NaOCl alternative options Steier, L.; Albino Souza, M.; Poli de Figueiredo, J. A.
British dental journal,
06/2024, Volume:
236, Issue:
11
Journal Article
Sodium hypochlorite (NaClO) is a commonly used reagent for membrane cleaning in membrane bioreactors (MBRs), while it, being a kind of disinfectant (oxidant), may impair viability of microbes or even ...totally inactivate them upon its diffusion into mixed liquor during membrane cleaning. In this study, we systematically examine the effects of NaClO on microorganisms in terms of microbial cell integrity, metabolism behaviours (key enzymes), and intracellular reactive oxygen species (ROS) under various NaClO concentrations. Different proportions of microbial cells in activated sludge were damaged within several minutes dependent on NaClO dosages (5–50 mg/g-SS), and correspondingly organic matters were released to bulk solution. Inhibition of key enzymes involved in organic matter biodegradation, nitrification and denitrification was observed in the presence of NaClO above 1 mg/g-SS, and thus organic matter and nitrogen removal efficiencies were decreased. It was also demonstrated that intracellular ROS production was increased with the NaClO dosage higher than 1 mg/g-SS, which likely induced further damage to microbial cells.
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•Cell lysis occurred within initial several minutes at NaClO dosages of 5–50 mg/g-SS.•Heterotrophic metabolism was inhibited when NaClO concentration was above 1 mg/g-SS.•Key enzymes for nitrogen removal were lowered at NaClO dosage higher than 1 mg/g-SS.•Increased production of intracellular ROS was observed in the presence of NaClO.
The clinical toxicology of sodium hypochlorite Slaughter, Robin J.; Watts, Martin; Vale, J. Allister ...
Clinical toxicology (Philadelphia, Pa.),
05/2019, Volume:
57, Issue:
5
Journal Article
Peer reviewed
Introduction: Sodium hypochlorite is used as a bleaching and disinfecting agent and is commonly found in household bleach.
Objective: The objective is to review critically the epidemiology, ...mechanisms of toxicity, clinical features, diagnosis, and management of hypochlorite poisoning.
Methods: PubMed was searched from January 1950 to June 2018 using the terms "Hypochlorite", "Sodium Hypochlorite", "Sodium Oxychloride", "Hypochlorous Acid", "Bleach", "Chlorine Bleach", in combination with the keywords "poisoning", "poison", "toxicity", "ingestion", "adverse effects", "overdose", and "intoxication". In addition, bibliographies of identified articles were screened for additional relevant studies including non-indexed reports. Non-peer-reviewed sources were also included. These searches produced 110 citations which were considered relevant.
Epidemiology: There is limited information regarding statistical trends on world-wide poisoning from sodium hypochlorite. In the United States of America, poison control center data have shown that enquiries regarding hypochlorite bleaches have ranged from 43,000 to 46,000 per year over the period 2012-2016.
Mechanisms of toxicity: Hypochlorite's potential to cause toxicity is related to its oxidizing capacity and the pH of the solution. Toxicity arises from its corrosive activity upon contact with mucous membranes and skin.
Features following ingestion: While small accidental ingestions are very unlikely to cause clinically significant toxicity, large ingestions may cause corrosive gastrointestinal injury and systemic effects, including metabolic acidosis, hypernatremia, and hyperchloremia.
Features following dental exposure: Hypochlorite is used extensively by dentists for cleaning root canals and is safe if the solution remains within the root canal. Extrusions into the periapical area can result in severe pain with localized large and diffuse swelling and hemorrhage.
Features following skin exposure: Prolonged or extensive exposure may cause skin irritation and damage to the skin or dermal hypersensitivity. Such exposures can result in either immediate or delayed-type skin reactions. High concentration solutions have caused severe chemical skin burns.
Features following inhalation: Although there are only limited data, inhalation of hypochlorite alone is likely to lead to no more than mild irritation of the upper airways.
Features following ocular exposure: Corneal injuries from ocular exposure are generally mild with burning discomfort and superficial disturbance of the corneal epithelium with recovery within 1 or 2 days. With higher concentration solutions, severe eye irritation can occur.
Diagnosis: The diagnosis can typically be made on the basis of a careful history, including details of the specific product used, its hypochlorite concentration, and the amount involved. As hypochlorite bleach produces a characteristic smell of chlorine, this may provide a diagnostic clue. In severe cases, corrosive injury is suggested on presentation because of hypersalivation, difficulty swallowing, retrosternal pain or hematemesis.
Management: Symptom-directed supportive care is the mainstay of management. Gastrointestinal decontamination is not beneficial. Local corrosive injury is the major focus of treatment in severe cases. Fiberoptic endoscopy and CT thorax/abdomen are complimentary and have been shown to be useful in corrosive injuries in assessing the severity of injury, risk of mortality and risk of subsequent stricture formation and should be performed as soon as possible after ingestion. Dental periapical extrusion injuries should be left open for some minutes to allow bleeding through the tooth and to limit hematoma development in tissue spaces. Once the bleeding has ceased, the canal can be dressed with non-setting calcium hydroxide and sealed coronally.
Conclusions: Accidental ingestion of household bleach is not normally of clinical significance. However, those who ingest a large amount of a dilute formulation or a high concentration preparation can develop severe, and rarely fatal, corrosive injury so prompt supportive care is essential as there is no specific antidote. Treatment primarily consists of symptom-directed supportive care.
This case report reviews the effect of combining a 250-cc bottle of standard antimicrobial, buffered sodium hypochlorite with a surgical method, low-pressure jet lavage irrigation in the outpatient ...setting to control difficult wound contamination. A 73-year-old man had been in treatment for over 8 years, undergoing at least 18 surgical wound debridement procedures for an extensive undermined pelvic pressure injury involving the sacrum, ischium, and greater trochanter. Cultures and polymerase chain reaction diagnostics revealed a multibacterial presence. Autofluorescent imaging (AFI) was used in 21 examinations performed after a 72-hour delay over a long weekend. The AFI contamination exceeded log 4 colony-forming units/g of tissue in all pretreatment examinations and was reduced to less than log 2 colony-forming units in 6 of 21 examinations, with the remaining 15 showing an estimated 80% or higher removal of the bacterial porphyrin "red" appearance. A total of 54 AFI examinations were performed using the combination treatment, and no adverse reactions were encountered. Treatment paradigms can be improved with a multifactorial approach.
In this study, Fe(Ⅱ)/peracetic acid (PAA) and Fe(Ⅱ)/sodium hypochlorite (NaClO) systems were applied as the combined preoxidation and coagulation process to enhance algae removal. A high removal rate ...of algae and turbidity could be achieved, with most algal cells keeping intact when adding reasonable concentrations of PAA and NaClO to enhance Fe(Ⅱ) coagulation. The variations of chlorophyll a, malondialdehyde, and intracellular reactive oxygen species suggested that moderate oxidation with only destroying surface-adsorbed organic matter rather than cell integrity was realized. The generated organic radicals, Fe(Ⅳ), and hydroxy radical played the major roles in the Fe(Ⅱ)/PAA system for the moderate oxidation of algal cells, but direct oxidation by NaClO rather than producing reactive species in the Fe(Ⅱ)/NaClO process contributed to the preoxidation. Concurrently, the in-situ formed Fe(Ⅲ) greatly promoted the agglomerating and settling of algae. The analysis of cell integrity, biochemical compositions, and fluorescence excitation-emission matrices spectra demonstrated that excess NaClO but not PAA would seriously damage the algal cells. This might be because that NaClO would directly oxidize the cell wall/membrane, while PAA mainly permeates into the cell to inactivate algae. These results suggest that Fe(Ⅱ)/PAA is an efficient strategy for algae-laden water treatment without serious algae lysis.
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•PAA and NaClO effectively enhanced Fe(Ⅱ) coagulation with PAA being better.•Moderate oxidation and coagulation were achieved simultaneously.•Excess NaClO damaged algal cells severely, but PAA had little effect on algae.•RO•, Fe(Ⅳ) and HO• played major roles in the Fe(Ⅱ)/PAA process for preoxidation.•The in-situ formed Fe(Ⅲ) performed better than the pre-formed Fe(Ⅲ).
Abstract Introduction Intracanal disinfection is a crucial step in regenerative endodontic procedures. Most published cases suggest the use of sodium hypochlorite (NaOCl) as the primary irrigant. ...However, the effect of clinically used concentrations of NaOCl on the survival and differentiation of stem cells is largely unknown. In this study, we tested the effect of various concentrations of NaOCl on the stem cells of the apical papilla (SCAPs) survival and dentin sialophosphoprotein (DSPP) expression. Methods Standardized root canals were created in extracted human teeth and irrigated with NaOCl (0.5%, 1.5%, 3%, or 6%) followed by 17% EDTA or sterile saline. SCAPs in a hyaluronic acid–based scaffold were seeded into the canals and cultured for 7 days. Next, viable cells were quantified using a luminescence assay, and DSPP expression was evaluated using quantitative real-time polymerase chain reaction. Results There was a significant reduction in survival and DSPP expression in the group treated with 6% NaOCl compared with the untreated control group. Comparable survival was observed in the groups treated with the lower concentrations of NaOCl, but greater DSPP expression was observed in the 1.5% NaOCl group. In addition, 17% EDTA resulted in increased survival and DSPP expression partially reversing the deleterious effects of NaOCl. Conclusions Collectively, the results suggest that dentin conditioning with high concentrations of NaOCl has a profound negative effect on the survival and differentiation of SCAPs. However, this effect can be prevented with the use of 1.5% NaOCl followed by 17% EDTA. The inclusion of this irrigation regimen might be beneficial in regenerative endodontic procedures.
To evaluate the antimicrobial activity of Triton irrigation versus 4% sodium hypochlorite (NaOCl) utilizing a direct contact test and an extracted tooth model.
In the first experiment, a direct ...contact test was conducted to compare bacterial DNA removal and microbial diversity changes following irrigation with 4% NaOCl or Triton. Hydroxyapatite and dentin discs were inoculated with subgingival human-derived dental plaque for 2 weeks utilizing the Center for Disease Control biofilm reactor and subsequently challenged with the root canal irrigants for 5 minutes. In the second experiment, teeth contaminated with a multispecies biofilm (n = 24) were assigned into two treatment groups, NaOCl or Triton irrigation. Samples were obtained for quantitative real-time polymerase chain reaction and next-generation sequencing analysis before and after instrumentation. The Shannon and Chao1 indices were used to measure alpha diversity. The Bray–Curtis dissimilarity and ANOSIM was used to measure beta diversity. Differences in abundances of genera were evaluated using Kruskal–Wallis test with Bonferroni corrections.
The direct contact test revealed no significant differences in the bacterial load based on 16S rRNA gene molecules/μL, reads, or differences in the Shannon index among groups. In the extracted tooth model, a bacterial load reduction of log10 3.08 ± 0.69 and 2.76 ± 0.91 were found for NaOCl and Triton, respectively (P = .348). Next-generation sequencing showed fewer reads, lower Chao1, and beta diversity values when pretreatment and post-treatment samples were assessed in both experimental groups (P < .0001). The Kruskal–Wallis analysis found that 17 genera of bacteria were over-represented in minimal values in the Triton post-treatment group, 14 of these genera represented less than 1% of the microbial community.
Both irrigants had limited antimicrobial activity in the direct contact test. When used in conjunction with mechanical instrumentation both irrigants were able to reduce the bacterial DNA load and diversity in comparison with pretreatment communities. The NaOCl irrigation, followed by ethylenediaminetetraacetic acid flush, was more effective in decreasing DNA counts from low-abundance organisms.
•Oxidized starches are used in both food and non-food industries.•Sodium hypochlorite and hydrogen peroxide are the most common oxidizing agents.•Ozone in gaseous or aqueous phase is considered a ...clean technology.•Starch source and reaction conditions affect the properties of oxidized starches.•Depolymerization and/or crosslinking of starch polymers occurs due to oxidation.
During oxidation, the hydroxyl groups of starch molecules are first oxidized to carbonyl groups, then to carboxyl groups. The contents of the carbonyl and carboxyl groups in a starch molecule therefore indicate the extent of starch oxidation. The mechanisms of starch oxidation with different oxidizing agents, including sodium hypochlorite, hydrogen peroxide, ozone and sodium periodate, are described in this review. The effects of these oxidizing agents on the molecular, physicochemical, thermal, pasting and morphological properties of starch are described as well. In addition, the main industrial applications of oxidized starches are presented. The present review is important for understanding the effects of oxidation on starch properties, and this information may facilitate the development of novel oxidized starches for both food and non-food applications.
In the removal of nitric oxide (NO) by sodium chlorite (NaClOsub.2), the NaClOsub.2 concentration is usually increased, and an alkaline absorbent is added to improve the NO removal efficiency. ...However, this increases the cost of denitrification. This study is the first to use hydrodynamic cavitation (HC) combined with NaClOsub.2 for wet denitrification. Under optimal experimental conditions, when 3.0 L of NaClOsub.2 with a concentration of 1.00 mmol/L was used to treat NO (concentration: 1000 ppmv and flow rate: 1.0 L/min), 100% of nitrogen oxides (NOsub.x) could be removed in 8.22 min. Furthermore, the NO removal efficiency remained at 100% over the next 6.92 min. Furthermore, the formation of ClOsub.2 by NaClOsub.2 is affected by pH. The initial NOsub.x removal efficiency was 84.8-54.8% for initial pH = 4.00-7.00. The initial NOsub.x removal efficiency increases as the initial pH decreases. When the initial pH was 3.50, the initial NOsub.x removal efficiency reached 100% under the synergistic effect of HC. Therefore, this method enhances the oxidation capacity of NaClOsub.2 through HC, realizes high-efficiency denitrification with low NaClOsub.2 concentration (1.00 mmol/L), and has better practicability for the treatment of NOsub.x from ships.
Sodium hypochlorite (NaOCl) is one of the most commonly used irrigant because of its several advantages. However, it is highly cytotoxic and can lead to severe tissue damage. NaOCl accident occurs ...when it is extruded beyond root confines into periapical or periradicular tissues. It is an irrigant mishap which can be life threatening and/or cause residual or long term or permanent consequences with malpractice and medico-legal implications. There are many factors which can influence the occurrence and progress of NaOCl accident. These factors can be broadly categorized as patient (host)-, tooth-, operator-, and NaOCl-related factors. They can be further categorized as predisposing and extent factors. It is vital for a clinician to thoroughly understand and identify various influencing factors to prevent NaOCl accident with its associated consequences including any potential medico-legal issues. The purpose of this article is to provide a narrative review on various factors which predispose to the occurrence of NaOCl accident and influence its extent and/or outcome.
