• Restorative Dentistry and Endodontics
• /
• 제43권1호
• /
• pp.11.1-11.10
• /
• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• 구강회복응용과학지
• /
• 제33권2호
• /
• pp.106-113
• /
• 2017

목적: 근관 세정제로서 Hydroxyethylidene bisphosphonate (HEBP)가 다른 근관 세정제인 Sodium hypochlorite (NaOCl), Etylenediaminetetraacetic acid (EDTA) 상호 작용 시 조직용해 능력, 항균효과와 온도에 따른 조직 용해 능력의 변화에 대해 알아보았다. 연구 재료 및 방법: 소의 근육으로 제작된 동일한 단면적($2{\times}2{\times}2mm$)을 가진 80개의 시편을 8개의 그룹(n = 10)으로 임의로 나누었다. 초기 무게 측정 후 각각의 제조된 근관 세정제에 넣어 5분, 10분, 15분 후 무게를 측정하여 무게변화율을 구하였다. 항균 효과 조사를 위해 Enterococcus faecalis를 접종한 agar diffusion test를 시행하였다. 결과: 조직 용해 능력은 NaOCl group (G4, 5)이 가장 뛰어났으며, NaOCl과 HEBP의 혼합물(G7, 8)이 다음으로 나타났다. 또한 가열된($40^{\circ}C$) NaOCl과 NaOCl/HEBP의 혼합물의 경우 실온($25^{\circ}C$)보다 우수한 조직용해 능력이 나타났다. 항균 효과의 경우 EDTA > EDTA + 1% NaOCl > $1%\;NaOCl{\geq}1%\;NaOCl$ + HEBP 순으로 나타났다. 결론: HEBP는 NaOCl 의 항균 효과를 방해하지 않으며, 조직 용해 능력에도 기존의 킬레이팅 제재에 비해 적은 영향을 미친다. 가열된 NaOCl, NaOCl과 HEBP의 혼합재제는 실온과 비교 시에 효율적으로 조직을 용해할 수 있다.

• 한국표면공학회지
• /
• 제46권3호
• /
• pp.105-110
• /
• 2013

ZnS thin films were prepared on glass substrate by using chemical bath deposition method. The influence of ammonia ($NH_4OH$) and $Na_2EDTA$ ($Na_2C_{10}H_{16}N_2O_8$) as complexing agents on structural and optical properties of ZnS thin films were investigated. Zinc acetate dihydrate ($Zn(CH_3COO)_2{\cdot}2H_2O$) and thiourea ($H_2NCSNH_2$) were used as a starting materials and distilled water was used as a solvent. All ZnS thin films, regardless of a kind of complexing agents, had the hexagonal structure (${\alpha}$-ZnS) and had a preferred <101> orientation. ZnS thin films, with 4 M ammonia and with 4 M ammonia and 0.1 M $Na_2EDTA$, had the highest <101> peak intensity. In addition, their average particle size are 280 nm and 220 nm, respectively. The average optical transmittances of all films were higher than 60% in the visible range. The optical direct band gap values of films were about 3.6~3.8 eV.

• 한국산업보건학회지
• /
• 제4권2호
• /
• pp.189-197
• /
• 1994

Analytic methods for Cr(VI) level in industrial hygienic field were suggested by the National Institute for Occupational Safety and Health(NIOSH method 7600, 7604). There were growing needs for measurement of Cr(III) and Cr(VI) levels simultaneously. Two analytical methods were suggested to determine Cr(III) and Cr(VI) levels simultaneously. The one is method by using reversed phase high peformance liquid chromatography(HPLC) and the other is by using ion exchange HPLC. The purpose of this work was to evaluate the usefulness of these two analytic methods. For the difference of ionic charges of Cr(III)-ethylendiamine tetraacetic acid(EDTA) chelate and $CrO_4{^-2}$, we could detect them simultaneously by ion exchange HPLC. Also, we attempted to determine the levels of Cr(III) and Cr(VI) chelated with sodium diethyldithiocarbamate(NaDDTC) by using reversed phase HPLC. The confirmation of Cr(III) and Cr(VI) were checked by fraction collector and nameless atomic absorption spectrometer. The optimal conditions for the formation of Cr(III)-EDTA chelate were two hours incubation period with pH 5. Cr(III)-EDTA and Cr(VI) in EDTA solution were successfully separated by anion exchange column using $Na_2CO_3/NaOH$ mixture as mobile phase. Peaks of Cr(III)-EDTA and Cr(VI) in EDTA were identified at 5 minutes and 7 minutes of retention time respectively by the ion exchange HPLC. The formation of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were twelve hours incubation period. Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were separated by reversed phase column using methanol and water mixture as mobile phase. Peaks of Cr(VI)NaDDTC and Cr(III)-NaDDTC chelates were identified at 13 minutes and 26 minutes of retention time respectively by the reversed phase HPLC. Due to reduction of Cr(VI) to Cr(III), it seems to be not suitable for simultaneous determination of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates by reversed phase HPLS. Simultaneos determination of Cr(III) and Cr(VI) by ion exchange HPLC was more accurate and simple method.

• 한국식품과학회지
• /
• 제26권1호
• /
• pp.51-56
• /
• 1994

다시마를 다당류 분해효소인 Viscozyme, Celluclast, Ultrazyme을 사용하여 분해할 경우 Viscozyme과 Celluclast를 1 : 1로 혼합한 후 분해하는 것이 고형분 및 단백질 수율 그리고 상징액율면에서 가장 적절한 것으로 나타났으며 이때 고형분 수율은 34.5%였다. 염 또는 당의 농도를 $0.5{\sim}3.0%$범위로 하고 $100^{\circ}C$에서 2시간 가열하였을 때 고형분 농도 및 수율, 상징액율은 SHMP, sucrose, NaCl 및 EDTA-2Na순으로 높았으며 특히 EDTA-2Na를 2.5% 첨가시 고형분 수율이 63.1%까지 도달하여 NaCl과 sucrose를 첨가하였을 때보다 $30{\sim}80%$의 수율향상이 있었다. 관능적 성질은 열수추출한 것보다 효소처리 한 후 NaCl 또는 sucrose를 첨가하여 추출한 것이 전체적인 맛과 해조류 맛의 강도가 뚜렷하게 높았다.

• 한국수산과학회지
• /
• 제30권2호
• /
• pp.291-296
• /
• 1997

국내 연안에서 생산되는 해조류 즉, 갈조류에 속하는 미역, 다시마 그리고 톳, 녹조류에 속하는 파래, 그리고 홍조류에 속하는 우뭇가사리, 꼬시래기에 함유된 식이섬유소의 함량과 이들 해조류로부터 가용성 식이섬유소를 효과적으로 추출하고자 산과 알칼리 그리고 효소를 사용하였다. 그 결과, 미역의 식이섬유 추출에는 $1.5\%$의 탄산나트륨 용액, 또는 $2.0\%$의 $Na_2EDTA$가 효과적인 것으로 나타났다. 다시마는 $1.0\%$의 $Na_2EDTA$, 톳은 $2.0\%$의 탄산나트륨, 우뭇가사리와 꼬시래기는 $2.0\%$의 $Na_2EDTA$를 사용하였을 때 가용성 식이섬유의 수율이 높았다. 파래는 탄산나트륨, 수산화나트륨 그리고 $Na_2EDTA$ 중에서 특별히 효과적인 것은 없었으며 $2\%$농도에서 $17.49\~18.46\%$로 나타났다. 또한 추출시간과 온도를 검토한 결과, $100^{\circ}C$ 에서 해조중의 식이섬유 추출은 추출시간이 길수록 추출율이 높게 나타났으며, 추출온도에도 큰 영향을 받는 것으로 나타나 우뭇가사리와 꼬시래기는 $110\~$에서 1시간 추출시 각각 $38.48\%$와 $42.11\%$의 높은 수율을 나타내었다.

• 한국식품과학회지
• /
• 제26권1호
• /
• pp.44-50
• /
• 1994

미역 추출액의 효과적인 추출조건을 선정하기 위하여 5가지 추출 방법인 $Na_{2}EDTA$-끓임(방법 A). HCI-끓임(방법 B), $HCI-Na_{2}EDTA$-끓임(방법 C), $Celluclast-Na_{2}EDTA-HCI$-끓임(방법 D), $Ultrazyme-Na_{2}EDTA-HCI$-끓임(방법 E)을 비교하였다. 그 결과는 방법 D가 고형분 수율 63.14%와 단백질 수율 26.39%로 가장 높았다. 맛과 관계가 있는 아미노태 질소의 회수량은 870 ppm의 아미노태 질소농도를 보인 방법 C가 가장 높았고 방법 D(770 ppm), 방법 B(570 ppm), 방법 A(480 ppm), 대조구(270 ppm) 순으로 나타났다. 추출액의 정미 성분은 주로 alanine, aspartic acid, glutamic acid이었으며 미역 추출액의 유리 아미노산 총량은 방법 A(8.88 mg%), D(4.14 mg%), E(4.18 mg%)순으로 증가하였고 대조구(1.71 mg%)보다 $2.5{\sim}5.1$배 높았다. 미역 추출액의 관능적 성질 비교는 특히 Celluclast 처리한 방법 D가 유의적으로 적은 비린 냄새와 높은 해조류맛을 나타내었다. 따라서 방법 D를 가장 효과적인 방법임이 밝혀졌다.

• 한국토양환경학회지
• /
• 제1권2호
• /
• pp.51-60
• /
• 1996

본 연구에서는 산업폐기물로 버려지는 hematite와 ferrite를 이용하여 Mn-EDTA와 불소의 제거에 대한 실험을 행하였다. 제거율을 비교, 평가하기 위하여 무기오염물에 대하여 우수한 흡착능을 가지는 것으로 알려진 Na-bentonite를 실험에 포함하였다. Batch형태의 실험 결과, 망간에 대하여 여러 초기농도에서 ferrite-A는 48∼65 %, ferrite-B는 46∼57 %, hematite 의 경우 17∼26%o의 제거율을 갖는 것으로 나타났으며, Na-bentonite의 경우, 10∼23%의 제거율을 나타냈다. 불소의 경우에는 hematite가 53∼63%의 제거율을, ferrite-A가 54∼63%, ferrite-B는 20∼38%를 보였다. 연구 결과 Hematite와 Ferrite가 가지고 있는 특히 complex ion을 형성하는 무기 오염 물질 제거능이 Na-bentonite 보다 우수한 것으로 나타났다. 결론적으로 이러한 산화 광물과 Na-Bentonite 의 혼합을 통하여 차수재로서의 Na-bentonite의 역할을 증진시킬 수 있을 것이다.

• Restorative Dentistry and Endodontics
• /
• 제23권1호
• /
• pp.379-390
• /
• 1998

In endodontic treatment, calcium hydroxide has been used as intracanal medicament. Although calcium hydroxide should be removed thoroughly before permanent root canal filling, no effective method for its removal has been reported. Because of irregularity of root canal walls, root curvatures and anatomic variations, it is insufficient to remove calcium hydroxide from the canal wall only by mechanical instrumentation Considering the chemical effects of irrigants on calcium hydroxide, $Ca^{++}$ dissolving effect from two calcium hydroxide products is investigated, using dis- tilled water, NaOCl, citric acid and EDTA. Vitapex$^{(R)}$ 0.1g and calcium hydroxide 0.03g were dissolved in distilled water, 5% NaOCl, 50% citric acid and 17% EDTA respectively, at 1, 3, 5, 10min. time interval. The solution was filtered using filter paper(pore size $5{\mu}m$) and $Ca^{++}$ concentration was determined by ion chromatography. The result were as follows : 1. Distilled water, NaOCl, citric acid and EDTA abstracted more $Ca^{++}$ from calcium hydroxide than Vitapex$^{(R)}$ except NaOCl 1, 5, 10 time interval. 2. EDTA and citric acid abstracted more $Ca^{++}$ from Vitapex$^{(R)}$ and calcium hydroxide than distilled water or NaOCl. The overall result support the view that water-based calcium hydroxide product is easily removed than oil-based calcium hydroxide product and EDTA, citric acid are more effective in $Ca^{++}$ elution than NaOCl or distilled water.

• 대한화장품학회지
• /
• 제11권1호
• /
• pp.1-12
• /
• 1985

A strain of Pseudomonas aeruginosa was isolated from the spoiled product and its characteristics on various formaldehyde-releasing preservatives were investigated. This strain, P. aeruginosa FR, could utilize 1.0% of imidazolidinyl urea and 0.2% of DMDM hydantoin as a sole carbon and nitrogen source in the minimal salts medium. With the growth of the strain in minimal salts medium containing imidazolidinyl urea, formic acid was initially accumulated according to the decrease of formaldehyde concentration. It was suggested that formaldehyde dehydrogenase was involved in this oxidation process and could catalyze formaldehyde, imidazolidinyl urea, DMDM hydantoin and quaternium-15, but not bronopol. MICs of this strain to each preservation were 0.03% in formaldehyde, 1.0% in imidazolidinyl urea, 0.2% in DMDM hydantoin, 0.2% in quaternium-15 and 0.1% of EDTA-2Na. But the MICs were diminished about ten times when 0.01% of EDTA-2Na was added to the preservative systems. In actual challenge test, the eyeliner and the pack which contained paraben and imidazolidinyl urea were not able to be protected from this strain, but when 0.05% EDTA-2Na was added the products were sufficiently preserved.