• The Journal of Korean Academy of Prosthodontics
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• v.39 no.1
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• pp.14-24
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• 2001

The purpose of this study was to compare the fracture strengths and the fracture patterns of several hybrid-ceramic crowns and metal-ceramic crown. Ten crowns were constructed for each group according to the manufacturer's instruction. Removable template of silicone rubber impression material was used for standardization of each crowns. Each crown was cemented on a metal die with hybrid glass ionomer cement. All crowns cemented were stored in distilled water, $36^{\circ}C$ for 24 hours prior to loading in an universal testing machine. The load was directed at 130 degrees the long axis of metal die. The fracture strengths were measured and the fracture patterns were observed. The following results were obtained from this study 1. The mean fracture strengths of $Artglass^{(R)}$, $Sculpture^{(R)}$ and $Targis^{(R)}$ were $57.5{\pm}9.5Kgf,\;62.7{\pm}12.2Kgf$ and $60.2{\pm}10.1Kgf$ respectively. There was no significant difference among each hybrid ceramic crown group. 2. The toad required to fracture hybrid-ceramic crowns was significantly smaller than metal-ceramic crowns($131.7{\pm}22.0Kgf$). 3. In the metal-ceramic crowns, labial porcelain detached partially from porcelain-metal junction of proximal side by load. 4. Hybrid-ceramic crowns showed a simple fracture pattern that fracture line began at the loading area and extended through proximal surface, perpendicular to the margin. The crown was separated into two parts of labial side and lingual side. Above results revealed that three kinds of the hybrid-ceramic crowns used in this study must have careful application in clinical use since the strength of hybrid-ceramic crown was lower(about 1/2) than that of metal-ceramic crown.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.415-421
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• 2021

The biomechanical prognosis of conventional removable partial denture is questionable in case of patient with few remaining teeth or periodontally compromised teeth. In this case, hybrid telescopic double crown RPD may be a successful treatment alternative. Hybrid telescopic double crown RPD has following advantages over conventional RPD: secondary splinting effect between abutments, more vertical stress direction and more convenient in repairing the denture after extraction of abutment tooth. In this clinical case, patient had deep overbite in anteriors and partially edentulous. The maxilla was restored with hybrid telescopic double crown RPD and the mandible was restored with implants and fixed prostheses. Long-term follow-up and supportive periodontal treatment were performed, and satisfactory results were achieved in terms of function and aesthetics.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.80-86
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• 2016

A few authors have reported good clinical results using double crown removable partial denture (RPD) with a few remaining teeth. Hybrid telescopic double crown is a good indication for a patient with poor periodontal condition and/or few remaining teeth after extraction, especially located in cross-arch position. In this case, there was a poor periodontal condition with teeth mobility. Several teeth with poor prognosis were extracted. Remaining anterior teeth was restored with fixed prostheses and edentulism was restored with Kennedy class I removable partial denture in maxilla. In mandible, it was hard to restore with clasp removable partial prostheses because of bilaterally isolated remaining teeth so that hybrid double crown removable partial denture with friction pin was suitable for this case. The objective of this report is to discuss the characteristics and the utility of hybrid double crown prostheses using a few remaining teeth in mandible.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.497-507
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• 2015

It is necessary to evaluate the resistance to disease among genetic resources for development of disease resistant grapes. This study was conducted to screen the resistance to crown gall in muscadine and Florida hybrid bunch grapes by pathogen inoculation. In order to compare the responses to infection with different pathogen strains, muscadine and Florida hybrid grapes were inoculated with 3 strains of Agrobacterium vitis. Although there were different levels crown gall formation among grape cultivars, there little variation in response to inoculated strains. Among 29 muscadine cultivars tested by inoculation of A. vitis 'C4612', most of them were shown to be susceptible, and 'Gold Isle' and 'Africa Queen' were highly susceptible, and two cultivars, 'Welder' and 'Jumbo' were found to be resistant to crown gall disease. Among Florida hybrid grapes, 'Daytona', 'Stover', and 'Swanee' were susceptible and 'Blanc du Bois' was moderately susceptible to crown gall. Because muscadine grapes have been actively utilized as useful genetic resources for development of new grape varieties by intersub-genus cross, this result from the screening of resistance among muscadine grapes can provide valuable information in breeding programs of grape resistant to crown gall.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.24-30
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• 2019

The successful results of the treatment using a double crown denture have been reported in several papers for some of the few remaining teeth in patient. In particular, double crown dentures may be an alternative to treatment in cases where the periodontal status is poor and clasp type removable partial dentures are inappropriate (crown/root ratio > 1). In this case, the patient visited clinic with a chief complaint of difficulty in mastication due to loss of posterior teeth and overall teeth mobility. After teeth with severe periodontitis were extracted, treatment plan of mandible is Kennedy class I removable partial denture (RPD) and treatment plan of maxilla is hybrid telescopic double crown RPD with a friction pin. Patient is well adapted after the prosthetic treatment and we report due to achieving satisfactory results in pronunciation, mastication, retention and aesthetics.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.73-82
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• 2004

Statment of problem : Little in known about the importance of selection of various double crowns as retainer in determining the outcome of treatment with double crown retained removable partial denture. Purpose : To obtain information about the effects and the results of this treatment modality. Material and methods : This study describes 61 double crown retained removable partial dentures worn by 51 patients from Samsung Medical Center, Seoul a time ranging between 6 and 48 months and evaluate occlusal contacts on the denture teeth, denture movement, incidence of denture relining, denture retention, fracture of dentures and abutments, hygiene, residual ridge inflammatory changes, number of lost abutment,. interruption of denture use. Results : One tenth of all the restorations were relined. Restorations in 21 arches fractured repeatedly for various reasons . There was no apparent interrelationship between fractures and the five groups. Conclusion : Good prognoses of removable partial dentures were shown in all groups(Kennedy Classes I, II, III, combination and few remaining abutment).

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.6
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• pp.677-682
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• 2006

Statement of problem. Various double crown systems have been used with removable partial dentures in the clinical field. Although retentive force between inner and outer crown are affected by several factors, differences between the retentive forces of different double crown system types are expected. Purpose. The purpose of this study was to evaluate the initial retentive force of outer crowns fabricated by the conventional casting technique in conus and hybrid double crowns. Material and methods. Ten double crowns were fabricated. The groups were as follows. Group 1, double crowns of hybrid inner and outer crowns using the conventional casting method; Group 2, double crowns of conus inner and outer crowns using the conventional casting method. Tensile strengths of double crowns when the inner and outer crowns were separated on a universal testing machine were measured. These values of retentive force were then statistically analyzed using the Kruskal-Wallis test. Results. Retentive force in group 2 was significantly higher than that in group 1(p<.05). Conclusion. The initial retentive forces of double crowns were affected by the types of the double crown system.

• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.8-13
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• 2011

This study was carried out to investigate the change of photosynthesis, leaf and fruit according to crown layers in Actinidia arguta and hybrid kiwi. Photosynthesis rate (PPFD $1,000{\mu}mol{\cdot}m^{-2}s^{-1}$) were 5.82, 7.11, $9.54{\mu}mol\;CO_2\;m^{-2}s^{-1}$ at lower, middle, and upper position, respectively in 3 layer cultivation type. The length and area of leaves collected from lower position have lager value than upper position. The fruit quality of A. arguta and hybrid kiwifruit increased with increasing crown height. A linear correlation ($R^2=0.72$, 0.89 and 0.98) was shown between fruit weight (Boeun 4, Injea 16 and HM3) and the height of crown layer(layer 1, 2, and 3). From the results, we can suppose that the tree of the upper position of crown layer in the cultivation of A. arguta and hybrid kiwifruit produce high quality fruit due to its high photosynthesis ability.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2224-2228
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• 2012

This study describes the ability of capillary electrochromatography (CEC) for the determination of imidacloprid and carbendazim in tomato samples. A novel liquid crystal crown ether modified hybrid silica monolithic column was synthesized, characterized and developed as separation column for the first time. Baseline separation of imidacloprid and carbendazim could be achieved using a mobile phase containing 90% (v/v) 20 mmol/L phosphate buffer (pH 7.0) and 10% (v/v) acetonitrile. The matrix matched calibration curves were linear with correlation coefficient $r^2$ > 0.9998 in the range of 0.20-10.00 mg/L. The limits of detection for imidacloprid and carbendazim were 0.061 and 0.15 mg/kg, respectively, which were below the maximum residue limits established by the European Union as well as Codex Alimentarius. Average recoveries for imidacloprid and carbendazim varied from 101.6-108.0% with relative standard deviations lower than 6.3%. This method was applied to the analysis of tomatoes collected from local markets.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.384-390
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• 2018

Hybrid telescopic double crown have ever been good treatment option for patient with periodontally unfavorable few remaining teeth for successful prognosis. Tooth and implant combined telescopic double crown can be used for improving retention and support for denture with strategically placed implants on edentulous ridge. In this case, an 55-year-old female patient had chronic periodontitis with few remaining teeth on maxilla and fixed partial prosthodontics on mandible. Treatment of hybrid telescopic double crown with friction pin lasted 9.5 years only with natural teeth. After 9.5 years, additional implants was installed due to fracture of cast-posted abutment teeth. After implantation, tooth and implant combined double crown had fabricated. Through re-treatment, no complications of new denture has been found during 2 years follow up. This case presents fair prognosis of tooth and implant combined double crown denture in periodontally unfavorable condition.