Different Concentrations Of NaOCl Research Articles

Tissue dissolution and modifications in dentin composition by different sodium hypochlorite concentrations.

ABSTRACTSodium hypochlorite (NaOCl) remains the most used irrigation solution during root canal preparation because of characteristics such as wide-spectrum antimicrobial activity and organic tissue dissolution capacity. However, these solutions can alter dentin composition and there is no consensus on the optimal concentration of NaOCl to be used. Objectives To determine the organic matter dissolution and changes in dentin chemical composition promoted by different concentrations of NaOCl over time. Material and Methods: Fragments of bovine muscle tissue were weighed before and after 5, 10, and 15 min of immersion in the groups (n=10): G1- 0.9% saline solution; G2- 1% NaOCl; G3- 2.5% NaOCl; and G4- 5% NaOCl. Bovine dentin fragments were subjected to the same irrigants and absorption spectra were collected by Attenuated Total Reflectance of Fourier Transform Infrared Spectroscopy (ATR-FTIR) before and after 0,5, 1, 2, 3, 5, 8, and 10 min of immersion in the solutions. The ratios of the amide III/phosphate and carbonate/phosphate absorption bands were determined. The tissue dissolution and carbonate/phosphate ratios were submitted to the two-way analysis of variance (ANOVA) with Tukey’s multiple-comparison test (α<0.05) and to the one-way analysis of variance with Tukey’s (α<0.05). The amide III/phosphate ratio was analyzed by Friedman test (α<0.05) and the Kruskal-Wallis test with Dunn’s post-hoc (α<0.05).Results The increase in NaOCl concentration and contact time intensified the dissolution of organic matter and dentin collagen with reduction in the amide III/phosphate ratio. Significant differences between all groups (p<0.05) were observed in the dissolution of organic matter at 10 min and in the amide III/phosphate ratio between the saline solution and 5% NaOCl at 5 min. The carbonate/phosphate ratio decreased significantly in G2, G3, and G4 after 0,5 min of immersion (p<0.05), but more alterations did not occur in the subsequent periods (p>0.05). Intergroup differences were not observed in this ratio (p>0.05).Conclusions The increase in the exposure time and in the concentration of NaOCl solution lead to an increase in the tissue dissolution and dentin collagen deproteination. Furthermore, some carbonate ions are removed from the dentin inorganic phase by the NaOCl.

English

Bacteria present in biofilm show an increased resistance to antimicrobial activity of endodontic irrigants, and the persistence of these microorganisms after chemomechanical preparation may lead to endodontic treatment failure. Thus, the aim of this study was to evaluate the effectiveness of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) to reduce E. faecalis biofilm biomass. Biofilms built by Enterococcus faecalis ATCC 29212 in polystyrene 96-microtiter plate wells were exposed to different concentrations of NaOCl (1, 2.5 and 6%) and CHX (0.12, 0.2 and 2%) for three different time periods (1, 3 and 10 min). The reduction of the biofilm biomass was evaluated by measuring the optical density with a microplate absorbance reader. All of the NaOCl solutions were significantly more effective than any of the CHX solutions tested, regardless of the time of exposure (P 0.05); by contrast, after 10 min of exposure to the NaOCl the biofilm was not significantly different from the positive control without biofilm (P > 0.05). Moreover, considering the period of times used in this study (1 to 10 min), no significant differences were observed among different concentrations for each desinfectant. In conclusion, none of the tested concentrations of CHX showed an ability to decrease the biofilm biomass. On the other hand, even the most diluted NaOCl solution (1%) reduced the biofilm biomass to a level that was compatible with the complete disruption of the biomass structure. Key words: Sodium hypochlorite, chlorhexidine, biofilm, endodontic infection.

A New Method to Assess Available Chlorine in Small Volumes of Liquid

IntroductionThere is no robust and simple way to quantify available chlorine from small volumes such as human root canals. Therefore, a new method was developed and assessed. MethodsStandardized size-40 paper points were soaked in a 15% (w/v) potassium iodide solution for 1 minute. Subsequently, the paper points were placed in an incubator and dried at 110°C for 4 hours. The paper points (n = 5 per measurement) were then dipped in different concentrations of NaOCl and photographed under standardized conditions in RAW format. The pictures were imported to image processing software and adjusted to the standardized background. The red, green, and blue levels of the paper points were assessed at a predefined area. Inverse regression was used to determine NaOCl concentration from red, green, and blue values, with both explanatory and outcome variables log-transformed to base 10. ResultsThe red value measurements were chosen for further analysis based on a comparison of the coefficient of determination (R2) and a residual analysis. The method was applied to concentrations of NaOCl between 0.0001% and 1% (R2 = 0.92). In this range, NaOCI concentrations could be assessed with an error not larger than 3-fold the determined concentration. ConclusionsThe present method proved to be robust to determine the order of magnitude of available chlorine that is present in a small volume. This should be useful for endodontic research.

Antibacterial efficacy of endodontic irrigation solutions against Enterococcus faecalis

Methods Forty-one extracted single-rooted teeth were included in the present study. After content removal and autoclaving, they were divided into eight groups among which two were used as positive and negative controls. The remaining six groups were instrumented and irrigated with solutions containing 17% EDTA, sterile saline solution, and different concentrations of NaOCl. In addition, chlorhexidine 2% was also used in three groups. Microbiological evaluation was performed after 30 minutes, and 24 hours, respectively. E faecalis strain ATCC 29212 was used for culture tests. Statistical analysis was performed using non-parametric tests.

Influence of EDTA and dentine in tissue dissolution ability of sodium hypochlorite

This study verified whether ethylenediaminetetraacetic acid (EDTA) influences the pulp tissue dissolution capability of different concentrations of NaOCl, in the presence of dentine. NaOCl and EDTA solutions were simultaneously mixed in flasks either containing a dentine disc or those not containing a dentine disc. Previously weighed bovine pulp tissues were immersed in the solutions for 5, 15 and 30 min. The weight loss was measured. The dissolution tests were performed in triplicate. Univariate analysis of variance, along with further Tukey's honestly significant difference pairwise comparisons, was used to verify the effect of EDTA, different concentrations of NaOCl, dentine and time of incubation on the tissue dissolution. Higher concentrations of NaOCl increased the tissue dissolution. EDTA reduced the capacity of NaOCl to dissolve pulp tissue, even in presence of dentine. Dentine negatively affects the capacity of NaOCl to dissolve pulp tissue. In conclusion, the presence of EDTA and dentine negatively affects the tissue dissolution ability of NaOCl.

Efficacy of different concentrations of sodium hypochlorite and chlorhexidine in disinfection of contaminated Resilon cones

Objectives: The aim of this study was to evaluate the effectiveness of different concentrations of Chlorhexidine (CHX) and sodium hypochlorite (NaOCl) in disinfecting contaminated Resilon cones within one minute. Study design: Fifty Resilon cones were divided into seven experimental groups and three control groups of 5 cones each. The cones of experimental groups were contaminated with Entrococcus faecalis and subsequently disinfected with different concentrations of NaOCl or CHX. The cones were then transferred into glass tubes containing thioglycollate media and incubated for 7 days. The tubes were examined for turbidity every 24 hours, and if bacterial growth occurred, samples were plated, incubated, gram stained and observed under microscope to confirm E.faecalis growth. Negative, positive, and washing control groups were also used. Results: All the positive and washing control showed profound E.faecalis growth. All the cones disinfected with CHX showed bacterial growth; however, no E.faecalis growth occurred in any samples disinfected with NaOCl. Conclusion: Sodium hypochlorite, at concentrations of 0.5 to 5.25%, is an effective agent for disinfection of contaminated Resilon cones within one minute; however, chlorhexidine is unable to disinfect Resilon cones during one-minute exposure. Key words: Chlorhexidine, sodium hypochlorite, resilon, entrococcus faecalis.

Evaluation of radicular dentin erosion and smear layer removal capacity of Self-Adjusting File using different concentrations of sodium hypochlorite as an initial irrigant

The aim of this study was to evaluate Self-Adjusting File (SAF) in the removal of smear layer and impact on the dentin surface using sodium hypochlorite (NaOCl) as an initial irrigation solution at 3 different concentrations combined with 1% EDTA. In addition, the erosive effect of this dual irrigation regime was examined. Root canal preparations were performed in 30 teeth using the SAF with a continuous irrigation device (Vatea) in a closed system in which the apical foramen was sealed. The vibration mode was on for 5 minutes during the preparation. Three different concentrations of NaOCl (1.3%, 2.6%, and 5.25%) and 1% EDTA were used for continuous irrigation. The final flush was also performed using NaOCl with the vibration mode on. The roots were split longitudinally and subjected to scanning electron microscopy (SEM). The presence of the smear layer was scored using a 5-point scoring system, and the erosive capacity of the irrigants were scored using a 3-point scoring system. The results showed no significant difference in smear layer removal among different concentrations of NaOCl and among the regions. Clean dentin surfaces were observed in 80%, 70%, and 70% with a score of 1 or 2 of the apical thirds using 1.3%, 2.6%, and 5.25% NaOCl, respectively. The 1.3% and 2.6% NaOCl solutions showed similar erosion patterns on the root canal walls (P > .05); however, 5.25% NaOCl caused severe erosion (P < .05). When using the SAF with continuous irrigation and vibration, lower concentrations of NaOCl and EDTA can be recommended for efficient clinical removal of the smear layer even in the apical thirds and to avoid excessive erosion of root dentin.

Determination and Improvement of Microbial Safety of Wheat Sprouts with Chemical Sanitizers

In this study, total aerobic mesophilic bacteria (TAMB), total coliform (TC), yeasts and moulds (YM), and Escherichia coli, Salmonella, and Staphylococcus aureus counts of wheat seeds and sprouts germinated for 9 days under different relative humidity (RH) (90% and 95%) and temperatures (18 °C, 20 °C, and 22 °C) were determined. The disinfection capabilities of sodium hypochlorite (NaOCl) (100, 200, and 400 ppm) and hydrogen peroxide (H(2)O(2)) (3% and 6%) on wheat seeds/sprouts were also investigated. It has been found that native TAMB, TC, YM, and E. coli population significantly increased (p<0.05) with the germination; however, no Salmonella and S. aureus were detected on the seeds and/or sprouts. Again, increasing the temperature and RH resulted in a rapid proliferation of microorganisms. On the other hand, E. coli population could be completely eliminated by the treatment of different concentrations of NaOCl or H(2)O(2) before the germination of wheat seeds. Again, increasing the NaOCl and H(2)O(2) concentrations resulted in additional reductions of TAMB, TC, and YM population; and the highest reductions in sprouts were observed when the seed was soaked in 400 ppm NaOCl for 30 minutes followed by tap water wash and germination for 9 days. Population reduction of 1.46 log colony-forming unit (cfu)/g of TAMB, 1.97 log cfu/g of YM, and 0.84 log cfu/g of TC in sprouts was achieved when compared with the control. The chemical sanitization did not negatively affect the germination capability of the seeds. Therefore, soaking the seeds in 400 ppm of NaOCl for 30 minutes followed by a germination environment of 18 °C and 90% RH was found to be the most appropriate germination condition for wheat sprouts with reduced microbial population.

The effect of grain mould fungi on sorghum malt quality and its management during malting

The effect of sodium hypochlorite (NaOCl) at various concentrations during steeping in reducing the growth of grain mould fungi and the improvement of malt quality was tested. Significant (P ≤ 0.05) differences in grain mould fungal frequency, percentage germination and root length were observed between different concentrations of NaOCl. Fungal frequency was reduced by up to 98% at 1.75 and 3.5% NaOCl. However, germination and root length of grains were negatively affected at NaOCl concentrations above 0.43%. High germination (>80%) was recorded at concentrations ≤ 0.43% NaOCl while this was reduced to <70% at higher concentrations. Similarly, the longest root length (32.25 mm) was recorded in seedlings treated with 0.43% NaOCl with a decline in root elongation, particularly at the higher (1.75 and 3.50%) concentrations tested. It was concluded that treating of sorghum grains with appropriate concentrations of NaOCl may reduce the contamination of grains by mould fungi, improve germination vigour and hence, the quality of malt.

COMPARAÇÃO DE MÉTODOS DE DESCONTAMINAÇÃO USADOS NA FASE INICIAL DO ESTABELECIMENTO EM CULTURA IN VITRO DE BANANA

Four decontamination methods for in vitro culture of banana ( Musa AAB cv. Maca) explants were compared. Commercial crop rhizomes were used as the explant source. Different sizes of explants obtained from axillary buds were submersed in different concentrations of NaOCl for each different period of time. After being reduced to 8mm x 5mm x 5mm, explants were transferred to modified MS media, which were kept in the dark for 10 days, followed by growth chamber at 28°C +/- 2°C with 16h light. Best results were obtained with 40mm x 20mm x 20mm or 40mm x 15mm x 15mm explants, immersed once or twice in 3.5% NaOCl. Higher contamination levels were observed 15 days after the beginning of the experiment; at 1% NaOCl, however, 96.67% contamination was observed after 3 days. Bacterial incidence was higher than fungal. KEY-WORDS: Banana cv. Maca; tissue culture; superficial sterilization; Musa AAB.

Pulp-Dissolving Ability of Several Endodontic Irrigants: A Spectro-Photometry Evaluation

The aim of this study is to test the dissolving action of different concentrations of NaOCl (0.5%, 2.5% and 5%) and EDTA 17% on bovine pulp tissue, testing solutions at three different times (1, 5, 10 minutes), 100 mg.of dental pulp placed into a becker with 20 ml of solution was evaluated using a spectrophotometer. A solution of NaOCl 5% showed the highest solubility value. Samples treated with 2.5% NaOCl showed solubility values of 0.98 in one minute, 29.1 in five minutes and 57 in ten minutes. Groups treated with NaOCl 0.5% showed small dissolving modifications. 17% EDTA showed the lowest values of solubility. 5% NaOCl solution showed highest pulp dissolving ability, even a 2.5% solution showed high dissolving ability but in longer times.

The influence of organic load on the antimicrobial activity of different concentrations of NaOCl and chlorhexidine in vitro.

To evaluate bacterial growth after contact with sodium hypochlorite (NaOCl; 1 and 5%) and chlorhexidine (CHX; 0.12, 0.5 and 1%) in vitro with or without the addition of organic material (bovine serum albumin (BSA) 0.5%). Bacterial samples (American Type Culture Collection (ATCC)) of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis and Fusobacterium nucleatum were kept in contact with each irrigating solution for varying intervals of time: immediately (t0), 5 min (t5), 15 min (t15) and 30 min (t30). Each test was repeated 10 times. In half of the specimens, 0.5% BSA was added as organic material in an attempt to simulate the organic tissue present in the root canal system. Bacterial growth under appropriate condition of incubation was evaluated and compared for each microorganism at all time intervals. A 0.12% CHX solution did not eliminate E. faecalis at any time interval. One percent CHX eliminated all strains, as did both NaOCl concentrations. BSA did not interfere substantially with the antimicrobial activity of any of the irrigating solutions. Under the condition of this study, a 0.12% CHX solution was ineffective at killing E. faecalis.

The Effect of Various Concentrations of Sodium Hypochlorite on the Ability of MTAD to Remove the Smear Layer

Various organic acids, ultrasonic instruments, and lasers have been used to remove the smear layer from the surface of instrumented root canals. The purpose of this study was to investigate the effect of various concentrations of sodium hypochlorite (NaOCl) as an intracanal irrigant before the use of MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) as a final rise to remove the smear layer. Ten operators, using a combination of passive step-back and rotary 0.04 taper, nickel-titanium files, prepared 80 single- and multirooted human teeth. Distilled water, four different concentrations of NaOCl, or MTAD was used as intracanal irrigant. The canals were then treated for 2 min with 5 ml of one of the following solutions as a final rinse: 5.25% NaOCl, sterile distilled water, 17% EDTA, or MTAD. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portion of each canal were examined under a scanning electron microscope. The results show that although MTAD removes most of the smear layer when used as an intracanal irrigant, some remnants of the organic component of the smear layer remain scattered on the surface of the root canal walls. The effectiveness of MTAD to completely remove the smear layer is enhanced when low concentrations of NaOCl are used as an intracanal irrigant before the use of MTAD as a final rinse. This regimen does not seem to significantly change the structure of the dentinal tubules.

Antimicrobial activity of different concentrations of NaOCl and chlorhexidine using a contact test.

The purpose of this study was to analyze the in vitro antimicrobial activity of sodium hypochlorite (1% and 5%) and chlorhexidine (0.12%, 0.5% and 1%). Bacterial samples (ATCC) of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis and Fusobacterium nucleatum were submitted to a contact test. Solutions were evaluated at different time intervals: immediately, 5 min, 15 min, and 30 min after contact and repeated 10 times. The results of the contact test showed that 0.12% chlorhexidine did not eliminate E. faecalis at any time interval, while 0.5% and 1% chlorhexidine and 1% and 5% sodium hypochlorite did. These results permit us to conclude that to obtain better antimicrobial activity, chlorhexidine in a concentration greater than 0.12% should be used.

A simple model to demonstrate the electronic apex locator.

To describe and evaluate a newly developed model for demonstrating and teaching the use of electronic apex locators. A phantom model, master jaw model and extracted human teeth were used to construct the demonstration model with alginate impression material as the periapical conductive medium. The model was validated in a series of length determinations with apical foramina enlarged to 0.20, 0.30 and 0.45 mm diameter, and the stability of the model was evaluated up to 45 h after construction. All evaluations were conducted with the Root ZX apex locator with 2.65 and 5.25% NaOCl in the canals. Most length measurements were within 1 mm of actual root length (range: -2.2 to +0.21 mm) and did not change significantly over 45 h for teeth with foramina of 0.3 mm or less. Measurements for teeth with wide (0.45 mm) apices were stable up to 28 h. NaOCl concentration did not significantly affect the readings. A simple, inexpensive model can be manufactured from plastic dental jaws, natural teeth and alginate impression material to demonstrate electronic working length measurement. The model is stable for many hours and provides consistent results with different concentrations of NaOCl in the canal and various apical diameters. The model is a useful teaching aid but needs further evaluation and refinement before use in research applications.

Protocol optimisation for micropropagation of Ethiopian yam

Yam (Dioscorea spp.) is a monocotyledonous tuber forming tropical vine, which belongs to the family Dioscoreaceae, and genus Dioscorea. Yam is well known for medicinal properties, as well as nutritional values. Conventional propagation of yam is limited by low propagation rates; hence, in vitro propagation provides the best alternative to overcome such limitations. The objective of this study was to optimise a protocol for in vitro micro-propagation of Ethiopian yam (D. alata, bulcha variety). Explants were obtained from young leaves of bulcha variety, and sterilised using different concentrations of NaOCl, for different time exposures. Sodium hypochlorite (1%) at 15 minutes exposure time, showed 100% survival of explants. The combination of 0.5 BAP with 1mgl-1 NAA was the best concentration for shoot induction. For shoot multiplication, BAP at 1.5 mg l-1 gave the highest shoots per explants (7.28±0.07), with shoot length of 8.72±0.43 cm. MS medium with 2.0 mg l-1 NAA and 1.5 mg l-1 IBA gave the highest rooting percentage and root number (10.6±0.44), with a root length of 13.80±0.44. In vitro acclimatised plantlets,which were transferred to a greenhouse for hardening, had 90% survival rate on soil medium. Thus, for micropropagation of bulcha yam variety, MS + 1.5 mg l-1 and MS plus 2.0 mg l-1 NAA + 1.5 mg l-1 IBA is the best phytohormonal combination for shoot multiplication and invitro rooting, respectively.