• 한국환경복원기술학회지
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• 제6권3호
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• pp.69-78
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• 2003

The main purpose of this study was to verify the shore margin protection effect of the root system of Salix gracilistyla Miq. developed from direct sticking cuttings on wetland, focusing on the effect of the root system reducing soil particle dissociation rate in water. The soil dissociation rate was examined through slaking tests with cylindric pure soil column at maximum particle density and the same size column of root reinforced soil. The dry weight of remained soil was measured after 5, 10, 15, 30minutes and 1, 6, 12, 24, 48hours inundation. As results, the soil particles began to dissociate severely at 10 minutes and only 10% of soil particles were left after 25minutes inundation. The stable slope angle of pure soil was $36^{\circ}$after 24 hours. On the other hand, the columns of root reinforced soil were stable even after 24hours, being dissociated only 7.2% of soil particles. So, it was revealed that the root system was very effective materials protecting more than 80% of soil particle from dissociation in inundation.

• 비파괴검사학회지
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• 제31권5호
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• pp.500-507
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• 2011

본 연구에서는 치아 시편에 AE 센서를 직접 부착하는 방법과 웨이브 가이드(waveguide)를 사용하는 방법을 이용하여 치아에 충전된 치과용 복합레진의 광중합 수축에 따른 AE 신호를 검출하여 해석하였다. PMMA, 스테인리스 스틸, 인간 치아 시편을 사용하여 AE hit와 AE 진폭(amplitude) 거동을 비교하였다. 웨이브 가이드를 사용한 경우 전파 중에 발생하는 반사파에 의한 파형의 변형으로 진폭 및 hit 수의 감소가 나타났으나, 시편의 재질에 따른 신호의 발생빈도와 1차 중심주파수의 대역은 웨이브 가이드 사용 여부에 따라 차이가 없었다.

• 식물분류학회지
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• 제49권4호
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• pp.275-281
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• 2019

One key step in the plant restoration process is the collection of seeds from the field. For the selection of source populations of target plant species for translocation purposes (reintroduction or reinforcements), several approaches are possible. A practical method involves the use of data from reciprocal transplant studies. If no direct data are available, knowledge of population genetics and the phylogeography of the target species can serve as an alternative. In this short review, we briefly propose guidelines for those collecting seeds for plant species restoration based on population genetics theory, focusing on two main questions: Where does the plant material come from and how are sources designated, and how are seeds efficiently collected from local populations? While genetic data on a larger scale (phylogeography and population genetics) are needed to form a reply to the first question, similar data on a smaller scale (fine-scale genetic structures within populations) are necessary to shed light on the second issue.

• 대한장애인치과학회지
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• 제12권2호
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• pp.66-71
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• 2016

Intellectual disability is accompanied by a high incidence of congenitally absent teeth and supernumerary teeth, and is observed more frequently than are disorders of location and order during delayed eruption, when accompanied by other symptoms. Furthermore, it is associated with a higher occurrence of dental anomalies such as conical teeth, microdontia, and amelogenesis imperfecta. As it is difficult to obtain adequate cooperation from patients with intellectual disabilities, physical restraint and conscious sedation using medication and general anesthesia can be considered. Reshaping of conical teeth with resin composite may be helpful to rehabilitate patients with oligodontia and a conical tooth shape. Diagnostic wax-up and a silicone matrix formed the basis for the successful reconstruction of the anterior teeth. This case describes the treatment of a patient with intellectual disability who had oligodontia and conical-shaped incisors. Under general anesthesia, the patient was treated using direct composite resin restoration.

• 대한심미치과학회지
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• 제17권1호
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• pp.23-30
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• 2008

Application of CAD/CAM is changing the way partial or full veneer all ceramic restoration is made. CAD/CAM systems, which were used mainly in other industries, have been developed and introduced for the dental purposes recently. It produced a flood of information on the CAD/CAM systems. It also influenced the development of restorative materials and all ceramic is substituting the traditional restorative materials of gold, composite resin and metal. Price increase of gold and other raw materials made the all ceramic more appealing. The introduction of a CEREC 3D system was innovative in several ways. Image of the prepared tooth is captured by camera and impression taking is unnecessary. Restoration can be delivered to the patient on one appointment and it will satisfy the demand of busy patients. One-day treatment with direct CAD/CAM system saves time compared to indirect CAD/CAM system. More superior restoration can be produced if lab work such as the adaptability check and shade selection is cooperated with lab technician. Short working time and comparably superior shade compatibility of color block was close to ideal. In the future, restorations with better quality can be fabricated in less time to busy patients thanks to the development of CAD/CAM system and dental materials.

• Restorative Dentistry and Endodontics
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• 제42권3호
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• pp.240-252
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• 2017

The restoration of endodontic tooth is always a challenge for the clinician, not only due to excessive loss of tooth structure but also invasion of the biological width due to large decayed lesions. In this paper, the 7 most common clinical scenarios in molars with class II lesions ever deeper were examined. This includes both the type of restoration (direct or indirect) and the management of the cavity margin, such as the need for deep margin elevation (DME) or crown lengthening. It is necessary to have the DME when the healthy tooth remnant is in the sulcus or at the epithelium level. For caries that reaches the connective tissue or the bone crest, crown lengthening is required. Endocrowns are a good treatment option in the endodontically treated tooth when the loss of structure is advanced.

• Restorative Dentistry and Endodontics
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• 제46권3호
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• pp.34.1-34.9
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• 2021

Objectives: This study aimed to assess the presence of pulp stones through an examination of cone beam computed tomography images and correlate their prevalence with age, sex, dental arch and side, tooth type, and restoration type and depth. Materials and Methods: Cone beam computed tomography images obtained from 673 patients and archival data on 11,494 teeth were evaluated. The associations of pulp stones with age, sex, dental arch and side, tooth type, and restoration type and depth were noted. All the measurements were subjected to a χ² test and one sample χ² test (p < 0.05). Results: In the study group, 163 (24.2%) patients and 379 (3.3%) teeth had at least one pulp stone. The pulp stone frequency in those aged 30-39 years was significantly greater than in those aged 18-29 and ≥ 60 years, and the frequency was higher in females than in males (p < 0.05). The highest prevalence of pulp stones was found in maxillary dental arches and molar teeth (p < 0.05). Pulp stones were significantly more common in medium-depth restorations (p < 0.05). Conclusions: Maxillary molar teeth, medium-depth restorations, individuals aged 30-39 years and females had a greater percentage of pulp stones.

• 치과방사선
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• 제8권1호
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• pp.23-27
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• 1978

The purpose of the present investigation is to determine how frequently radiopaque zones are seen on standard intraoral films and to research some other things about radiopaque zones. This study obtained the following results: 1. According to the standard intraoral films of the charts that were kept at the Dept. of Oral Diagnosis in Seoul National University Hospital, radiopaque zones were found in the rate of 4.1% among 1150 cases of amalgam-restored teeth that were treated at least two years ago. 2. Out of teeth that possessed radiopaque zones, 38.3% had radiolucent area between amalgam restoration and radiopaque zone. 3. Out of teeth that possessed radiopaque zones, 36.2% had cement base between amalgam restoration and radiopaque zone. 4. Out of teeth that possessed radiopaque zones, no tooth had periapical radiolucency. 5. Radiopaque zones were found more frequently in the mandibular teeth than the maxillary teeth. 6. According to the result of direct x-ray taking of 50 teeth that were treated at least 2 years ago, 6% had radiopaque zone.

• 한국환경복원기술학회지
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• 제2권2호
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• pp.9-23
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• 1999

Pusan's reputation as the nation's most crowded city in terms of population density is attributable to its huge mountains which allow only small portion of residential area to its large population. Rapid increase of urban population on limited amount of land had naturally led its developments efforts to mountainous area giving rise to the concern of potential landslide. This study on urban Pusan and "Landslide Hazard Map" thereof is prepared in an attempt to avoid disasters created by landslide and also as a reference for city planners. The Map shows that the area covering 38% to 43% of urban Pusan has the potential for landslide. The study also shows that various civil works involving massive land excavation had been more direct cause of landslides in Pusan than such traditional factors as locations, ground slopes, rock types and topography of the area concerned.

• 대한심미치과학회지
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• 제9권1호
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• pp.48-57
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• 2000

Direct bonded restoration with composite resin is one of the few areas which the achievement and result are available in chair side. Especially free-hand bonding technique and incremental technique give us challengeable opportunity for restoring severely damaged anterior teeth. If clinicians have keen sense of observation to evaluate polychromatic characteristics of natural teeth, hue, chroma, value, translucency, opacity and correlate the observation result with various kinds of composite resins, they will have privilege to share joy from restoring damaged anterior teeth in chair side immediately.