8{\mu}m$ in the NC group; and $124.2{\pm}52.0$, $199.5{\pm}71.0$, $67.1{\pm}37.6$, and $244.5{\pm}58.9{\mu}m$ in the CC group. CONCLUSION. The marginal gap in the LW and NC groups were clinically acceptable. Further improvement is needed for CC group to be used clinical practice.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.4
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• pp.283-293
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• 2015

Purpose: The aims of this study are to analyze and to visualize distribution of patients visiting at a dental college hospital, using geographic information system (GIS). The visualized data can be utilized in patient care and treatment planning, ultimately leading to the assessment of risk evaluation and prevention of dental diseases. Materials and Methods: Patient information data was obtained from Dankook University Dental Hospital including the unit number, gender, date of birth, and address from 2007 to 2014. Patient distribution was visualized using GIS. Statistical analyses were performed using SAS 9.3 and ArcGIS 10.1. Five factors including proximity, accessibility, age, gender, and socioeconomic status were investigated as the explanatory variables of the patient distribution. Results: The visualized patient data showed a nationwide scale of the patient distribution. There was a little difference in characteristics for each department. As closer at Dankook University Dental Hospital, visitors increased. And it strongly showed that elderly patients in rural areas tend to visit more. Conclusion: The distribution of patients has been shown to be significantly affected by the proximity, accessibility, age, gender and socioeconomic status. The underlying reason remains to be further studied.