• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.54-65
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• 2008

The purpose of this study was to determine the effect of sodium hypochlorite and steam autoclaving on the cyclic fatigue of nickel-titanium endodontic files. Two types of files with a .06 taper and #30 were used, $K3^{(R)}$ (SybronEndo, Glendora, California, USA) and Hero $642^{(R)}$(Micro-Mega, BesanCon, France). The files were divided into 6 experimental groups containing 10 files each group depending the soaking time in 6% sodium hypochlorite solution and number of cycles of steam autoclave. After sterilization, a cyclic fatigue test was performed on each file, and the fracture time was recorded in seconds. The control group underwent the cyclic fatigue test only. After the test, the surface characteristics of the files were observed using scanning electron microscopy (SEM). All groups containing the Hero 64~ files showed a similar cyclic fatigue fracture time. However, the cyclic fatigue fracture time with the $K3^{(R)}$ files was significantly shorter in groups which were treated with sodium hypochlorite than in the control group (P < 0.05), SEM revealed both Hero $642^{(R)}$ and $K3^{(R)}$ files to have significant corrosion on the file surface in groups treated with sodium hypochlorite, compared with the sharp and regular blades of the control group. $K3^{(R)}$ files showed more corrosion than the Hero $642^{(R)}$ files. Bluntness of the blades of the $K3^{(R)}$ file was observed in groups treated with steam autoclave. Although there was no obvious destruction on the surface of steam autoclaved Hero $642^{(R)}$ files, slight bluntness was observed. Sterilizing with a steam autoclave is much less destructive to $K3^{(R)}$ files than sodium hypochlorite. The longer time exposed to sodium hypochlorite, the more destructive pattern was shown on the blades of the files. Therefore, when using sodium hypochlorite solution, the exposure time should be as short as possible in order to prevent corrosion and increase the cyclic fatigue fracture time.

• Korean Journal of Poultry Science
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• v.40 no.4
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• pp.327-336
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• 2013

This study was conducted to examine the effect of spray-washing old hens (old laying hens, old molting hens and old breeder hens) carcasses with sodium hypochlorite (50 ppm) solution and vacuum packaging on the microbiological and physiochemical quality of breast meat during storage at $4^{\circ}C$. There were no significant differences of cooking loss and texture among breast meats from different birds with spray-washing by water or sodium hypochlorite solution before storage. The numbers of total aerobic bacteria of aerobically packaged and only water-washed breast meat were higher than 7 Log CFU/g (the limitation population for spoilage of meat) after 7 days of storage. However, the numbers of total aerobic bacteria of vacuum packaged breast meat washed by sodium hypochlorite solution were lower than 7 Log CFU/g even after 14 days of storage. The volatile basic nitrogen content of vacuum packaged breast meat were lower than 20 mg% (the limitation value for spoilage of meat) regardless of the washing method, while those of aerobically packaged breast meat washed by tap water and sodium hypochlorite solution were 41.1 and 20.1 mg%, respectively. In addition, lipid oxidation and change of pH in breast meat was inhibited by vacuum packaging when compared with that of aerobic packaged breast meat during storage. Therefore, the results indicated that the washing old hen's carcasses with sodium hypochlorite (50 ppm) solution and vacuum packaging could improve the shelf-life of meat from old birds. This result can provide the basic information for industry, which are seeking for export market.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.186-191
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• 2012

The sodium hypochlorite is widely used in endodontic treatment. While it is effective solution for disinfection of root canal system, complications during canal irrigation are rarely reported, especially in primary teeth. This report demonstrates that sodium hypochlorite extruding through the root apex might cause severe complications. A 4-year-old female patient was referred from local dental clinic to the emergency room for the management of sudden facial swelling and pain during re-endodontic treatment of the maxillary primary central incisor using sodium hypochlorite. The patient was given systemic steroids, antihistamines, antibiotics and analgesics and the maxillary primary central incisor was extracted to prevent secondary infection. Swelling began to subside after 2 days. A negative result was obtained from skin patch test with sodium hypochlorite. Thorough care must be taken in primary teeth to prevent the inadvertent injection of sodium hypochlorite to periapical tissues during root canal irrigation. When adverse reaction occurs, proper management such as analgesia, cold compression and adequate medication should be done.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.506-515
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• 1999

Dental practice can produce and spread some infectious diseases from patients to dentist, dental assistant, and dental labors. One possible method for preventing these cross-contamination is to immerse dental impression in chemical disinfectants. So for many investigators studied on the dimensional changes of dental impressions and on the surface qualities of stone casts made from impression following immersion in disinfectants. This study was proposed to evaluate some popular impression disinfectant combination from the point of dimensional stability. Impression was taken from dental arch-shaped metal model. Irreversible hydrocolloid and 3 elastomers(polyvinyl siloxane, polysulfide, polyether) were immersed in 3 disinfectants (2% glutaraldehyde, 1% povidone-iodine, 0.5% sodium hypochlorite) for 10 minutes and measured both cross-arch and anterior-posterior distance under stereo microscope to evaluate dimensional change. The results obtained were as follows: 1. Dimensional changes of irreversible hydrocolloid impression was statistically different in cross-arch and anterior-posterior distance when immersed in 2% glutaraldehyde solution and in anterior-posterior distance when immersed in 0.5% sodium hypochlorite solution from control group (p<0.05). 2. Dimensional changes of polyvinyl siloxane and polysulfide impression were not statistically different from control group (p>0.05). 3. Dimensional changes of polyether impression was statistically different in cross-arch distance when immersed in 0.5% sodium hypochlorite solution and in anterior-posterior distance when immersed in 1% povidone-iodine solution from control group (p<0.05). 4. In all cases, dimensional changes were less than 0.1% from the original dimension and concluded clinically acceptable.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.383-387
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• 2009

Multi-crystalline silicon surface etching without grain-boundary delineation is a challenging task for the fabrication of high efficiency solar cell. The use of sodium hydroxide - sodium hypochlorite (NaOH40% + NaOCl 12%) solution for texturing multi-crystalline silicon wafer surface in solar cell fabrication line is reported in this article. in light current-voltage results, the cells etched in NaOH 40% + NaOCl 12% = 1:2 exhibited higher short circuit current and open circuit voltage than those of the cells etched in NaOH 40% + NaOCl 12% = 1:1 solution. we have obtained 15.19% conversion efficiency in large area(156cm2) multi-Si solar cells etched in NaOH 40% + NaOCl 12% = 1:1 solution.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.55-62
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• 1984

This experimental study was made to evaluate the efficacy of root canal preparation of engine reamer versus hand reamer. Eighty extracted human teeth were prepared with the following treatments and devided into 4 groups; Group 1: Canal preparation with hand reamer, and irrigation with normal saline solution. Group 2: Canal preparation with engine reamer, and irrigation with normal saline solution. Group 3: Canal preparation with hand reamer, and irrigation with 3% hydrogen peroxide and 3.5% sodium hypochlorite solution. Group 4: Canal preparation with engine reamer, and irrigation with 3% hydrogen peroxide and irrigation with 3% hydrogen peroxide and 3.5% sodium hypochlorite solution. After decalcification, 5p. sections at levels 1-, 3-, and 5-mm from the apex were evaluated microscopically. The results were as follows; The effectiveness of hand reamer and engine reamer were equal in preparing the root canal at all levels from the apex, and were equal in normal saline solution groups, and 3% $H_2O_2$ and 3.5% NaOCl solution groups. Both in hand reaming groups and in engine reaming groups, some canal walls had still untouched portion, and canal irregularities and debris were still remained.

• Journal of Periodontal and Implant Science
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• v.13 no.1
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• pp.59.1-59.1
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• 1983

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.267-279
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• 1996

Microorganisms are implicated the endodontic treatment failures. Persistent endodontic infection may be the result of retention of microorganisms in the dentin of the root canal walls. Dentinal tubules of the root canal walls have been shown to harbor microorganisms. The purpose of this study was to investigate the invasion of microorganism into the root dentin and dentinal tubules. The effects of irrigation solutions and smear layer on bacterial colonization of root canal were evaluated using a scanning electron microscopy. Canals of extracted human teeth with single and straight canals were stepback prepared using normal saline. Tooth samples were divided into four groups according to the irrigation solutions -5 % sodium hypochlorite and normal saline-and smear layer treatment. The smear layer was removed by 5% NaOCl and 20% EDTA for 10 min respectively. After sterilization, they were incubated with each strains of Streptococcus sanguis, Enterococcus faecalis, Staphylococcus aureus and Escherichia coli. Sodium hypochlorite solution reduced the adhesion of microorganisms effectively compared to normal saline. The smear layer inhibited colonization of E. faecalis, S. aureus and E. coli in the root canals due to their blocking of dentianl tubules. But S. sanguis invaded dentinal tubules in the root canals without smear layer. It was suggested that bacterial attachment might be different according to the strains. Sodium hypochlorite inhibited bacterial attachment in the dentinal tubules dramatically. The absence or presence of smear layer affected bacterial invasion of the dentinal tubules.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.190-195
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• 1994

Studies were conducted to determine the potential of sodium hypochlorite(SHC) on the control of bacterial yellow blotch in cultivated oyster mushroom, Pleurotus ostreatus. SHC at the concentration of 80 ppm was effective on the control of Pseudomonas agarici causing yellow blotch in oyster mushroom except number 916 isolate. In vitro the mycelial growth was slightly inhibited at the concentration higher than 100 ppm of sodium hypochlorite, but retardation of the mycelial growth was soon recovered. Spray of SHC solution at the concentration of 40-50 ppm per day significantly reduced the incidence of the yellow blotch without impairing the growth of oyster mushroom in field culture. However, the higher concentration of SHC(67 ppm) induced yellow brown or dark gray in color and deformed cap and elongated stripe in morphology of fruiting body. Results indicate that periodical spray of sodium hypochlorite seems to be the recommendable method for protection against bacterial yellow blotch disease in oyster mushroom without reducing food quality.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.42-48
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• 1998

Physicochemical properties of waxy maize starch and oxidized waxy maize starch with sodium hypochlorite $(0{\sim}60\;mg\;CL_2/g\;starch,40^{\circ}C,\;pH\;10,\;3.0\;hr)$ were studied. As sodium hypochlorite concentration was increased, the content of crude lipid and crude protein of the oxidized starch were decreased. And crude protein content and whiteness was considered to show negative regression. However, the crude ash content of the oxidized starch increased significantly with oxidation and bore a positive regression to the chlorine content. There was a progressive increase in the carboxyl content with increasing oxidant level. After pasting in hot water and cooling, viscosity of the oxidized starches were drastically lower than that of native starch . As carboxyl contents of the oxidized starch increased, the solubility and swelling power was increased. When waxy maize starch treated with 0, 1.5, 3.0 and 6.0% sodium hypochlorite, temperature of initial gelatinization of oxidized starch was shown to 65, 65, 60 and $50^{\circ}C$, respectively. The oxidized waxy maize starches also form clearer pastes. Water binding capacity of the oxidized starch decreased as the degree of carboxyl group substitution increased. Waxy maize starch has polygonal and some round granules which range from about 3.7 to $20\;{\mu}m$ in diameter. Surface appearance of the waxy maize starch became rough when oxidized with sodium hypochlorite. When homogenate of the oxidized waxy maize starch solution and corn germ oil was stored under room temperature for 24 hours, the emulsion stability was considered to depend on starch concentration and degree of substitution.