• 펄프종이기술
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• 제45권1호
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• pp.75-82
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• 2013

The traditional Hanji-making was confronted with lots of industrial disadvantages and economic problems, due to the original hand-made process. Recently, the studies on the automation of overall Hanji manufacturing process is carried out by applying the commercial chemical pulping method in order to expand industrial application or efficiency of non-wood fibrous materials. However, the application of commercial pulping methods to the bast tissues of paper mulberry leads to the chemical and mechanical deterioration of cellulosic fibers. In this study, the optimal cooking method using the bast parts of paper mulberry produced by an auto-scraping device was applied to minimize the damage of fiber strength for the paper yarn manufacture. The pre-steaming treatment and alkaline pulping systems were evaluated in removal efficiency of lignin and pectin materials within the bast tissue of paper mulberry. With the application of pre-steaming treatment and 2 stage pulping system using potassium carbonate and then sodium hydroxide, kappa values were decreased two times more in lignin removal than the single stage of pulping method. It was also identified from SEM images and ATR-FTIR spectra that the pectin components within cellular structure of bast tissue were easily removed and the debarked bast parts by a auto-scraping device were easily defiberized by 2-stage pulping sequence using potassium carbonate/sodium hydroxide pulping system.

• 대한소아치과학회지
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• 제45권2호
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• pp.250-256
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• 2018

치아의 완전 탈구는 치조골에서 치아가 완전히 이탈된 것으로 정의되며, 결과적으로 신경혈관 공급의 중단을 야기하는 가장 심각한 치과적 손상 중 하나로 알려져 있다. 완전 탈구는 조직 허혈(tissue ischemia)을 야기하며, 이는 치수 괴사를 초래할 수 있다. 치근단형성술(apexification)은 치수 괴사로 진단된 미성숙 영구치에서 치근단 장벽을 유도하는 전통적인 치료 방법이다. 하지만 치근단형성술로는 치근 길이 및 두께의 증가를 포함하는 치근 발육을 얻을 수 없다. 본 증례는 완전 탈구되어 재식된 이후 치수 괴사로 진단된 치아를 가진 5세 환자에서 ciprofloxacin, metronidazole, cefaclor 및 CollaTape과 Biodentine을 이용하여 시행된 치수재생치료(regenerative endodontic treatment)의 임상적 및 방사선학적 결과를 다루고 있다.

• 대한치과보철학회지
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• 제41권2호
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• pp.111-127
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• 2003

Statement of problem : Resin cements were used widely on all ceramic crowns, but the influence of resin cements on biocells was not understood clearly. Purpose : This study was investigated to evaluate the biocompatibility of resin cements for all-ceramic crowns. Material and Method : The resin cements used in this study were Panavia F (Kuraray Co., Ltd. Japan), Variolink II (Vivadent Ets., Schann / Liechtenstein), and Bistite II (Bistite dual cure resin cement-clear Tokuyama Soda Co. Japan). The viability of normal human oral keratocytes, gingival fibroblast, and gingival fibroblast immortalized by Human Papilloma virus 16 was measured in vitro for evaluation of cytotoxicity on resin cements, and the response of pulp tissue was analyzed and evaluated with light microscope after application of cements at cutting edge of incisors. Results : The normal human oral keratocytes was the most sensitive to toxicity of resin cement, and toxicity of cements was higher in Bistite II than in Variolink II. The cell viability of immortalized gingival fibroblast did not affected by type of cement and cultivation period, but there was a tendency that cytotoxicity in Bistite II was higher than in Variolink II. The cell viability of gingival fibroblast was similar to that of immortalized gingival fibroblast regardless of cement type, but Bistite II showed more toxic than others after 5 days cultivation. The responses of pulp tissue according to cement type were similar after 2 days cultivation, but revealed high toxicity in Bistite II after 10 days cultivation. Conclusion : Variolink II was more biocompatible than any other resin cements used in this study.

• 펄프종이기술
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• 제44권4호
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• pp.51-61
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• 2012

The new alkali pulping process combined with electron beam treatment was applied to utilize hemp bast tissues as a new valuable fibrous resource. Hemp bast tissues have some chemical properties with high lignin contents and holocellulose not to be defiberized by alkali pulping only, compared with the bast tissue of paper mulberry. To make up for the weakness of traditional alkali pulping process, electron beams were directly irradiated into the swelled bast tissue of hemp in NaOH solution and distilled water, and then facilitated the defiberization of hemp bast tissues. The papermaking from hemp bast fibers manufactured by the combination pulping process showed good apparent density, formation structure and air permeability, and had some mechanical properties with lower tensile, tear, burst strength and folding endurance. It is finally concluded that the combination pulping process with electron beam treatment could be suggested a new alternative for non-woody fibers.

• Restorative Dentistry and Endodontics
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• 제47권2호
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• pp.24.1-24.15
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• 2022

Objectives: Regenerative endodontic treatment is a clinical procedure aimed at biologically regenerating damaged root canal tissue of immature permanent teeth. This study aimed to report the outcomes of regenerative endodontic treatment performed by endodontic postgraduate students. Materials and Methods: Clinical and radiographic data of 27 patients, aged 10-22 years, who underwent regenerative treatment of immature permanent teeth from 2015 to 2019 were followed up, wherein clinical and radiographic examinations were performed for each patient. Postoperative success rate and tooth survival were analyzed, and the postoperative radiographic root area changes were quantified. Results: A total of 23 patients attended the dental appointments, showing that all teeth survived and were asymptomatic. Specifically, 7 periapical pathosis cases were completely healed, 12 were incompletely healed, and 4 cases failed. Moreover, significant differences were found between discolored and non-discolored teeth, and between the presence or absence of periapical radiolucency. Additionally, 3 anterior teeth showed complete closure of the apical foramen, while the apical foramen width was reduced in 17 teeth and failed in 3 teeth. Root length was also found to have been increased in 7 anterior and 4 posterior teeth, and the average length ranged from 4.00-0.63 mm in the anterior teeth, 2.85-1.48 mm of the mesial root, and 2.73-2.16 mm of the molar teeth distal root. Furthermore, calcified tissue deposition was observed in 7 teeth. Conclusions: A favorable outcome of regenerative endodontic treatment of immature permanent teeth with necrotic pulp was achieved with a high survival rate.

• International Journal of Oral Biology
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• 제46권2호
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• pp.67-73
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• 2021

This study summarizes the recent cutting-edge approaches for dentin regeneration that still do not offer adequate solutions. Tertiary dentin is formed when odontoblasts are directly affected by various stimuli. Recent preclinical studies have reported that stimulation of the Wnt/β-catenin signaling pathway could facilitate the formation of reparative dentin and thereby aid in the structural and functional development of the tertiary dentin. A range of signaling pathways, including the Wnt/β-catenin pathway, is activated when dental tissues are damaged and the pulp is exposed. The application of small molecules for dentin regeneration has been suggested as a drug repositioning approach. This study reviews the role of Wnt signaling in tooth formation, particularly dentin formation and dentin regeneration. In addition, the application of the drug repositioning strategy to facilitate the development of new drugs for dentin regeneration has been discussed in this study.

• 대한소아치과학회지
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• 제34권3호
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• pp.506-512
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• 2007

어린이에서 치아의 외상성 손상은 흔히 일어나는 문제이며, 손상 부위 및 정도에 따라 치아의 파절, 치주조직의 손상, 지지골 조직의 손상, 연조직의 손상 등으로 분류할 수 있다. 치주조직의 손상 중 치아가 외상에 의해 함입된 경우는 상악전치부에서 흔하며, 다른 유형의 손상에 비하여 비교적 발생빈도가 낮은 편이지만, 치축방향으로 충격이 가해져 치수뿐만 아니라 지지조직까지 손상을 일으킨다. 치아의 함입에 대한 치료 방법으로는 유전치나 조금 함입된 미성숙 영구 전치의 경우, 인위적인 재위치 없이 3-4주 동안 재맹출을 기대할 수도 있으나, 심하게 함입되어 재맹출을 기대하기 어려운 영구 전치의 경우에는 교정적 견인을 통해 교합수준에 이르게 하는 것이 일반적인 방법이며, 고정성/가철성 장치를 이용할 수 있다. 이때에는 약하고 지속적인 힘을 이용하여 치아를 치관방향으로 이동시킨다. 자발적 재맹출, 교정적 견인이 불가능 한 경우에는 외과적으로 치아를 재위치 시키고 주기적으로 관찰하는 방법이 있다. 이에 외상으로 인해 상악 좌측 영구 중절치가 함입되어 내원한 8세 7개월과 9세 11개월의 환아에서, 치수 괴사에 대한 통상적인 근관치료와 고정성 장치를 이용한 교정적 견인을 통해 양호한 치료 결과를 얻었기에 보고하는 바이다.

• 대한소아치과학회지
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• 제26권1호
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• pp.157-161
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• 1999

1. Periphelal odontoma는 매우 드문 질환으로 확진을 위해서는 생검이 필수적이다. 2. Peripheral odontoma는 치은의 종창을 동반하며 서서히 성장하는 임상적 특징을 가진다. 3. 골내 치아종과 마찬가지로 peripheral odontoma의 치료로는 완전한 외과적 절제가 추천되고 예후 또한 양호하다.

• 펄프종이기술
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• 제44권6호
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• pp.58-69
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• 2012

As the meaning of dictionary terminology, scum refers to a layer of impurities that accumulates at the surface of a liquid. In papermaking process, scum indicates the floated solid waste generated by a flotation process during the primary wastewater treatment. In this study, different kinds of stocks and scums collected from newspaper, liner, tissue and fine paper were analysed in details. The purpose of this study was firstly to demonstrate the composition characteristics of different sources of scum, secondly the analysis of environmental hazardous materials, and thirdly the evaluation of reutilization ability of fibrous materials from collected scum. As mentioned the meaning of solid waste, scum was actually differ from the waste sludge in sources, compositions and recycling abilities. In the same manner of waste paper, the sludge which is generated within onsite of papermaking processes would be reused as a raw material. The general compositions of scum from waste water were mainly inorganic ash materials, fine fibre fractions, recycled fibre debries, and ink particles. If the scum is able to reuse as fibrous additives in papermaking process, it could contribute to the savings of running costs in both the subsidiaries of fibrous material and the solid waste treatment with even small quantity.

• 펄프종이기술
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• 제48권1호
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• pp.53-60
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• 2016

Abiotic-stressed tobacco stems as a non-wooden biomass were analyzed for their chemical characteristics. Light-stressed tobacco stems (LST) have a relatively high nitrogen concentration, much more extractive content, and a similar amount of lignin and higher contents of acid sugars than those of Non stressed tobacco (NST). It also has low cellulose crystallinity and a high degree of condensation. Guaiacyl units having a lower molecular weight distribution consist of rich lignin. Tension stressed tobacco (TST) growth differentiation under tensile stress was significantly different between normal tissue and cell walls, with the exception of the slightly higher cellulose crystallinity observed for.