• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.205-216
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• 1994

The purpose of this study is to evaluate of apical plug materials for the contral of extrusion and sealing ability of high-temperature thermoplasticized gutta-percha in plastic root canal blocks. Seventy seven plastic blocks with canal preformed were instrumented with # 50K file 1 mm beyond apical foramen. Blocks were randomly divided into 5 groups of 15 blocks each. Group 1 was filled by high-temperature thermoplasticized gutta-percha only. The another 4 groups were placed with apical plug materials each other and then remaining space was back filled with high temperature thermoplasticized gutta-percha Apical plug materials were used as follows; Group 2: Thermoplasticized gutta-percha (Thermoplasticized gutta-percha group) Group 3 :. Calcium hydroxide powder (Calcium hydroxide group) Group 4 : Silver point (Silver point group) Group 5 : Gutta-percha cone softened by chloroform (Gutta-percha cone group) All the blocks were stored in 100 % relative humidor at room temperature for 14 days. Filling material extruded was removed carefully and then weighed in analytic balance. Each block was placed in centrifuge tube filled with India ink, and then centrifuged for 20 minutes at 3,000 rpm. Apical leakage was measured from the apical foramen to the most coronal level of dye leakage in millimeter by two examiners under a stereoscope. The data were analysed statistically by Student's t-test The obtained results were as follows; 1. The amounts of material extruded through the foramen decreased in all of groups used apical plug materials (P<0.01). 2. Silver point group and gutta-percha cone group were similar linear leakage to high-temperature thermoplasticised gutta-percha technique only (P>0..5). 3. Calcium hydroxide group and thermoplasticized gutta-percha group showed more liner leakage than high-temperature thermoplasticized gutta-percha only (P<0.01, P<0.05). 4. High-temperature thermoplasticized gutta-percha technique with silver point and gutta-percha cone as apical plugs showed less linear leakage and less extrusion of filling material.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.187-201
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• 1996

The purpose of this study was to evaluate the sealing ability of a calcium hydroxide plug treated with a bonding agent. Ninety extracted human anterior teeth and premolars with single canal were used in this study. Crowns were removed. the canal's were instrumented. and the roots were randomly divided into three groups of 30 each. In control group. a single apical seat was prepared with #60 K file 1mm short of the apex and the root canal was obturated with Gutta-percha and Sealapex by the lateral condensation method. In experimental group 1 and group 2. to prepare an apical isthmus of 1mm in length. the first apical seat was prepared with a #45 K file 1mm short of the anatomical apex and with a #60 K file 2mm short for the second apical seat. Dry calcium hydroxide powders were packed in the apical isthmus with a hand plugger and #60 K file and then. the root canal was obturated with Gutta-percha and Seal apex by the lateral condensation method. In experimental group 2. following an application of the bonding agent to the plug. the root canal was obturated in the same way. The teeth of each group were immersed in a 2% methylene blue dye solution. for 1, 2, and 4 weeks. The distance from the tip of the cone to the deepest penetration was measured using the Tool maker's microscope. The results were as follows : 1. The teeth having the calcium hydroxide plug treated with the dentin bonding agent (experimental group 2) showed the lowest leakage with 1.4705mm and the control group without apical plug(no apical isthmus) showed the highest leakage with 3.1735mm. 2. The control group without apical plug showed higher leakage than experimental group 1 having the calcium hydroxide plug treated without the dentin bonding agent(p>0.05). 3. The control group without apical plug and experimental group 1, having the calcium hydroxide plug treated without the dentin bonding agent. showed higher leakage than experimental group 2. having the calcium hydroxide plug treated with the dentin bonding agent(p<0.001). 4. The immersion time had no significant effect on the degree of leakage. In conclusion, the results showed that the calcium hydroxide plug treated with the dentin bonding agent could decrease the microleakage from the root apex effectively.

• Restorative Dentistry and Endodontics
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• 제34권3호
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• pp.208-214
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• 2009

이 연구의 목적은 서로 다른 두 개의 근관 크기(#70, #120)를 가진 레진 모형에 MTA (minoral trioxide aggregate)를 서로 다른 두 가지 방법 (수기구 충전(HC), 초음파 보조 수기구 충전(UAHC))으로 정방위 충전하고 MTA apical plug의 미세 누출을 평가하는 것이다. 직선형 근관 형태를 가지며, #70과 #120의 치근단 크기를 갖는 레진 모형을 각각 30개씩 준비하였다. 이 시편들을 MTA의 적용 방법에 따라 각 군을 2개의 아군으로 다음과 같이 분류하였다 (n=15); C70: HC + 치근단 크기 #70, C120: HC + 치근단 크기 #120, U70: UAHC + 치근단 크기 #70, U120: UAHC + 치근단 크기 #120. MTA 충전을 완료한 후에, 24시간 동안 실온에서 100% 습도를 유지하여 경화시켰다. 근관의 상부는 열연화 충전 시스템(Obtura II)을 이용하여 충전하였다. 48시간 동안 100% 습도를 유지하여 실온에서 0.2% rhodamine B 용액을 이용해 미세누출 실험을 하였다. 이 연구결과 #70의 치근단 크기를 갖는 그룹 사이에서 UAHC가 HC에 비해 미세누출이 적은 것으로 나타났다(p<0.05). 이 연구 조건하에서는 초음파 진동을 동반한 정방위 MTA apical plug 형성 방법이, 특히 좁은 근관에서 더 효율적인 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제39권2호
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• pp.120-125
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• 2014

Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.

• 한국작물학회지
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• 제43권4호
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• pp.223-227
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• 1998

The objectives of this study were to find the sprouting condition and to establish the optimum production methods of plug seedlings in yacon (Polymnia sonchifolia Poepp. & Endl.). The sprouting ratio was greatest at $30\pm 1^{\circ}C$ at 20 days after planting. Crowns with single buds were more effective than those with two or more buds for sprouting, which might be due to the apical dominance. Planting the shoots separated from crown after sprouting in the single- and double-layer polyethylene-covered greenhouses reduced seedling period with 25% and 50%, respectively. Planting the shoots after sprouting was more effective than planting the crown buds. Double-layer polyethylene-covered green-house was good for plug seedling production than open field or single-layer polyethylene-covered greenhouse. The bed soils composed of clay loam : compost or sand : compost (1:l=v:v) were more effective to produce plug seedlings than only clay loam, sand or compost. Seedlings could be produced at 30 days after planting in our studies.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2002년도 추계학술대회
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• pp.697-697
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• 2002

No Abstract, See Full Text

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2016년도 춘계 종합학술대회 논문집
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• pp.373-374
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• 2016

본 연구는 외상으로 인해 치수괴사가 나타난 미성숙 영구전치에서 한국에서 새롭게 개발된 MTA를 이용한 치근단형성술을 시행한 후 비교적 장기간 그 예후를 살펴본 결과를 보고하고자 한다.

• 한국유기농업학회지
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• 제8권1호
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• pp.89-99
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• 1999

To do mass multiplication of plug seedlings in potatoes, apical stem cuttings originated from virus-free microtubers were cut to one-two internodes and transplanted into the plug-tray. After 10days, we applied Chitosan and Wood Extraction on rooting and tuber formation of plug seedlings. To improve field adaptability of plug seedlings, rooted cuttings with a height of 20cm after 20days of cutting were transplanted ito the fields, We applied 500~2000ppm Chitosan on growth characteristics and tuber formation of that. The above and underground growths, such as plant height and number of leaves were significantly more vigorous after treatment with 500~1,000ppm Chitosan and 2,000ppm Wood Extraction, the spray treatment was carried out five times at intervals of four days after ten days of transplanting. T-N, K, P, Mg and Na, were higher as the concentrations of chitosan and Wood Extraction were higher. The growth and tuber yield in plug seedlings planting plot and seed potatoes planting plot were effectively highter as foliar application of Chitosan(500~2,000ppm) was done after planting the plot. T-N content in leaves and tuber was higher as the concentration of Chitosan was high. A similar tendency was shown in K, P and Mg. In the small tuber(under 30g), the number of tubers and tuber yield were relatively increased in the seed potatoes planting plot, but the large tubers(over 80g) yield was higher in the plug seedlings planting plot, and in order to increase tuber yield in plug seedlings it was necessary to add plant density to the field.

• 한국작물학회지
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• 제44권3호
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• pp.201-206
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• 1999

For the mass production of plug seedlings in cultivar ‘Dejima’ potato (Solanum tuberosum L.) the optimal apical cutting diameter for rooting and rapid multiplication of stem cuttings in hydroponics were determined. In addition, the best planting date was predicted to increase tuber yield of plug seedlings at fall cropping in Cheju-Do, Korea. Days to initial rooting decreased as the cutting diameter was reduced. Plant height, leaf number, root length and root weight per plant were favorable as the cutting diameter was small. The ideal cutting diameter was 1-2 mm in this experiment. In the hydroponic cultures, the Japanese standard (JS) nutrient solution was the most effective for multiplication of stem cuttings. It was able to propagate more than 20 times a month from a single mother plant. Viability of plants, which were derived from plug seedlings using stem cuttings, was excellent when transplanted to the field. The number of tubers and tuber yield in both of the plug seedlings and seed potato planting plots were high when planted on 25 August. The number and yield were reduced when planted on 15 August, 5 September and 15 September. The degree of decrease of tuber yield in the plug seedling planting plot however, was lower than that of seed potatoes when the planting date was late. In the case of small tubers (under 30 g), the number of tubers and tuber yield were evidently increased in the seed potato tuber planting plot; the yield of large tuber (over 80g) in the plug seedling planting plot was higher than that of the seed potato. The total tuber yield per plant in the plug seedling planting plot was less than that of the seed potato; therefore, in order to increase tuber yield it was necessary to increase field plant density.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2007년도 Autumn Scientific Meeting(the 128th) of Korean Academy of Comservative Dentistry
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• pp.607-607
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• 2007