• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.379-390
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• 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.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.538-548
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• 1995

Calcium hydroxide has been used not only as pulp capping and pulpotomy agents in the operative dentistry, but dressing and temporary filling materials in root canal treatment. Calcium hydroxide was known to stimulate odontoblast to produce new reparative dentin and to eliminate microorganims effectively in the infected root canals. The purpose of this study was to evaluate the effect of calcium hydroxide solution on cultured L929 cells and its antibacterial effect on several streptococci. Calcium hydroxide solution (0.121g/100ml) was added to L929 cells and cell viability was measured using 3-(4,5-dimethylthiazol-2-yl) -2,5-dimethyltetrazolium bromide (MTT) and neutral red (NR) dye. Calcium hydroxide solution (20, 40, 60, 80, 100 and $150{\mu}l$) was added to L929 cells in 96-well microplates for 1, 4 and 24 hours respectively. Cell viability was gradually decreased when the volume and exposure time of calcium hydroxide solution were increased. When $150{\mu}l$ of calcium hydroxide was applied to L929 cells for 24 hours, there was more than fifty percent reduction of cell viability. Calcium hydroxide solution (20g/100ml) showed antibacterial effect against S. uberis, S. intermedius and S. mitis after thirty-second exposure. But 0.121g/100ml concentration of cacium hydroxide solution exhibited no antibacterial effect on six streptococci after one-hour exposure.

• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.632-643
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• 2002

The purpose of this study was two-fold. First was to evaluate whether the molecular sieving model was appropriate for ionic dissociation experiment. Second was to compare the dissociation of calcium and hydroxyl ions from five types of calcium hydroxide pastes (Pure calcium hydroxide paste, DT temporary $dressing^{\circledR},{\;}Metapaste^{\circledR},{\;}Chidopex^{\circledR},{\;}Metapex^{\circledR}$) in three vehicles (aqueous, viscous and oily) and the antibacterial effect. Each calcium hydroxide pastes was placed into 0.65ml tube with cap and then 15% polyacrylamide gel was placed onto calcium hydroxide pastes. After the gel was hardened, the tubes were filled with tridistilled water (pH 7.14) and closed with cap. The tubes were stored in $37^{\circ}C$ 100% incubator The pH reading and the concentration of calcium ions were taken at 1, 4, 7. 10, and 14 days. The brain heart infusion agar plates with S. mutans and A. actinomycetemcomitans were used far antibacterial activity test. Middle of agar plate was filled with the calcium hydroxide pastes. The plates were incubated at $37^{\circ}C$ and observations were made to detect the zones of inhibition. These data were evaluated statistically by use of the analysis of variance and duncan test. The results were as follows. 1. In fresh mixing state, the pH of five types of calcium hydroxide pastes were measured between 12.5 and 12.8. 2. The pH was increased in all five types of calcium hydroxide pastes compared with control group. In 14 days, Pure calcium hydroxide paste (11.45) and DT temporary $dressing^{\circledR}$ (11.33) showed highest pH, followed by $Metapaste^{\circledR}$ (9.49), $Chidopex^{\circledR}$ (8.37) and $Metapex^{\circledR}$ (7.59) 3. Calcium was higher in all five types of calcium hydroxide pastes compared with control group. In 14 days, Pure calcium hydroxide paste (137.29 mg%) and DT temporary $dressing^{\circledR}$ (124.6 mg%) showed highest value, followed by $Metapaste^{\circledR}$ (116.74 mg%), $Chidopex^{\circledR}$ (111.84 mg%) and $Metapex^{\circledR}$ (60.22 mg%). 4. The zones of bacterial inhibition were seen around all five types of calcium hydroxide pastes. $Chidopex^{\circledR}{\;}and{\;}Metapex^{\circledR}$ groups which include iodoform were observed significantly larger zone of inhibition in A. actinomycetemcomitans compared with the other calcium hydroxide groups (p<0.05) However, $Metapex^{\circledR}$ showed the least antibacterial effect on S. mutans compared with other groups (p<0.05). The molecular sieving model was found to be acceptable in dissociation experiment of hydroxyl and calcium ions when compared with the previous tooth model study. But this model was not appropriate for the antibacterial test.

• Journal of the Korean Ceramic Society
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• v.33 no.12
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• pp.1331-1338
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• 1996

In order to investigate the reaction in the system of fly ash-sulfuric acid-calcium hydroxide the hydrates were produced by the addition of Ca(OH)2 to fly ash activated with sulfuric acid at various temperatures. And then they were characterized by XRD. SEM and TG-DTA. It was found that in the reaction of fly ash with sulfuric acid fly ash was not decomposed but Al2O3 and SiO2 component in it were activated. The addition of calcium hydroxide into this system resulted in the formation of ettringite and calcium silicate hydrate (C-S-H) As the concentration of sulfuric acid and reaction temperature increased the amount of calcium hydroxide decreased fast. At this time gypsum produced by the reaction calcium hydroxide with sulfuric acid was consumed to form ettringite. Accordingly the formation of ettringite increased with calcium hydroxide and reaction time. And it showed faster than the formation of C-S-H.

• Elastomers and Composites
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• v.40 no.1
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• pp.12-21
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• 2005

In this work, magnesium carbonate and calcium hydroxide as metallic crosslinking agent were added to chlorosulfonated polyethylene rubber (CSM) emulsion to enhance the mechanical properties of emulsion film such as tensile strength, elongation at break, and tear strength and crosslinking density, thermal features, and surface energy were also investigated. Crosslinking density of the CSM emulsion film with increasing the amount of magnesium carbonate and calcium hydroxide increased, leading to the enhancement of water resistance. It was shown that compared with calcium hydroxide, magnesium carbonate had a little higher crosslinking density and $T_g$ value. The surface energy and mechanical characteristics of the CSM emulsion film, however, showed somewhat different behaviors. The highest surface energy, tensile strength, and tear strength were observed when 0.75% for magnesium carbonate and 1.0% for calcium hydroxide were added respectively. Therefore, it can be concluded that as metallic crosslinking agent to improve water resistance and mechanical properties of the CSM emulsion, magnesium carbonate is more preferable to calcium hydroxide.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.272-288
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• 2000

Calcium hydroxide is used as a root canal medicament with its several pharmacological effects. However, it has been known that the usage of calcium hydroxide in the root canal system before canal filling with gutta-percha and zinc oxide eugenol-based cement induced change in the properties of root canal cement which might adversely affect sealing ability of the canal filling. The purpose of this study was to identify the reactivity of calcium hydroxide-eugenol compound made from chemical interaction of between calcium hydroxide and zinc oxide eugenol. Chemical properties of calcium hydroxide, eugenol, zinc oxide eugenol, calcium hydroxide-eugenol and calcium hydroxide-zinc oxide eugenol compound were analyzed using XRD. FT-IR Spectrophotometer and FT-NMR Spectrometer. The results were as follows: 1. The compound made from interaction between calcium hydroxide and zinc oxide eugenol was as follows : 2. Calcium hydroxide was shown to make chemical bond (ionic bond) with eugenol. 3. Since bonding between $Ca^{2+}$ and eugenol is simple ionic nature, under water existence, calcium hydroxide-eugenol compound may be ionized easily and its physical property be deteriorated.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.177-184
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• 2013

Calcium hydroxide mixture medicaments can nearly be considered to be the ideal primary tooth filling material. However, long-term application of calcium hydroxide combinations as an intra canal medicament softens dentin. The aim of this study was to evaluate the effect of calcium hydroxide on the microhardness of root dentin of primary tooth. For the study, 60 extractedprimary incisors were divided into 3 groups (no medicament, calcium hydroxide/iodorform mixture, and calcium hydroxide/distilled water mixture). After the cleansing and shaping of canals, calcium hydroxide medicaments were applied and stored for different periods of time (1, 7, 30, 90 days). The root was horizontally sectioned into 2 mm thick specimens and the microhardness was measured using Vickers microhardness tester. The results were as follows : Root dentin microhardness of primary teeth decreased with long term exposure to calcium hydroxide medicaments according to the experimental period and showed statistically significance (p < 0.05). Root dentin microhardness of primary tooth filled with calcium hydroxide mixed with distilled water showed more decrease than filled with Vitapex and showed statistically significance (p < 0.05). Root dentin microhardness of a control group without exposure to calcium hydroxide decreased according to the experimental period and showed statistically significance (p < 0.05).

• Restorative Dentistry and Endodontics
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• v.26 no.2
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• pp.111-120
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• 2001

Calcium hydroxide pastes is widely used in conventional endodontics. Along with the expanded clinical use of calcium hydroxide, literatures suggest mixing calcium hydroxide with other substance. Among added substances the vehicle plays the most importance role in the overall process because it is directly related with the velocity of ionic dissociation of $Ca^{2+}$ and OH ion. In this study, we evalutated and compared periapical tissue response and root resorption after canal was filled with mixture of saline and calcium hydroxide(Junsei Chemical Co.. Japan) as a aqueous vehicle, Metapaste(Meta Co., Korea) as a viscous vehicle paste, Vitapex(Neo Dental, Japan) as a oily vehicle paste and IRM(Caulk Dentsply, USA) in replantation of rat molar. A total of 31 maxillary first molars of Sprague-Dawley female rats, 30 days old were used. The upper 1st molar was extracted and the mesiobuccal canal was filled with mixture of saline and calcium hydroxide, Metapaste, Vitapex. IRM and then replanted. Rats were sacrificed 3 weeks after replantation. the maxillae were removed. section of 4 micron were cut and stained with hematoxylin-eosin, Apical tissue response were observed under light microscope. The results were as follows: 1. Saline mixing group and Metapaste group were significant different in fibrous capsule width compared to Vitapex group and IRM group(P<0.05). 2. Saline mixing group. Metapaste group. Vitapex group and IRM group did not prevent root resorption and there were no statistical difference. 3. In saline mixing group and Metapaste group. loss of pastes were observed in all samples. From the results of our study. we observed loss of pastes in saline mixing group and Metapaste group because of water soluble property and assumed it was related to inflammation in apical area and sealing ability of material. So, we should study and develop calcium hydroxide vehicle which is easily removed and more stable and because of only 3 weeks observation we need more evaluation in long period.

• Korean Journal of Medicinal Crop Science
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• v.23 no.2
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• pp.150-154
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• 2015

Physiological disorders such as symptoms in leaf colored with brown spots are so many occurred in ginseng garden cultivated with paddy soil. This study was carried out to inhibit the symptoms of brown-colored leaf in 3-year-old ginseng by fertilizing calcium hydroxide [$Ca(OH)_2$] of 100 ~ 400 kg per 10a on paddy soil before transplant of seedling. Soil pH was rapidly increased, while Fe was decreased in soil by the increase of application level of calcium hydroxide. Soil pH was increased from 4.53 to 6.18 when calcium hydroxide was fertilized at level of 100kg per 10a. The content of Fe in ginseng leaf was decreased more than the control by fertilizing calcium hydroxide in soil. Ratio of brown-colored leaf and plant height and leaf area were decreased by the increase of calcium hydroxide. Ratio of survived root and yield of root showed the peak at the application level of 100 kg per 10a, and both of them were gradually decreased by the increase of calcium hydroxide. The decrease of missing plant rate above the application level of 200 kg per 10a had a negative effect on the decrease of yield of root.

• Research in Plant Disease
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• v.10 no.1
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• pp.82-85
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• 2004

Bacterial soft rot by Erwinia carotovora subsp. carotovora is one of the diseases causing the biggest damages in Chinese cabbage cultivation. This study was conducted to evaluate on suppressive effect of calcium fertilizer to bacterial soft rot of Chinese cabbage. Seven calcium fertilizers were selected for evaluation. And screening was conducted to select effective agents for controlling bacterial soft rot. When applied by the nursery test condition using mineral oil inoculation method with Chinese cabbage, calcium hydroxide had more suppressive efficacy than any other calcium fertilizer, While nitrogen fertilizer was induced the disease, calcium hydroxide was suppressed soft rot disease in field test as well as seedling test. Treatment of calcium+nitrogen fertilizer as well as calcium only showed a significant control effect in the field experiment with Chinese cabbage 'Sanchon' in 2003.