Combination Of EDTA Research Articles

Effects of root canal irrigations on intracanal medication with calcium hydroxide effects in root external resorption models

ObjectiveThe objective of the present in vitro study was to evaluate the influence of endodontic irrigation systems on the removal of smear layer and ion diffusion of calcium hydroxide through dentinal tubules in root external resorption models. Materials and methodsForty single-rooted teeth were divided into four groups (G1, G2, G3, and G4) according to the irrigation regimens: G1, saline solution; G2, 10% sodium hypochlorite with ultrasonic irrigation; G3, 14% EDTA with ultrasonic irrigation; G4, 14% EDTA with ultrasonic irrigation → 10% sodium hypochlorite with ultrasonic irrigation. Ultrasonic irrigation lasted 45 seconds and all the roots were irrigated with 2 mL of saline solution. In experiment 1, the samples were observed on the root canal wall using scanning electron microscope and the percentage of opened dentinal tubules (POD) was calculated. Experiment 2 evaluated the diffusion of calcium ions through dentinal tubules. ResultsIn the middle region of root canals, the mean POD values were 0.11, 5.02, 82.17 and 96.72 in G1, G2, G3, and G4, respectively. In the apical region of root canals, the mean POD values were 0.06, 0.43, 4.41, and 12.70 in G1, G2, G3, and G4, respectively. The diffusion of calcium ions in G4 was significantly high in all groups. ConclusionThis study demonstrated that a combination of EDTA and sodium hypochlorite with ultrasonic irrigation was most effective in removing the smear layer and ion diffusion from the root canal to the surrounding media.

Inhibition and eradication of Salmonella Typhimurium biofilm using P22 bacteriophage, EDTA and nisin

P22 phage >105 PFU ml−1 could be used to inhibit Salmonella Typhimurium biofilm formation by 55–80%. Concentrations of EDTA >1.25 mM and concentrations of nisin >1,200 µg ml−1 were also highly effective in reducing S. Typhimurium biofilm formation (≥96% and ≥95% reductions were observed, respectively). A synergistic effect was observed when EDTA and nisin were combined whereas P22 phage in combination with nisin had no synergistic impact on biofilm formation. Triple combination of P22 phage, EDTA and nisin could be also used to inhibit biofilm formation (≥93.2%) at a low phage titer (102 PFU ml−1), and low EDTA (1.25 mM) and nisin (9.375 µg ml−1) concentrations. A reduction of 70% in the mature biofilm was possible when 107 PFU ml−1 of P22 phage, 20 mM of EDTA and 150 μg ml−1 of nisin were used in combination. This study revealed that it could be possible to reduce biofilm formation by S. Typhimurium by the use of P22 phage, EDTA and nisin, either alone or in combination. Although, removal of the mature biofilm was more difficult, the triple combination could be successfully used for mature biofilm of S. Typhimurium.

Leach of the weathering crust elution-deposited rare earth ore for low environmental pollution with a combination of (NH4)2SO4 and EDTA

High concentration of ammonium sulfate, a typical leaching agent, was often used in the mining process of the weathering crust elution-deposited rare earth ore. After mining, a lot of ammonia nitrogen and labile heavy metal fractions were residual in tailings, which may result in a huge potential risk to the environment. In this study, in order to achieve the maximum extraction of rare earth elements and reduce the labile heavy metal, extraction effect and fraction changes of lanthanum (La) and lead (Pb) in the weathering crust elution-deposited rare earth ore were studied by using a compound agent of (NH4)2SO4-EDTA. The extraction efficiency of La was more than 90% by using 0.2% (NH4)2SO4-0.005 M EDTA, which was almost same with that by using 2.0% (NH4)2SO4 solution. In contrast, the extraction efficiency of Pb was 62.3% when use 0.2% (NH4)2SO4-0.005 M EDTA, which is much higher than that (16.16%) achieved by using 2.0% (NH4)2SO4 solution. The released Pb fractions were mainly acid extractable and reducible fractions, and the content of reducible fraction being leached accounted for 70.45% of the total reducible fraction. Therefore, the use of 0.2% (NH4)2SO4-0.005 M EDTA can not only reduce the amount of (NH4)2SO4, but also decrease the labile heavy metal residues in soil, which provides a new way for efficient La extraction with effective preventing and controlling environmental pollution in the process of mining the weathering crust elution-deposited rare earth ore.

CSE-1034 versus Ceftriaxone: Efficacy and Safety Analysis from a Randomized, Open-labeled Phase III Study in Complicated Urinary Tract Infections.

Objective:The aim of this study was to determine the clinical outcome, microbiological outcome and safety profile of CSE-1034, a novel combination of Ceftriaxone, Sulbactam and EDTA in patients with complicated urinary tract infections (cUTI).Materials and Methods:This was a randomized, controlled, open-labeled Phase-3 trial with the primary objective of assessing the efficacy and safety of CSE-1034 versus Ceftriaxone for the empirical treatment of cUTI. Adult cUTI patients were randomized to receive either intravenous dose of CSE-1034 or Ceftriaxone. The primary end point was composite cure rate (clinical response and bacterial eradication) in mMITT population at test of cure (TOC) visit. Secondary measures included verification of primary endpoint across other visits in different population sets, safety of patients and treatment duration.Results:Overall, 204 patients were enrolled in the study and received one of the two treatments. At primary endpoint (TOC visit), the composite cure rate was much higher in CSE-1034 treatment arm compared to Ceftriaxone arm i.e. 97% (68/70) vs 83% (58/71) (treatment difference 12.6%; 95% CI: 5.9% to 26.4%). The adverse events (AEs) rates reported in two treatment arms were 21% in CSE-1034 and 36% in Ceftriaxone groups. Additionally, the treatment duration in CSE-1034 arm was significantly less (P < 0.05).Conclusions:CSE-1034 3 g every 24 h showed a high favorable clinical and bacteriological response, and 95% CI around the treatment difference prove the superiority of CSE-1034 vs. Ceftriaxone for the treatment of cUTI. Therefore, CSE-1034 provides an effective alternative in the treatment of patients with cUTI.

Effect of retting methods on properties ofDhaincha fibres

The dried ribbons of Sesbania aculeata (Dhaincha) plant were retted by chemical and biological retting methods. In first chemical retting method, the fibres were treated with the combination of EDTA and NaOH whereas in second method pretreated with HCl followed by NaOH; In biological retting method both the stagnant and running water methods were utilized. The retted fibres were tested for physical properties such as, moisture content and weightloss. The percentage weight loss was found to be more in case of chemically retted fibres owing to the enhanced digestibility of lignocellulosic material by the alkali. Contrary to this, biological retting showed higher moisture content due to the presence of non cellulosic matter. Overall, the properties exhibited by Sesbania aculeata fibres obtained after 15 days of stagnant water retting was comparatively good as compared to other retting methods in terms of weight loss and moisture content.

ACCase and rbcL gene expression as a function of nutrient and metal stress for enhancing lipid productivity in Chlorella sorokiniana

Development of novel and scalable strategies for improving lipid and biomass yield is a prerequisite for sustainable biodiesel production from microalgae. Currently, nutrient stress is the widely employed lipid enhancement strategy in microalgae, yet, it is associated with compromised biomass productivity. In this study, an alternative approach for lipid enhancement in Chlorella sorokiniana is proposed to alleviate the constraint of low biomass production under nutrient stress. This is achieved through combining nutrient stress along with selected metals and EDTA stress. A substantial increase in lipid yield (77.03mgL−1d−1) was achieved when the nutrient (nitrogen and phosphorus) stress BG11 media was supplemented with a combination of iron (15mgL−1), magnesium (125mgL−1), calcium (18mgL−1) and EDTA (3mgL−1). This was further validated by quantifying the expression levels of two key genes involved in photosynthesis (rbcL) and lipid biosynthesis (accD) pathways. Under this developed strategy a 5.15-fold increase in rbcL and 9.79-fold increases in accD gene expression were noted in comparison to the culture grown in BG11 medium. A significant correlation could also be drawn between the expression of rbcL and accD genes to biomass yields, photosynthetic performance and lipid productivity. The proposed strategy could be easily applied at various commercial scale microalgal cultivation systems for enhancing lipid content without compromising the biomass yield.

Smear layer removal evaluation of different protocol of Bio Race file and XP- endo Finisher file in corporation with EDTA 17% and NaOCl.

BackgroundThe aim of the present study was to compare the amount of the smear layer remaining in prepared root canals with different protocols of Bio RaCe files and XP-endo Finisher file (XPF) in association with 17% EDTA and sodium hypochlorite solution.Material and MethodsA total of 68 extracted single-rooted teeth were randomly divided into 4 experimental groups (n=14) and two control groups (n=6). The root canals were prepared with Bio RaCe files (FKG Dentaire, Switzerland) using the crown-down technique based on manufacturer’s instructions and irrigated according to the following irrigation techniques: Group 1: XPF with 2 mL of 2.5% NaOCl for 1 minute. Group 2:, XPF with 1 mL of 17% EDTA for one minute. Group 3: XPF was used for 1 minute in association with normal saline solution. Group 4: XP-endo Finisher file for 30 seconds in association with 2.5% NaOCl and 17% EDTA for 30 seconds. The negative control group: NaOCl (2.5%) was used during root canal preparation, followed by irrigation with 17% EDTA at the end of root canal preparation. The positive control group: Normal saline solution was used for irrigation during root canal preparation. In all the groups, during preparation of the root canals with Bio RaCe file, 20 mL of 2.5% NaOCl was used for root canal irrigation and at the end of the procedural steps 20 mL of normal saline solution was used as a final irrigant. The samples were analyzed under SEM at ×1000‒2000 magnification and evaluated using Torabinejad scoring system. Data were analyzed with non-parametric Kruskal-Wallis test and post hoc Mann-Whitney U test, using SPSS. Statistical significant was defined at P<0.05.ResultsThe results of the study showed the least amount of the smear layer at coronal, middle and apical thirds of the root canals in groups 2, which was not significantly different from the negative control group (P<0.5).ConclusionsUnder the limitations of the present study, use of a combination of NaOCl and EDTA in association with XPF exhibited the best efficacy for the removal of the smear layer. Key words:Smear layer, XP-endo Finisher file, EDTA, Sodium hypochlorite.

Ultrastructural analysis of uninstrumented root canal areas following various irrigation regimens

Abstract Introduction During endodontic treatment smaller or larger areas of root canal wall remain non-instrumented. This can affect prognosis of endodontic treatment as some bacteria may be left behind. The purpose of this study was to evaluate the morphology of non-instrumented areas of the root canal wall using scanning-electron-microscopy (SEM) after completed instrumentation and various irrigation regiments. Materials and Methods Eighteen single-rooted extracted teeth were divided into the six groups. One tooth in each group represented a control sample. In all samples only one half of the canal was instrumented using ISO 40 hand files. Control samples were subjected to an irrigation protocols without instrumentation. Irrigants used were physiological saline, 3% sodium hypochlorite and 15% of ethylene-diamine-tetra-acetate. Irrigation protocol included using each of these irrigants alone, or a combination of NaOCl and EDTA, as well as their combination with final irrigation using NaOCl or chlorhexidine. Then after, roots were sectioned longitudinally and prepared for SEM. Results Saline irrigation left pulpal debris on uninstrumented areas of the canal wall. Irrigation with 3% NaOCl left behind canal wall with different forms of calcospherites. However, after EDTA irrigation dentin appeared as an undulating surface with open tubules without a smear layer. The combination of NaOCl and EDTA showed remnants of calcospherites and open slightly widened dentinal tubules. Final irrigation with NaOCl on the uninstrumented areas showed enlarged dentinal tubules along with dentinal erosion, while after final irrigation with CHX clean dentin and open dentinal tubules without smear layer were noted. Conclusion From the morphological point of view, the most favorable effect of irrigation on both uninstrumented and uninstrumented canal walls was achieved after irrigation with NaOCl and EDTA or NaOCl, EDTA and chlorhexidine as the final irrigant.

Effect of different activated coatings containing enterocin AS-48 against Listeria monocytogenes on apple cubes

Abstract Enterocin AS-48 is a circular bacteriocin with strong anti- Listeria activity. The purpose of the present study was to evaluate the effect of the bacteriocin incorporated into different coating solutions on a cocktail of five L. monocytogenes strains previously inoculated on apple cubes. Coating solutions were made with chitosan, caseinate, alginate, k-carrageenate, xanthan gum, pectin, starch, carboxymethyl cellulose or methyl cellulose. Coatings were applied singly or combined with enterocin AS-48 at 20 or 40 μg/ml. Samples were stored at 4 °C for 7 days. The single application of coatings had almost no effect (as in alginate and methyl cellulose) or had a low effect on Listeria viability ( Listeria activity (up to 3.7 log cycles at day 7). Coatings dosed with 20-μg/ml enterocin AS-48 reduced viable Listeria counts gradually during storage in most cases, achieving significant reductions (p Listeria counts below detection levels from day 1 for most of the coatings tested. The combination of EDTA and AS-48 was also the most effective at time 0, achieving reductions of viable counts between 2.0 and 2.7 log cycles depending on the coating immediately after treatment compared with single coatings. Industrial relevance Results from the present study suggest the potential of edible coatings containing enterocin AS-48 and EDTA for inactivation of L. monocytogenes on apple surfaces. Since edible coatings are widely used on fruit surfaces, coatings activated with enterocin AS-48 and EDTA could find application as a hurdle against L. monocytogenes in fresh-cut apple pieces.

Component Analysis of Multipurpose Contact Lens Solutions To Enhance Activity against Pseudomonas aeruginosa and Staphylococcus aureus.

More than 125 million people wear contact lenses worldwide, and contact lens use is the single greatest risk factor for developing microbial keratitis. We tested the antibacterial activity of multipurpose contact lens solutions and their individual component preservatives against the two most common pathogens causing bacterial keratitis, Pseudomonas aeruginosa and Staphylococcus aureus The in vitro antibacterial activity of five multipurpose contact lens solutions (Opti-Free GP, Boston Simplus, Boston Advance, Menicare GP, and Lobob) was assayed by the standard broth dilution method. Synergy between the preservative components found in the top performing solutions was assayed using checkerboard and time-kill assays. The ISO 14729 criteria and the standard broth dilution method were used to define an optimized contact lens solution formulation against a clinical panel of drug-susceptible and drug-resistant P. aeruginosa and S. aureus strains. Preservatives with the biguanide function group, chlorhexidine and polyaminopropylbiguanide (PAPB), had the best antistaphylococcal activity, while EDTA was the best antipseudomonal preservative. The combination of chlorhexidine and EDTA had excellent synergy against P. aeruginosa A solution formulation containing chlorhexidine (30 ppm), PAPB (5 ppm), and EDTA (5,000 ppm) had three to seven times more antipseudomonal activity than anything available to consumers today. A multipurpose contact lens solution containing a combination of chlorhexidine, PAPB, and EDTA could help to reduce the incidence of microbial keratitis for contact lens users worldwide.

Role of reducing agent in extraction of arsenic and heavy metals from soils by use of EDTA

Although many metal-contaminated sites contain both anionic arsenic and cationic heavy metals, the current remediation technologies are not effective for the simultaneous removal of both anionic and cationic elements from the contaminated sites due to their different characteristics. In this study, the role of reducing agent in simultaneous extraction of As, Cu, Pb, and Zn from contaminated soils was investigated using EDTA. The addition of reducing agents, which includes sodium oxalate (Na2C2O4), ascorbic acid (C6H8O6) and sodium dithionite (Na2S2O4), greatly enhanced the EDTA extraction of both As and heavy metals from the contaminated soils due to the increased mobility of the metals under the reduced conditions. The extent of the enhancement of the EDTA extraction was greatly affected by the reducing conditions. Strong reducing conditions (0.1 M of dithionite) were required for the extraction of metals strongly bound to the soil, while weak reducing conditions (0.01 M of dithionite or 0.1 M of oxalate/ascorbic acid) were sufficient for extraction of metals that were relatively weakly bound to the soil. An almost 90% extraction efficiency of total metals (As, Cu, Zn, and Pb) was obtained from the contaminated soils using the combination of dithionite and EDTA. Our results clearly showed that the combination of dithionite and EDTA can effectively extract As and heavy metals simultaneously from soils under a wide range of pH conditions.

EFFECT OF DIFFERENT IRRIGATING SOLUTIONS AND MECHANICAL AIDS ON THE REMOVAL OF CALCIUM HYDROXIDE INTRA-CANAL MEDICATION FROM STRAIGHT AND CURVED CANALS

aim: to study effect of different irrigating solutions and mechanical aids on Ca(OH)2 removal from straight and curved canals. materials and methods: Forty five maxillary central incisors with straight roots (group I) were prepared with step back technique until apical size 55 and forty five mandibular first molars with curved mesio buccal canals (group II) prepared with Pro Taper universal system up to apical size F2. Calcium hydroxide was applied into all canals and the accesses were sealed with temporary dressing. All teeth were placed in wax mould and digital radiographs were taken to confirm canal filling with Ca(OH)2 to length. Every group was subdivided into 3 subgroups according to the irrigating solution used; subgroup A irrigated with 5.25% NaOCl only, subgroup B irrigated with 5.25% NaOCl and 10% H2O2, and subgroup C irrigated with 5.25% NaOCl and 17% EDTA. Every subgroup was further subdivided into 3 subgroups (1, 2, and 3) according to the mechanical aid for Ca(OH)2 removal; in subgroup 1 used master apical file, in subgroup 2 used master apical file and apical patency, in subgroup 3 used master apical file, apical patency and increase in canal size. Post removal digital radiographs were taken for all teeth in their wax mould. Any traces of Ca(OH)2 were traced by “Image J” software and estimated as a percentage to the total canal space and statistically analyzed. results: There was no significant difference between the subgroups A, B, and C in anterior and posterior teeth either in subgroup 1, 2, or 3. In anterior teeth group, there were significant differences between subgroups 1, 2, and 3 in subgroup B and C but, in subgroup A, there was no significant difference. In posterior teeth group, there was a significant difference between subgroups 1, 2, and 3. in subgroup A but, in subgroup B and C, there was no significant difference. Anterior and posterior teeth were compared and the results were significant differences in subgroups A1 and A2 but, in subgroup A3 there was no significant difference. In subgroup B, there were significant differences in subgroups B1, B2 and B3. In subgroup C, there was no significant difference in subgroups C1, C2 and C3. conclusions: Under the tested conditions of this study, the most successful method of Ca(OH)2 removal was the use of master apical file (hand or rotary), apical patency and increase one size filing with the combination of EDTA and NaOCl irrigation in both anterior & posterior teeth.

Temperature and pH influence the susceptibility of Salmonella Typhimurium to nisin combined with EDTA

Lantibiotics, such as nisin, generally act on Gram-positive bacteria, whereas Gram-negative bacteria exhibit natural resistance to the action of these bacteriocins. However, Gram-negative bacteria can become susceptible to the action of these antimicrobial peptides with the use of chelating agents, such as EDTA. The activity of bacteriocins can be influenced by several factors, such as environmental conditions and chemical composition of the medium. Moreover, the susceptibility of target microorganism can be altered, due to changes in cellular composition induced by environmental conditions. In this study, we examined the combined effect of variations in temperature and pH on the susceptibility of Salmonella Typhimurium to the action of nisin associated with EDTA. The reduction in the number of viable cells of Salmonella Typhimurium varied according to the temperature and pH, and major reduction in logarithmic cycles of viable cells occurred with a temperature increase. Under low temperature and low pH, a considerable reduction in the viability was also observed after prolonged exposure to bacteriocin, regardless of the presence of EDTA. According to results, temperature and pH conditions influence on the susceptibility of Salmonella Typhimurium to combination of nisin and EDTA and thus should be considered to establish optimal conditions for nisin use.

Blood clot stabilization on root dentin conditioned by the combination of tetracycline and EDTA

Blood clot stabilization on root dentin conditioned by the combination of tetracycline and EDTA

Ionic strength, antioxidants and chelators affect whey protein isolates' antioxidantion in water‐in‐walnut oil emulsions

The objective of this research was to evaluate the impact of factors, such as ionic strength, free radical scavengers, and chelators, on lipid oxidation in water‐in‐walnut oil (W/O) emulsions containing whey protein isolates (WPI). The incorporation of WPI in aqueous phase could retard lipid oxidation in W/O emulsions, indicating WPI were antioxidants in the emulsions. Low levels of ionic strength (≤50 mM NaCl) in aqueous phase improved the oxidative stability of W/O emulsions containing WPI, whereas high levels of ionic strength (≥100 mM NaCl) accelerated lipid oxidation in the emulsions. Free radical scavengers (e.g. Trolox and α‐tocopherol) could increase the oxidative stability of W/O emulsions with the incorporation of Trolox in the emulsion inhibiting lipid oxidation more strongly than α‐tocopherol. This indicated that polar antioxidants were more effective at retarding lipid oxidation than non‐polar antioxidants. The addition of WPI and free radical scavengers combined made the emulsions oxidize more slowly than either substance used alone, suggesting there were synergistic effects between them. The use of both EDTA and citric acid could inhibit lipid oxidation in W/O emulsions, indicating that endogenous transition metals were the major prooxidants in W/O emulsions. The combination of WPI and EDTA or CA could further lower the rates of lipid oxidation in W/O emulsions.Practical applications: Whey protein isolates inhibit lipid oxidation in oil‐in‐water (O/W) emulsions. From the present study, it became clear that WPI could also retard lipid oxidation in water‐in‐oil (W/O) emulsions. However, the antioxidant activity of WPI was affected by factors such as ionic strength, free radical scavengers, and chelators. This research pointed out that the incorporation of whey proteins in W/O emulsions, such as spreads, chocolate, and butter, could increase the oxidative stability of the emulsions. Moreover, the appropriate choice of ionic strength, free radical scavengers, and chelators could promote the antioxidation of WPI in W/O emulsions.Schematic demonstration of the impact of ionic strength on lipid oxidation in water‐in‐walnut oil emulsions containing 0.2 wt% WPI during storage at 45°C in the dark for up to 20 days. Low levels of ionic strength (≤ 50 mM NaCl) improved the oxidative stability of W/O emulsions containing WPI, whereas high ionic strength (≥100 mM NaCl) accelerated lipid oxidation in the emulsions.

Abiotic reductive extraction of arsenic from contaminated soils enhanced by complexation: Arsenic extraction by reducing agents and combination of reducing and chelating agents

Abiotic reductive extraction of arsenic from contaminated soils was studied with various reducing agents and combinations of reducing and chelating agents in order to remediate arsenic-contaminated soils. Oxalate and ascorbic acid were effective to extract arsenic from soil in which arsenic was associated with amorphous iron oxides, but they were not effective to extract arsenic from soils in which arsenic was bound to crystalline oxides or those in which arsenic was mainly present as a scorodite phase. An X-ray photoelectron spectroscopy study showed that iron oxides present in soils were transformed to Fe(II,III) or Fe(II) oxide forms such as magnetite (Fe3O4, FeIIFe2IIIO4) by reduction with dithionite. Thus, arsenic extraction by dithionite was not effective due to the re-adsorption of arsenic to the newly formed iron oxide phase. Combination of chelating agents with reducing agents greatly improved arsenic extraction from soil samples. About 90% of the total arsenic could be extracted from all soil samples by using a combination of dithionite and EDTA. Chelating agents form strong complexation with iron, which can prevent precipitation of a new iron oxide phase and also enhance iron oxide dissolution via a non-reductive dissolution pathway.

Metal leaching from cathode ray tube waste using combination of Serratia plymuthica and EDTA

Bioassisted processes have been continuously expanding its applications for the discovery of new eco friendly, economic and efficient technique for the metal extraction from e-waste scrap, as a valuable mineral resource. Proposed hybrid combination is expanding the application of metal bioleaching from waste CRT by using Serratia plymuthica and EDTA. To the best of our knowledge, this is the first report to use microbe (S. plymuthica) and chemical (EDTA) combination for the improvement of metal leaching from waste CRT. Microbe for this study is isolated through the soil collected from CRT collection/recycling site at Dehradun (India). The selected combination is capable to enhance the leaching rate as compared to the leaching with individual microbe or chemical. Mechanistically it can be explained by: (i) enhancement in metal mobility by the formation of metal hydrous oxide and; (ii) mononuclear to multinuclear complex shifting. A second order mechanism for leaching is also proposed to predict the rate constant for the leaching.

Effect of Different Final Irrigation Methods on the Removal of Calcium Hydroxide from an Artificial Standardized Groove in the Apical Third of Root Canals

IntroductionThe aim of this study was to compare the efficacy of conventional syringe, ultrasonic, EndoVac (Discus Dental, Culver City, CA), and Self-Adjusting File (SAF) (Re-Dent-Nova, Ra'nana, Israel) irrigation systems in removing calcium hydroxide (Ca[OH]2) from simulated root canal irregularities. MethodsThe root canals of 88 extracted single-rooted teeth were prepared using ProTaper rotary instruments (Dentsply Maillefer, Ballagiues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and Ca(OH)2 medicament was placed into the root canals using a Lentulo spiral. The roots were randomly divided into 4 experimental groups and 2 control groups according to the different irrigation systems used: conventional syringe irrigation, continuous passive ultrasonic irrigation (PUI), EndoVac irrigation, and SAF irrigation. Each group was then divided into 2 subgroups (n = 10) according to the irrigation protocol: subgroup 1: 10 mL 2.5% NaOCl and subgroup 2: 10 mL 17% EDTA + 10 mL 2.5% NaOCl. The amount of remaining medicament was evaluated under a stereomicroscope at 30× magnification using a 4-grade scoring system. The influences of the different Ca(OH)2 medicament removal methods and irrigation protocols were statistically evaluated using 2-way analysis of variance and Tukey post hoc tests. ResultsIn the NaOCl-irrigated groups, PUI removed significantly more Ca(OH)2 medicament than the other techniques (P < .05). There was no significant difference among the other groups (P > .05). In the EDTA/NaOCl-irrigated groups, the SAF and PUI removed significantly more Ca(OH)2 than the other techniques (P < .05). ConclusionsThe use of the SAF system with the combination of EDTA and NaOCl enhanced Ca(OH)2 removal when compared with the use of only NaOCl irrigation with the SAF. Continuous PUI and SAF were more effective than EndoVac, and conventional syringe irrigation in the removal of the Ca(OH)2 medicament from an artificial standardized groove in the apical part of the root canal.

English

Many clinically relevant species of Gram-negative bacilli are often resistant to β-lactam antibiotics even to carbapenems. According to CLSI guideline 2013, Carbapenemase producers are screened by zone size <21mm to Meropenem or Etrapenem and phenotypically confirmed by Modified Hodge test. The test of Hodge et al was modified by substituting Escherichia coli for penicillin-susceptible Staphylococcus aureus ATCC 25923, and 10-µg Imipenem disk for a 10-U Penicillin disk. While looking for the Carbapenemase producing strains, some astonishing, unexplainable facts were revealed in this study. Meropenem-resistant test strains were screened (zone diameter in Modified Kirby-Bauer technique<21mm) & for phenotypic confirmation of Carbapenemase production, modified Hodge test was performed. Thereafter the test strains were examined for production of Metallo β Lactamase using Imipenem (10µg) disk and combination of Imipenem and EDTA, followed by test for Bacteriocin production. Two Acinetobacter and one Pseudomonas aeruginosa strains were found to produce a Star like outward distortion. They did not produce Metallo β lactamase. Moreover, screening test for bacteriocin production was also found to be negative. The strains resistant to Carbapenem antibiotics but nonproducers of metallo β lactamase and/or Bacteriocins, have left behind a head twister for us.

A Comparative Scanning Electron Microscopy Evaluation of Smear Layer Removal from Teeth with Different Irrigation Solutions and Lasers

The aim of this study was to evaluate the efficacy of smear layer removal from teeth following root canals using lasers (Er:YAG and Nd:YAG), NaOCl, 17% EDTA, and MTAD by scanning electron microscopy (SEM). Root canals were irrigated with 3 mL of 5.25% NaOCl after each file. Teeth were randomly divided into five groups. In the final irrigation, canals were irrigated with 5.25% NaOCl (Group 1, control), 17% EDTA (Group 2), or BioPure MTAD (Group 3). Laser groups were irradiated with Er:YAG laser (1.8 W, 120 mJ, 15 Hz) (Group 4) or Nd:YAG laser (1 W, 100 mJ, 15 Hz) (Group 5). The smear layer at the apical, middle, and coronal thirds of each root canal was imaged using SEM. Smear layer removal by EDTA was the most effective in all regions. The difference between EDTA and MTAD was statistically significant in the coronal and middle (p < 0.05), but not the apical (p > 0.05), regions. The difference between the control and laser groups was not statistically significant (p > 0.05). In all regions, the difference between 17% EDTA-MTAD and the control-laser groups was statistically significant (p < 0.05). Although improvement was observed in removal of the smear layer using alternative materials and techniques, application of a combination of EDTA and NaOCl remains an effective technique.