Impact of different activation procedures on sodium hypochlorite penetration into dentinal tubules after endodontic retreatment via confocal laser scanning microscopy.

BACKGROUND: Infected dentinal tubules are a possible source of bacteria that are responsible for the failure of root canal treatment. Therefore, disinfection of dentinal tubules by increasing the penetration of the irrigation solution is important for success in retreatment cases. This study utilized confocal laser scanning microscopy (CLSM) to assess and compare the impact of XPR, ultrasonic irrigation (UI) and sonic activation (SA) on NaOCl penetration into dentinal tubules following endodontic retreatment. METHODS: A total of forty mandibular premolars were enrolled in this investigation. Following root canal preparation up to ProTaper X3 file (30/0.07), root canals were obturated with gutta-percha and bioceramic root canal sealer with single cone technique. The root canal filling materials were removed using ProTaper nickel-titanium rotary retreatment files until the working length was reached. The retreatment procedure was finalized using the ProTaper Next X4 (40/0.06). The teeth were divided into four groups based on the irrigation activation technique: control (conventional needle irrigation), SA, UI and XPR. During the final irrigation procedure, Rhodamine B dye was introduced to 5% NaOCl for visualization via CLSM. Subsequent to image acquisition, the maximum penetration, penetration percentage, and penetration area were calculated. Data were statistically analyzed using the Kruskal-Wallis, Friedman, and Bonferroni Dunn multiple comparison tests through R software (p < 0.05). RESULTS: In the middle third, UI yielded a significantly higher penetration percentage than the control group (p < 0.05). The UI and XPR groups showed increased penetration percentages in the coronal and middle thirds compared with the apical third (P < 0.05). Maximum penetration was notably reduced in the apical third than in comparison with the coronal and middle thirds in all groups (p < 0.05). In the control, SA and XP groups, the penetration area was ranked in descending order as coronal, middle and apical (p < 0.05). Conversely, in the ultrasonic group, the penetration area was significantly lower in the apical third than in the middle and coronal thirds (p < 0.05). CONCLUSIONS: UI enhanced the penetration percentage in the middle third of the root compared with that in the control group. XPR and SA showed no significant effect on NaOCl penetration following retreatment.

Effectiveness of supplementary antimicrobial procedures in disinfecting lateral canals as evaluated by a novel ex vivo analytical approach.

This ex vivo study devised an analytical ex vivo method for infection/disinfection of simulated lateral canals located in the middle and apical segments of the root. The antibacterial effects of supplementary approaches were tested in this model. Extracted mandibular premolars had their main root canals enlarged and then two lateral canals (100 µm in diameter) were created in the root, one in the apical and the other in the middle portion. Micro-computed tomography was used for specimen selection and to confirm the quality of the simulated ramifications. The specimens were contaminated with a mixed bacterial culture from subgingival bacterial biofilm added to pure Enterococcus faecalis strain ATCC 29212 grown overnight, using special strategies to facilitate culture medium penetration within the lateral canals. The following procedures were tested for disinfection: NaOCl/passive ultrasonic irrigation (PUI), NaOCl/XP-endo Finisher, ozonated water/continuous ultrasonic irrigation (CUI), and NaOCl/conventional irrigation with 30-G needles (control). Bacteriological samples were taken from the main canal before (S1) and after (S2) each supplementary protocol, and also from each lateral canal after treatment (S3). DNA extracted from the samples was subjected to quantitative real-time polymerase chain reaction. All S1 main canal samples were positive for bacterial presence. Bacterial counts in the main root canal substantially decreased by 99.2% after PUI, 99.1% after ozone/CUI, 99% after XP-endo Finisher, and 96% in the control group (P < 0.01 for all groups). There were no significant differences between groups (P > 0.05). The same was observed when comparing the effects of the supplementary approaches in the apical and middle lateral canals (P > 0.05). Only a few lateral canals showed no detectable bacteria. The method proposed here proved effective for ex vivo infection/disinfection studies. All supplementary approaches induced a substantial bacterial reduction in the main canal, with no significant differences between them. However, in terms of lateral canal disinfection, none of the tested approaches showed significant effects when compared to the control group.

Reactive Oxygen Species Mediate the Bactericidal Activity of Chlorine Against Salmonella.

Chlorine and its derivatives have been used as an antibacterial agent to reduce Salmonella contamination in poultry meat during processing. We evaluated the survival of 4 different Salmonella serotypes (Typhimurium, Enteritidis, Heidelberg, and Gaminara) in the presence of 50 ppm sodium hypochlorite (NaOCl) alone or with the addition of thiourea (radical scavenger) or Dip (iron chelator) to determine the contribution of reactive oxygen species (ROS) in the bactericidal activity of NaOCl. The result showed that for all four serotypes the addition of thiourea or Dip significantly increased the % survival as compared to the respective NaOCl treatment groups, while it was significantly higher with thiourea as compared to Dip (P < 0.05). We also evaluated the survival of 11 deletion mutants of S. Typhimurium, which were demonstrated to increase (∆atpC, ∆cyoA, ∆gnd, ∆nuoG, ∆pta, ∆sdhC, and ∆zwf) or decrease the production of ROS (∆edd, ∆fumB, ∆pykA, and ∆tktB) in Escherichia coli (E. coli), in the presence of 50 ppm. The results showed that only two (∆sdhC and ∆zwf) out of 7 ROS-increasing mutants showed reduced % survival as compared to the wild-type (P < 0.05), while all four deletion ROS-decreasing mutants showed significantly higher % survival as compared to the wild-type (P < 0.05). This work suggests that the production of ROS is a major component of the bactericidal activity of NaOCl against Salmonella serotypes and there might be a significant difference in the metabolic pathways involved in ROS production between Salmonella and E. coli.

Phenotypic and genotypic determination of resistance to common disinfectants among strains of Acinetobacter baumannii producing and non-producing biofilm isolated from Iran.

BACKGROUND: Nosocomial infections are a global problem in hospitals all around the world. It is considered a major health problem, especially in developing countries. The increase in the patient's stay in hospitals has increased the mortality rate, and consequently, the costs drastically increase. The main purpose of using disinfectants in the hospital environment is to reduce the risk of nosocomial infections. Ethylene diamine tetra acetic acid (EDTA) causes lysis and increases susceptibility to antimicrobial agents in the planktonic form of bacteria. This substance affects the permeability of the outer membrane of bacteria. It also prevents the formation of biofilms by bacteria. MATERIALS AND METHODS: In the current study, 120 isolates of Acinetobacter baumannii (A. baumannii) were confirmed by phenotypic and genotypic methods. Antibiogram was performed and then the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of isolates against 5% sodium hypochlorite, ethanol %70, sayasept-HP 2%, chlorhexidine 2%, dettol 4/8% were evaluated. In addition, the disinfectant effect was re-evaluated with the mixture of EDTA solution. All isolates were examined for biofilm presence by crystal violet staining method in triplicates and repeated three times for each strain. Also for all isolates detection of efflux pump genes (Qac-E, qacE-Δ1, SUG-E) by PCR technique was done. RESULTS: Antibiogram results of A. baumannii showed that 6.7% were Multi-drug-resistant (MDR), and 89.2% were Extensively drug-resistant (XDR) isolates. The highest effect of disinfectants was related to 5% sodium hypochlorite, and the least effect was 70% ethanol. EDTA increases the efficacy of selected disinfectants significantly. The highest prevalence of the efflux pump genes was related to SUG-E (95%) and Qac-E (91.7%), and, the qacE-Δ1 gene with 12.5%. The biofilm production rate was 91.3% among all isolates. CONCLUSION: The best and safest way to disinfect hospital floors and surfaces is to choose the right disinfectants, and learn how to use them properly. In this study, a mixture of disinfectants and EDTA had a significant effect on bactericidal activity. it was found that improper use of disinfectants, especially the use of sub-inhibitory dilutions, increases the resistance of bacteria to disinfectants.

Evaluation of pulp tissue dissolving efficiency of sodium and calcium hypochlorite solutions activated by ultrasonics and laser: an in vitro study.

OBJECTIVES: This study aimed to compare the tissue dissolving capacities of sodium and calcium hypochlorite [NaOCl and Ca(OCl)2] solutions applied without activation or with two irrigant activation methods. MATERIALS AND METHODS: One hundred and eight dentin cavities were prepared. Preweighed tissue pieces were placed in these dentin cavities, and samples were divided into nine groups of twelve. In groups 1, 2, and 3, NaOCl was used with non-activation (NA), passive ultrasonic (PUA), and laser activation (LA). With the same techniques, Ca(OCl)2 was used in groups 4, 5, and 6, and distilled water was used in groups 7, 8, and 9. The weight loss of tissue samples was calculated and analyzed using Two-way ANOVA and Duncan tests. RESULTS: Distilled water groups showed no tissue dissolution in any conditions. NaOCI and Ca(OCI)2 showed statistically similar dissolving effectiveness when used with the same technique. Activated groups dissolved significantly greater tissue than non-activated ones, the highest in LA. CONCLUSIONS: Ca(OCI)2 can be an alternative to NaOCl; for both, the first choice of activation may be the LA.

Effect of Active Oxygen Fluid (Blue®m) as a Root Canal Irrigant Against Enterococcus Faecalis.

PURPOSE: To evaluate the antimicrobial effect of a new active oxygen fluid (Blue®m) as a root canal irrigant against Enterococcus faecalis compared to sodium hypochlorite (NaOCl). MATERIAL AND METHODS: Forty-five extracted single-canaled human teeth were selected, received root canal preparation, autoclaved, and contaminated with Enterococcus faecalis. The specimens were randomly allocated into three groups: Group (A) served as the negative control, receiving irrigation with saline (n = 15); Group (B) was irrigated with 5.25% NaOCl (n = 15); and Group (C) was irrigated with 10 mL of Blue®m (n = 15). Microbial sampling from the root canals was performed before and after irrigation. The difference between the pre-irrigation and post-irrigation colony-forming units (CFU/mL) was calculated. The data was analysed using a one-way ANOVA followed by post-hoc Tukey tests. The significance level was set at 5%. RESULTS: Blue®m statistically significantly reduced the bacterial load compared to saline (p = 0.009), but NaOCl was most effective, outperforming both (p 0.0001). CONCLUSION: Irrigation with Blue®m demonstrated antibacterial efficacy against Enterococcus faecalis, but it was not as effective as NaOCl.

Evaluation of the long-term protection conferred by an organosilicon-based disinfectant formulation against bacterial contamination of surfaces.

AIMS: The aim of this work was to evaluate the efficacy of an organosilicon-based, commercially available antimicrobial formulation in the My-shield® product line against bacterial surface contamination. METHODS AND RESULTS: The antimicrobial product was tested in vitro for its long-term persistence on surfaces and effectiveness against Staphylococcus aureus biofilms in comparison to 70% ethanol and 0.1% or 0.6% sodium hypochlorite. Field testing was also conducted over 6 weeks at a university athletic facility. In vitro studies demonstrated the log reductions achieved by the test product, 70% ethanol, and 0.1% sodium hypochlorite were 3.6, 3.1, and 3.2, respectively. The test product persisted on surfaces after washing and scrubbing, and pre-treatment with this product prevented S. aureus surface colonization for up to 30 days. In comparison, pre-treatment with 70% ethanol or 0.6% sodium hypochlorite was not protective against S. aureus biofilm formation after seven days. The field test demonstrated that weekly applications of the test product were more effective at reducing surface bacterial load than daily applications of a control product. CONCLUSIONS: The test product conferred greater long-term protection against bacterial growth and biofilm formation by S. aureus than ethanol and sodium hypochlorite. Even with less frequent applications, the test product maintained a high level of antimicrobial activity.

Normal Saline or Sodium Hypochlorite Irrigation for Vital Pulp Therapy? A Non-Inferiority Randomized Controlled Trial.

criteria were randomized to each irrigant, 65 in the NaOCl and 60 in the NSS groups. ProRoot® MTA was used as a pulp dressing material in both groups and teeth were followed for 12 months. The primary outcome was the success of VPT; requiring both clinical and radiographic success to be considered as success. The hypothesis was that the absolute difference of VPT success in the NSS group was not worse than that in the NaOCl group, by a margin of 5%. The secondary outcome was discoloration; percentages of discolorations between both groups were compared. Results: Using a per protocol analysis, the absolute difference of VPT success between the NSS and NaOCl groups was 2.08% (95% CI: -1.95, 6.1). Perceptible gray discolorations were 80% and 63% in NaOCl and NSS groups (difference -17%; 95% CI: -40.0, 6.2; p=0.15). Conclusions: For MTA-VPT procedure, irrigation with NSS was not worse than that with NaOCl. However, both irrigants caused discoloration. (EEJ-2023-05-065).

The effect of different intracanal irrigants on the push-out bond strength of dentin in damaged anterior primary teeth.

This experimental study investigated the effect of different intracanal irrigants on the push-out bond strength of dentin in damaged anterior primary teeth. The crowns of 90 anterior primary teeth were sectioned horizontally, 1 mm above the cementoenamel junction (CEJ). Following canal preparation with K-files, all groups except the negative control received normal saline irrigation. Canals were then irrigated with either 3% or 5.25% sodium hypochlorite (NaOCl), 2% or 0.2% chlorhexidine (CHX) solution (except negative and positive controls). The roots were filled with Metapex material and covered with a calcium hydroxide liner. In root canals, the bond was applied by self-etching and then light-cured for 20 seconds before canals were restored incrementally with composite. Stereomicroscopes were used to assess failure patterns. Push-out bond strengths (MPa ± SD) were: 3% NaOCl (16.92 ± 5.78), 5.25% NaOCl (8.96 ± 3.55), 2% CHX (14.76 ± 5.56), and 0.2% CHX (7.76 ± 2.93). Significant differences were seen across the irrigants regarding the push-out bond strength of dentin sections (P <0.001). The most frequent failures were adhesive and cohesive. NaOCl and CHX irrigants increased the push-out bond strength compared to controls. Compared to controls, both 3% NaOCl and 2% CHX irrigants significantly increased the push-out bond strength of dentin in non-vital anterior primary teeth.

Effectiveness of white tea-mediated silver nanoparticles as an intracanal irrigant against Enterococcus faecalis: An in vitro study.

BACKGROUND: The probability of a positive outcome of root canal therapy is substantially higher if the infection is eradicated successfully before the obturation of the root canal system. Irrigation is an essential aspect of root canal debridement, as it enables more thorough cleaning than is possible with root canal instrumentation alone. To overcome the side effects of chemical irrigants, there has been a search for herbal medicines as substitutes. OBJECTIVES: The aim of the present study was to explore the antimicrobial efficacy of white tea-mediated silver nanoparticles (AgNPs) formulated as an intracanal irrigant against Enterococcus faecalis, and to compare it with the efficacy of chlorhexidine and sodium hypochlorite irrigants. MATERIAL AND METHODS: The experimental groups were as follows: group I - white tea-mediated AgNPs; group II - 2% chlorhexidine; and group III - 2.5% sodium hypochlorite. The characterization of AgNPs was performed using ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM) analysis. Enterococcus faecalis was inoculated onto Mueller-Hinton agar plates. The disks impregnated with irrigants were placed on the inoculated plates and incubated aerobically at 37°C for 24 h. Then, the growth inhibition zones were measured. Statistical analysis was performed using the one-way analysis of variance (ANOVA) and the post hoc tests. RESULTS: A concentration of 50 µL of white tea-mediated AgNPs exhibited the greatest zone of inhibition (32 ±2 mm), followed by 2% chlorhexidine (25 ±1 mm) and 2.5% sodium hypochlorite (23 ±3 mm). CONCLUSIONS: White tea-mediated AgNPs showed promising results in the elimination of E. faecalis, being superior to chlorhexidine and sodium hypochlorite irrigants.

The effect of final irrigation with different solutions on smear layer removal and dentin erosion: A scanning electron microscope study.

AIM: This study aimed to compare the effectiveness of initial irrigation with sodium hypochlorite (NaOCl) and final irrigation with QMix, 40% citric acid, and 17% ethylenediaminetetraacetic acid (EDTA) on smear layer removal and dentin erosion. METHODOLOGY: Forty extracted human mandibular premolar teeth were randomly divided into four groups (n = 10) according to the type of final irrigants used: 17% EDTA, QMix, citric acid, and control (normal saline). Canals were mechanically prepared using ProTaper Next instruments to an apical size of X3. Subsequently, the roots were sectioned in a buccolingual direction. Scanning electron microscopy (SEM) was used to assess the presence of the smear layer and the amount of dentin erosion in the coronal, middle, and apical thirds of the root canals. RESULTS: In regards to smear layer removal, there was a significant difference between the control group and the other tested groups. Moreover, it was significantly higher in the coronal and middle thirds than in the apical third. However, there were no significant differences between the groups of EDTA, QMix, and citric acid. Concerning dentin erosion, citric acid produced significantly more dentin erosion than the other tested groups. CONCLUSION: Final irrigation with solutions had a higher ability to remove the smear layer in the coronal and middle thirds compared to the apical third. Of all the solutions tested, 40% citric acid had the most pronounced impact on dentin erosion, followed by 17% EDTA and QMix.

Effect of disinfectants on multispecies biofilm, the physical and mechanical properties of polymethyl methacrylate, and the corrosion of cobalt chromium alloy.

STATEMENT OF PROBLEM: The optimal disinfection protocol that controls adverse effects and promotes effective antimicrobial action on removable prostheses is unclear. PURPOSE: This in vitro study investigated the effect of disinfectant solutions on the biological, physical, mechanical, and chemical properties of removable prosthesis materials. MATERIAL AND METHODS: Specimens of polymethyl methacrylate (PMMA) and cobalt chromium (Co-Cr) alloy were immersed in distilled water (PMMA) or artificial saliva (Co-Cr) as the control and in 0.25% sodium hypochlorite (NaOCl0.25%), 0.5% chloramine T (CT0.5%), and 0.15% Triclosan (TR0.15%). The antibiofilm activity was evaluated by microbial load and cell metabolisms of the mixed biofilm. Physical (color change, sorption, solubility, and surface roughness), mechanical (hardness, flexural, and impact strength), and chemical (corrosion) properties were analyzed before and after simulating a 5-year immersion. Laser confocal microscopy, scanning electron microscopy (SEM), and dispersive energy spectroscopy (EDS) complemented the analyses. The data were analyzed by using the Mann-Whitney U test, Kruskal-Wallis with Dunn posttests, 1-way ANOVA, and repeated measures ANOVA (α=.05). RESULTS: All solutions were effective against bacteria, but only NaOCl0.25% eliminated Candida spp. TR0.15%, and CT0.5% increased cell metabolisms. For interaction (time and solution), there was a reduction in PMMA hardness in the control and TR0.15%. Color, sorption, solubility, and flexural strength did not change. CT0.5% and TR0.15% were similar for impact resistance. CT0.5% caused the lowest roughness. NaOCl0.25% showed the greatest corrosive potential. Dark spots were seen under SEM in Co-Cr stored with NaOCl0.25% and TR0.15%. EDS indicated different proportions of oxygen, cobalt, chromium, and molybdenum. CONCLUSIONS: NaOCl0.25% had the best antimicrobial action. CT0.5% and TR0.15% have potential. Hardness and roughness changes were clinically acceptable, and the other properties remained unchanged. All the solutions caused color changes. NaOCl0.25% was unsatisfactory for use with Co-Cr, CT0.5% was intermediate, and TR0.15% was suitable.

Effect of continuous vs sequential chelation on the mechanical properties of root dentin: An ex vivo study.

OBJECTIVES: To evaluate the mechanical properties of root canal dentin treated with sodium hypochlorite (NaOCl) in combination with hydroxyethylidene diphosphonic acid (HEDP) or ethylenediaminetetraacetic acid (EDTA). METHODS: For testing fracture resistance, 45 single-rooted teeth were instrumented and irrigated with NaOCl/HEDP, NaOCl/EDTA, or distilled water. Fifteen untreated teeth served as control. After obturation, specimens from the experimental groups were thermocycled, dynamically-loaded, and then statically-loaded in a universal testing machine until failure. For flexural strength analysis, 15 teeth were instrumented and irrigated with NaOCl/HEDP or NaOCl/EDTA. Root segments were sectioned into dentin bars and tested for flexural strength using a universal testing machine. For microhardness evaluation, 20 teeth were instrumented and irrigated with NaOCl/HEDP or NaOCl/EDTA. Dentin disks from the coronal-third of each root segment were prepared, one before and one after irrigation, for microhardness testing with a Knoop hardness tester. RESULTS: The highest fracture resistance was recorded in the untreated group, and the lowest in the EDTA group. Although the HEDP group had higher fracture resistance than the EDTA group, the distilled water group demonstrated even greater fracture resistance than the HEDP group. Specimens treated with HEDP had significantly higher flexural strength and microhardness values when compared with those treated with EDTA. CONCLUSION: The fracture resistance, flexural strength, and microhardness of root canal dentin were higher when root canals were irrigated with NaOCl/HEDP, when compared with NaOCl/EDTA. CLINICAL SIGNIFICANCE: Irrigating root canals with NaOCl combined with HEDP significantly improves the mechanical integrity of root canal dentin compared to the use of NaOCl with EDTA.

Regulation of curcumin reductase curA (PA2197) through sodium hypochlorite and N-ethylmaleimide sensing by TetR family repressor CurR (PA2196) in Pseudomonas aeruginosa.

Pseudomonas aeruginosa PA2196 is a TetR family transcriptional repressor. In this study, the deletion of the PA2196 gene caused increased expression of the downstream gene curA (PA2197), which encodes for a NADPH-dependent curcumin/dihydrocurcumin reductase. The PA2196 gene was then identified as curR, and a DNA footprinting assay showed that CurR directly bound to the curA promoter at an imperfect 15-bp inverted repeat, 5'-TAGTTGA-C-TGGTCTA-3'. A curA promoter-lacZ fusion assay and site-directed mutagenesis further demonstrated that the identified CurR binding site plays a crucial role in curA repression by CurR. curA transcription was inducible by sodium hypochlorite (NaOCl) and N-ethylmaleimide (NEM) but not by hydrogen peroxide, organic hydroperoxide, or curcumin. The oxidation and alkylation of CurR by NaOCl and NEM, respectively, resulted in the inactivation of its DNA-binding activity, which induced curA expression. Under the tested conditions, the deletion of either curR or curA did not affect the survival of P. aeruginosa under NaOCl stress in the absence or presence of curcumin.

Assessing the efficacy of sanitizer sprays during brush or polyvinyl chloride (PVC) roller treatment to reduce Salmonella populations on whole mangoes.

Sanitizer spray and brush roller treatments have been documented as an effective means of reducing Salmonella on the surface of produce. The purpose of this study was to evaluate the efficacy of chlorine (NaOCl), peroxyacetic acid (PAA), and chlorine dioxide (ClO2) sprays to reduce Salmonella populations on the surface of mangoes during washing with brush or polyvinyl chloride (PVC) rollers. Whole mangoes were spot inoculated with 100 µL of a rifampicin-resistant Salmonella (8 log CFU/mL) cocktail at the equator and dried for 1 h. Mangoes were washed with a lab-scale roller system with either ground water (control), or sanitizers (100 ppm NaOCl, 80 ppm PAA, or 5 ppm ClO2) for 0, 5, 15, 30, or 60 s (n = 15 mangoes). Dey/Engley buffer (100 mL) was used to rinse mangoes before plating on media supplemented with rifampicin. NaOCl, PAA, and ClO2 spray (except for ClO2 at 30 s) had significantly higher reduction on Salmonella population than water spray at all treatment times (P ≤ 0.05) when brush rollers were used. All tested sanitizers also achieved a significantly higher reduction than water at 5 s when PVC rollers were used (P ≤ 0.05). Salmonella reductions achieved by brush and PVC rollers was not statistically different (P > 0.05). After a 5 s treatment on brush and PVC rollers, NaOCl, PAA, and ClO2 spray had ca. 3.03 and 3.45 log, 3.96 and 3.28 log, and 2.54 and 2.00 log CFU/mango reductions, respectively, whereas water spray achieved 1.75 and 0.98 log CFU/mango reduction. Addition of sanitizers to spray water used during brush or PVC washing in mango packinghouses can reduce Salmonella on mango surfaces.

Comparative evaluation of selected concentrations of sodium hypochlorite on the outcome of endodontic therapy among Ghanaians.

BACKGROUND: Endodontic treatment is one of the main dental treatments to manage inflamed or infected root canal systems of teeth. The success of endodontic treatment principally depends on eradicating microorganisms in the root canal by chemo-mechanical debridement with irrigation solutions like sodium hypochlorite (NaOCl). NaOCl has been used in concentrations ranging from 0.5% to 5.25%. This study determined the antimicrobial effectiveness of selected concentrations (0.5%, 1.0%, 2.6%, and 5.2%) of NaOCl in endodontic treatment. METHODS: The study sites were the University of Ghana Dental School (UGDS) and Noguchi Memorial Institute for Medical Research (NMIMR). Sixty infected single-rooted single-canal teeth were used. Before (S1) and after (S2), root canal samples during the endodontic treatment with the selected concentrations of NaOCl were examined via anaerobic and aerobic cultures. The isolates were identified using Matrix Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry (MALDI-TOF MS). RESULTS: All S1 samples were positive for cultivable bacteria. Fifty-three (53) different microbial species belonging to 20 different microbial genera were isolated. Streptococcus viridans was the most frequently isolated microbe. There were zero isolates in the root canals irrigated with 2.6% and 5.2% NaOCl. Two teeth had isolates in the groups irrigated with the lower concentrations (0.5% and 1.0%) of NaOCl. The persistent bacteria were one species each of Streptococcus mitis and Streptococcus oralis, respectively. CONCLUSION: Root canal treatments using chemo-mechanical preparation with the selected concentrations (0.5%, 1.0%, 2.6%, and 5.2%) of NaOCl were effective in significantly reducing the microbial load, and for the 5.2% and 2.6% concentrations, in eliminating all the microorganisms.

Effect of herbal irrigants on surface roughness of intraradicular dentin using quantitative method of 3D surface texture analysis.

Replacing the conventional endodontic irrigants with herbal agents could avoid complications associated with using sodium hypochlorite (NaOCl). Endodontic irrigants alter the surface roughness of the dentinal wall surface, which affects sealer mechanical retention. This study aimed to assess the effect of experimental herbal Moringa oleifera and orange peel extract irrigant on intraradicular dentin (IRD) surface roughness using quantitative 3D surface analysis by scanning electron microscopy (SEM) regarding the smear layer assessment. Sixty human root sections were divided into four groups (n = 15): NaOCl combined with 17% ethylenediaminetetraacetic acid (EDTA); negative control (saline); moringa extract (MO); and orange oil (OO). SEM images were assessed quantitatively for surface roughness (Ra) in the coronal, middle, and apical IRD. The data were analysed by Kruskal-Wallis, Friedman, and Dunn's tests. All groups showed statistically significant differences (P = 0.007). MO exhibited significantly greater Ra values at the coronal, middle, and apical root levels than OO (P = 0.007, 0.009, and 0.046, respectively). There was no significant change in Ra values at various root levels within each group at P = 0.091, 0.819, 0.819, and 0.549 for the EDTA, saline, MO, and OO groups. Considerable (IRD) surface roughness analysis makes Moringa extract a promising herbal endodontic irrigant alternative to the NaOCl plus EDTA regimen.

Susceptibility of pESI positive Salmonella to treatment with biocide chemicals approved for use in poultry meat processing as compared to Salmonella without the pESI plasmid.

Salmonella is a common cause of human foodborne illness, which is frequently associated with consumption of contaminated or undercooked poultry meat. Serotype Infantis is among the most common serotypes isolated from poultry meat products globally. Isolates of serotype Infantis carrying the pESI plasmid, the most dominant strain of Infantis, have been shown to exhibit oxidizer tolerance. Therefore, 16 strains of Salmonella with and without pESI carriage were investigated for susceptibility to biocide chemical processing aids approved for use in US poultry meat processing: peracetic acid (PAA), cetylpyridinium chloride (CPC), calcium hypochlorite, and sodium hypochlorite. Strains were exposed for 15 s to simulate spray application and 90 min to simulate application in an immersion chiller. All strains tested were susceptible to all concentrations of PAA, CPC, and sodium hypochlorite when applied for 90 min. When CPC, calcium hypochlorite, and sodium hypochlorite were applied for 15 s to simulate spray time, strains responded similarly to each other. However, strains responded variably to exposure to PAA. The variation was not statistically significant and appears unrelated to pESI carriage. Results highlight the necessity of testing biocide susceptibility in the presence of organic material and in relevant in situ applications.

The Use of Antimicrobial Washes to Inactivate Shiga Toxin-Producing Escherichia coli from In-Shell Pecans and Wash Water Contaminated by Different Inoculation Routes.

In-shell pecans are typically harvested after falling from trees to the ground, presenting a potential route of contamination of foodborne pathogens from soil contact. In-shell pecans are often subjected to various processing or washing steps prior to being shelled. This study determined Shiga toxin-producing Escherichia coli (STEC) reductions after treatment with antimicrobial washes on direct and soil-inoculated in-shell pecans and evaluated the cross-contamination potential of the spent pecan washes after treatment. Pecans were directly and soil-inoculated with an STEC cocktail (O157:H7, O157:NM, O121, O26). Direct inoculation was achieved by spraying the STEC cocktail on the pecans. For soil-inoculation pecans, autoclaved soil was sprayed with the STEC cocktail, homogenized for 2 min, and used to coat in-shell pecans. Inoculated pecans were washed in treatments of 2% lactic acid (LA), 1,000 ppm free chlorine (sodium hypochlorite; NaClO), hot water (HW; 85 ± 2 °C), or ambient water (C [control]; 18 ± 2 °C) for 2, 5, and 10 min and diluted to enumerate STEC populations. After treatments, 100 mL of the spent wash was vacuum filtered through a 0.45-µm membrane and plated on selective agar. HW significantly reduced STEC populations from pecans with and without soil regardless of treatment time (p < 0.05), NaClO reduced STEC populations more than the ambient control wash on directly inoculated pecans, but there were no significant differences between STEC reductions from ambient water (C), LA, and NaClO treatments on soil-inoculated pecans (p > 0.05). Larger STEC populations were enumerated from ambient water wash compared to the antimicrobial washes (p < 0.05). The HW, LA, and NaClO treatments were effective at maintaining the quality of the wash water, with STEC levels being generally at or below the detection limit (<1 CFU/100 mL), while HW was the most effective at reducing STEC from in-shell pecans with and without a soil coating (>5-log CFU/mL reductions).

Antimicrobial efficacy of DJK-5 peptide in combination with EDTA against biofilms in dentinal tubules: Primary irrigation, recovery and re-irrigation.

AIM: To investigate the dynamic recovery of biofilms within dentinal tubules after primary irrigation with different protocols, and to evaluate the efficacy of various re-irrigation protocols on recovered biofilm, considering factors such as smear layer, nutrient conditions, and primary irrigants. METHODOLOGY: A total of 416 mono or multi-species biofilms samples were prepared from human teeth and incubated for 3 weeks. After inducing a smear layer on half of the samples, all specimens were irrigated with one of the following irrigant sequences: (1) 6% NaOCl +17% EDTA, (2) 6% NaOCl +8.5% EDTA, (3) 6% NaOCl and (8.5% EDTA +10 µg/mL DJK-5 antimicrobial peptide), or (4) sterile water. Thirty-two samples were used to assess immediate effect, whilst the rest were re-incubated to assess biofilms recovery. Nutrient conditions were defined based on whether culture media were changed (nutrient-rich) or not (nutrient-poor) during re-incubation. After 16 weeks, recovered biofilms underwent re-irrigation using four additional protocols, with or without DJK-5 peptide, based on primary irrigants. Confocal laser scanning microscopy was employed to evaluate immediate irrigant effects, biofilms recovery intervals (1, 3, 5, 8, 12, and 16 weeks after primary irrigation), and re-irrigation effects at the 16-week. Statistical analysis included one-way anova and two-way mixed anova tests. RESULTS: The DJK-5 peptide irrigation protocols demonstrated the highest killing rates during primary irrigation and resulted in a longer biofilms recovery time of 16 weeks compared to non-peptide protocols (p < .001). Both primary irrigation type and smear layer presence significantly influenced biofilms recovery (p < .001). In the absence of smear layer, re-irrigation efficacy didn't significantly differ from primary irrigation, regardless of primary irrigation type or nutrient conditions. However, with a smear layer present, re-irrigation led to significantly higher proportion of dead bacteria compared to primary irrigation (p < .05). Inclusion of the DJK-5 peptide into the re-irrigation protocol displayed superior killing rate compared to other protocols (p < .001). CONCLUSIONS: Biofilms exhibited susceptibility to both peptide and non-peptide protocols during re-irrigation, irrespective of nutrient conditions or primary irrigation protocols. The DJK-5 peptide irrigation protocols consistently displayed superior effectiveness compared to non-peptide protocols.