• Restorative Dentistry and Endodontics
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• 제35권1호
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• pp.20-23
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• 2010

마우스가드는 19세기 복싱선수들의 구강내 열상과 연조직의 외상을 막기 위해 사용되었다. 최근에는 치과영역에서 다양하게 사용되고 있으며, 운동 보호 장치, 미백용 장치물, 교정용 유지 장치, 수술용 가이드 장치, 턱관절 안정 장치물 등에 쓰이고 있다. 습관적인 이 악물기에 의한 반복적인 5급 수복물의 탈락은 우선 이 악물기에 의한 스트레스를 조절한 후 수복이 이루어져야 한다. 마우스가드는 이 악물기에 의한 스트레스를 조절하는 장치물로 사용할 수 있다. 본 증례에서는 마우스가드로 치아에 가해지는 스트레스는 감소시키는 것에 대해 논의 할 것이다. 마우스가드를 사용함으로써 반복적인 탈락을 나타내는 5급 수복물의 유지에 단기적으로 만족스러운 결과를 얻을 수 있었다. 만약 환자 및 치과의사가 이 악물기로 반복적인 탈락을 나타내는 수복물로 고생하고 있다면, 마우스가드의 보조적인 사용이 치경부 수복물의 유지에 도움을 줄 수 있을 것이다.

• Restorative Dentistry and Endodontics
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• 제31권1호
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• pp.20-29
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• 2006

임상에서 5급 와동의 형태 중에 흔히 발견되는 혼합형 (교합면 쪽은 쐐기형이고 치경부 쪽은 접시형)의 와동이 형성된 상악 제 2 소구치에 170 N의 하중을 가했을 때, 수복 전 후에 나타나는 와동변연부와 와동벽, 그리고 수복물의 응력 분포를 3차원적 유한요소 분석법으로 조사한 결과 다음과 같은 결론을 얻었다. 1. 수복 전에 비해 수복 후 굽힘응력 이 집중되는 백악법랑경계와 와동저 선각부위 에서 응력이 감소하였다. 2. 수복 전에 비해 수복 후 교합면과 치경부의 와동변연과 와동벽에서는 응력이 증가하였다. 3. 혼합형 레진과 혼합형 / 흐름성 레진으로 수복하였을 때 흐름성 레진으로 수복한 경우보다 백악법랑경계와 와동저 선각부위에서 응력이 더 감소하였다. 4. 혼합형 레진과 혼합형 / 흐름성 레진으로 수복하였을때 흐름성 레진으로 수복한 경우보다 교합면과 치경부의 와동변연과 와동벽에서 응력이 더 증가하였다.

• 한국환경복원기술학회지
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• 제9권6호
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• pp.52-62
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• 2006

The flora of vascular plants around Chunji and Sochunji in Mt. Baekdu was listed 120 taxa; 31 families, 81 genera, 97 species, 1 subspecies, 21 varieties and 1 form. About endangered wild plants, 2 taxa (Paeonia obovata, Rhododendron aureum) are in class II. 12 taxa were listed as rare and endangered plants; Disporum ovale, Lilium davuricum, Saxifraga punctata, Rosa marretii, Cnidium tachiroei, Bupleurum euphorbioides, Halenia corniculata, Gentiana jamesii, Pedicularis verticillata, etc. 10 taxa were listed as Korean endemic plants; Lilium amabile, Aconitum pseudolaeve var. erectum, Oxytropis anertii for. alba, Valeriana officinalis var. latifolia, Cardamine resedifolia var. morii, Homopteryx nakaiana, Saussurea alpicola, Ligularia jamesii, etc. Specific plants by floral region were total 47 taxa; 3 taxa (Paeonia obovata, Rhododendron aureum, Pedicularis verticillata) in class V, 15 taxa (Lycopodium annotinum, Alnus maximowiczii, Saxifraga punctata, Petasites saxatile, etc.) in class IV, 5 taxa (Spiraea salicifolia, Sanguisorba hakusanensis, Acer ukurunduense, Campanula glomerata var. dahurica, Cacalia adenostyloides) in class III, 18 taxa (Lycopodium chinense, Disporum ovale, Ceologlossum viride var. bracteatum, Betula ermani, Aruncus dioicus var. kamtschaticus, Filipendula multijuga, Geranium eriostemon, Cnidium tachiroei, Ligularia stenocephala, etc.) in class II, 6 taxa (Pinus koraiensis, Cimicifuga simplex, Sanguisorba tenuifolia var. alba, Senecio nemorensis, Cacalia hastata subsp. orientalis, Cirsium pendulum) in class I. Peculiar flora around Chunji is thought to be made by the environmental factors such as wind, temperature and rainfall that influence the plants' growth.

• 한국환경복원기술학회지
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• 제16권2호
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• pp.75-92
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• 2013

The vascular plants of Thuja orientalis community in Seokmun-bong, Danyang were listed 222 taxa (4.5% of all 4,881 taxa of vascular plants); 67 families, 150 genera, 163 species, 2 subspecies, 43 varieties and 14 forms. Limestone plants, 29 taxa; Asplenium rutamuraria, Celtis koraiensis, Goodyera coreana, etc. So, Based on the legal protection species, endangered wild plants II, were recorded; Thalictrum coreanum (EN) and rare plants, 8 taxa; Thuja orientalis (LC), Exochorda serratifolia var. serratifolia (LC), Diarthron linifolium (EN), Bupleurum falcatum (VU), Lithospermum erythrorhizon (LC), Dracocephalum argunense (EN), Polygonatum robustum (EN), etc. and endemic plants, 3 taxa; Populus tomentiglandulosa (Planted plant), Thalictrum actaefolium var. brevistylum, Asperula lasiantha, etc. Based on the list of specific plants, 29 taxa; Thalictrum coreanum in class V, 7 taxa (Neillia uyekii for. uyekii, Prunus sibirica, Abelia coreana, etc.) in class IV, 8 taxa (Spiraea trichocarpa, Polygala tatarinowi, Asparagus oligoclonos, etc.) in class III, 2 taxa (Potentilla dickinsii var. dickinsii, Weigela florida) in class II, 11 taxa (Morus cathayana, Buxus microphylla var. koreana, Zizyphus jujuba var. jujuba, etc.) in class I. Based on the list of naturalized plants, 10 taxa (Robinia pseudoacacia, Oenothera biennis, Festuca arundinacea, etc.), naturalization rate (NR) was 4.5% of all 222 taxa of vascular plants and urbanization index (UI) was 3.1% of all 321 taxa of naturalized plants.

• 한국환경복원기술학회지
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• 제9권3호
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• pp.59-75
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• 2006

The vascular plants of this site was listed 360 taxa; 86 families, 229 genera, 311 species, 42 varieties and 7 forms. Specific plant species by floral region were total 40 taxa; 2 taxa(Crypsinus hastatus, Prunus yedoensis) in class V, Patrinia rupestris in class IV, 6 taxa(Elymus mollis, Carex laticeps, Poncirus trifoliata, Melia azedarach var. japonica, Koelreuteria paniculata, Crepiastrum lanceolatum) in class III, Cirsium schantarense in class II, 30 taxa(Lygodium japonicum, Pteris multifida, Phacelurus latifolius, Asparagus cochinchinensis, Ficus erecta, Machilus thunbergii, Zanthoxylum planispinum, Euphorbia esula, Mallotus japonicus, Cayratia japonica, Camellia japonica, Glehnia littoralis, Lysimachia fortunei, Messerschmidia sibirica, Ixeris repens etc.) in class I. The naturalized plants in this site were 14 families, 34 genera, 41 species, 1 varieties, 42 taxa and naturalization rate was 20.3% of all 207 taxa vascular plants. Based on the list of the rare plants by the Forest Research Institute, 2 taxa were recorded in the studied areas; Phacelurus latifolius, Crypsinus hastatus and based on the list of Korean endemic plants, 7 taxa were recorded; Populus tomentiglandulosa, Filipendula glaberrima, Prunus yedoensis, Forsythia koreana, Paulownia coreana, Weigela subsessilis, Carpinus coreana. So, wild plants disturbing ecosystem like Solanum carolinense and Ambrosia artemisiifolia var. elatior have been increasing, it needs continuing control and conservation measures on the plant ecosystem.

• 한국환경복원기술학회지
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• 제13권5호
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• pp.59-80
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• 2010

This research This research aims at developing systemic evaluation model in terms of biotope preservation through reports, literatures, and expert survey analysis by implementing biotope structure analysis in area level with selecting Hyunpoong and Yuga-myeon, Dalseong county, Daegu metropolitan city as a site. First of all, as a result of biotope type classification of research site, biotope type groups are classified into total 13, and its biotope types are divided into total 61. Also, as a result of literature analysis, total 18 items are drawn such as diversity of biotope typical species as a index item to assess the preservation value of biotope, and the first evaluation index are divided into 10 and the second ones are divided into 8 according to characteristic of index items. As a result of expert survey analysis, All 10 index items, first evaluation index, show high importance average (above 4.7). As a result of implementation of main cause for categorizing evaluation index by characteristic, there are 3 factors such as 'obstructive factor.' Based on above survey analysis result, as a result of estimating the weight of each item, 'restoration factor' showed the highest, 3.4541, but 'factor of habitat stability' showed 3.1468, which is the lowest The systemic value evaluation was set by comprehensively analyzing these results. As a result of biotope preservation value evaluation through applying research site, total 19 types which are abundant in vegetation are classified into I class, 12 types in II class, 5 types in III class, 10 types in IV class, and 15 types in V class respectively. Lastly, as a result of second evaluation, it is analyzed that there are 17 special meaningful space to preserve species and biotope(1a, 1b) and 61 meaningful space to preserve species (2a, 2b, 2c).

• 한국정밀공학회지
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• 제24권7호
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• pp.112-119
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• 2007

Cavities of Class V are caused by heavy occlusal loads due to bruxism and clenching habit. It is general to restore abfraction lesions with dental filler materials to reduce stress concentration. A material should be selected from various dental products based on long term clinical experiences or personal preference concerning filler methods. A quantitative criterion is necessary to make an evaluation of the results as dentists decide treatment methods and dental materials relying on their clinical experiences. The purpose of this study is to find an optimal restoration method and material for noncarious cervical lesions using the finite element method. An objective function was defined to minimize the sum of tensile and compressive stresses. Several models with different combinations of resins were suggested and compared in terms of the values of objective function. An optimal solution was to fill TetricFlow inside the lesion and Z100 in the remaining region with a thickness ratio of 0.125.

• Journal of Periodontal and Implant Science
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• 제39권1호
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• pp.17-26
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• 2009

Purpose: The non-carious cervical lesion(NCCL) is a loss of tooth structure at the neck of affected teeth that is unrelated to tooth caries. The reported prevalence of NCCL varies from 5% to 85%. Prevalence and severity of lesions have been found to increase with age. They are becoming more significant as people live longer and become more aware of the importance of oral health. The purposes of this study were first, to examine the periodontal conditions associated with NCCL, and second, to investigate the clinical effects of class V restorations of NCCL on periodontal tissues. Materials and methods: The sample size was 982 teeth of 50 subjects(25 male, mean age $52{\pm}7$) who were seen at the Department of Periodontology, Pusan National University Hospital. At the baseline examination, clinical periodontal parameters were measured. After the initial examination, 24 patients who were absent from hypersensitivity were selected. The teeth with NCCL were randomly divided into the test and control groups. The teeth in the test group were restored with flowable resin; the control teeth were not restored. Six months later, the clinical examinations were repeated. The data were analyzed using the SPSS program. Results: The results were as follows: 1) NCCL occurred on 45.8% of examined teeth. The percentage of affected teeth was higher in maxillary and premolar teeth. 2) The shallow saucer type was the most common. 3) Teeth with NCCL had more gingival recession, lower attachment level, and higher incidences of bleeding on probing(BOP) and plaque than NCCL-free teeth. 4) Six months later, gingival recession, attachment level, the percentages of BOP and plaque in the test group were lower than in the control group(p<0.05). Conclusion: NCCLs were more found in maxillary teeth, especially in premolar teeth. The results suggest that the restoration of NCCL could affect some periodontal parameters favorably.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.173-182
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• 1995

The purpose of this study was to evaluate the adaptability of light-cured glass ionomer cement to cavity walls. Class V cavities were prepared on the labial surfaces of extracted bovine incisor teeth. The cavities were restored with Fuji II as self-cured glass ionomer cement and Fuji II LC, Vitremer as light-cured glass ionomer cement. Fluorescent markers (fluoreceine and rhodamin B) were incorperated into liquid and primer for a better image of microscopic observation. Restored teeth were sectioned by longitudinal and labiolingual direction. The adaptability at the tooth-restoration interface was assessed incisally, axially and cervically by confocal scanning laser microscope. Following results were obtained : 1. Chemical-cured glass iomomer cement restoration showed close adaptation on the all of the cavity walls, but, cracks formed within the cement. 2. Light-cured glass ionomer cement restoration was well adapted to the cavity walls, but showed crack in the cement adjacent to axial dentinal wall. 3. There' was no significant difference in adaptability between two light-cured glass ionomer cement restorations.

• Restorative Dentistry and Endodontics
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• 제24권1호
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• pp.67-75
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• 1999

The use of composite restorative materials is established due to continuing improvements in the materials and restorative techniques. Composite resins are widely used for the restoration of cervical lesions because of esthetics, good physical properties and working time. There are several types of cavity design for class V composite resin filling, but inappropriate cavity form may affect bonding failure, microleakage and fracture during mastication. Cavity preparations for composite materials should be as conservative as possible. The extent of the preparation is usually determined by the size, shape, and location of the defect. The design of the cavity preparation to receive a composite restoration may vary depending on several factors. In this study, 5 types of class V cavity were prepared on each maxillary central incisor. The types are; 1) V-shape, 2) round(U) shape, 3) box form, 4) box form with incisal bevel and 5) box form with incisal bevel and grooves for axial line angles. After restoration, in order to observe the concentration of stress at bonding surfaces of teeth and restorations, developing a 2-dimensional finite element model of labiopalatal section in tooth, surrounding bone, periodontal ligament and gingiva, based on the measurements by Wheeler, loading force from direction of 45 degrees from lingual side near the incisal edge was applied. This study analysed Von Mises stress with SuperSap finite element analysis program(Algor Interactive System, Inc.). The results were as follows : 1. Stress concentration was prevalent at tooth-resin bonding surface of cervical side on each model. 2. In model 2 without line angle, stress was distributed evenly. 3. Preparing bevel eliminated stress concentration much or less at line angle. 4. Model with round-shape distributed stress concentration more evenly than box-type model with sharp line angle, therefore decreased possibility of fracture. 5. Adding grooves to line angles had no effect of decreasing stress concentration to the area.