The antibacterial activity of sodium hypochlorite and chlorhexidine against Enterococcus faecalis: A review on agar diffusion and direct contact methods

Injectable Methacrylated Gelatin Hydrogel for Safe Sodium Hypochlorite Delivery in Endodontics

Keeping sodium hypochlorite (NaOCl) within the root canal is challenging in regenerative endodontics. In this study, we developed a drug delivery system using a gelatin methacryloyl (GelMA) hydrogel incorporated with aluminosilicate clay nanotubes (HNTs) loaded with NaOCl. Pure GelMA, pure HNTs, and NaOCl-loaded HNTs carrying varying concentrations were assessed for chemo-mechanical properties, degradability, swelling capacity, cytocompatibility, antimicrobial and antibiofilm activities, and in vivo for inflammatory response and degradation. SEM images revealed consistent pore sizes of 70-80 µm for all samples, irrespective of the HNT and NaOCl concentration, while HNT-loaded hydrogels exhibited rougher surfaces. The hydrogel's compressive modulus remained between 100 and 200 kPa, with no significant variations. All hydrogels demonstrated a 6-7-fold mass increase and complete degradation by the seventh day. Despite an initial decrease in cell viability, all groups recovered to 65-80% compared to the control. Regarding antibacterial and antibiofilm properties, 12.5 HNT(Double) showed the highest inhibition zone on agar plates and the most significant reduction in biofilm compared to other groups. In vivo, the 12.5 HNT(Double) group displayed partial degradation after 21 days, with mild localized inflammatory responses but no tissue necrosis. In conclusion, the HNT-NaOCl-loaded GelMA hydrogel retains the disinfectant properties, providing a safer option for endodontic procedures without harmful potential.

Antimicrobial overproduction sustains intestinal inflammation by inhibiting Enterococcus colonization

Loss of antimicrobial proteins such as REG3 family members compromises the integrity of the intestinal barrier. Here, we demonstrate that overproduction of REG3 proteins can also be detrimental by reducing a protective species in the microbiota. Patients with inflammatory bowel disease (IBD) experiencing flares displayed heightened levels of secreted REG3 proteins that mediated depletion of Enterococcus faecium (Efm) from the gut microbiota. Efm inoculation of mice ameliorated intestinal inflammation through activation of the innate immune receptor NOD2, which was associated with the bacterial DL-endopeptidase SagA that generates NOD2-stimulating muropeptides. NOD2 activation in myeloid cells induced interleukin-1β (IL-1β) secretion to increase the proportion of IL-22-producing CD4+ T helper cells and innate lymphoid cells that promote tissue repair. Finally, Efm was unable to protect mice carrying a NOD2 gene variant commonly found in IBD patients. Our findings demonstrate that inflammation self-perpetuates by causing aberrant antimicrobial activity that disrupts symbiotic relationships with gut microbes.

Antimicrobial efficacy of chlorine agents against selected oral pathogens

OBJECTIVES

Method-dependent comparison of antimicrobial agents' efficacy against oral pathogens.

MATERIALS AND METHODS

Several sodium hypochlorite solutions (NaOCl)-Perisolv®, Carisolv® and Dakin's solution-were equated with chlorhexidine (CHX) and hydrogen peroxide (H2O2) against ten oral micro-organisms related to caries and periodontitis using different minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) techniques. Agents were adjusted to the final 70 mmol/L concentration of active chlorine molecule.

RESULTS

Apart from H2O2 and the amino acids of Perisolv®, all the agents revealed an antimicrobial effect. Agar diffusion test ranked CHX (p < 0.05) as the most effective against all ten specimens, followed by the NaOCl of Perisolv® and Dakin's solution. Correspondingly, in broth microdilution on agar, CHX was the most effective in eradicating micro-organisms at 0.03 mmol/L compared with 2.2 mmol/L of Dakin's solution. In contrast, the bactericidal concentration of Dakin's solution was the most effective at 0.2 mmol/L, (p < 0.001), followed by Perisolv® (2.14 mmol/L), CHX (2.38 mmol/L) and Carisolv® (3.33 mmol/L) after 5 and 10 min in broth dilution test. In live/dead analysis, 60-min exposure to a 2-fold concentration of agents resulted in two-log Aggregatibacter actinomycetemcomitans inhibition by CHX (35 mmol/L) whilst Streptococcus mutans was more susceptible, in 0.8 and 8.8 mmol/L, after 10 min to CHX and Dakin's respectively.

CONCLUSION

Replacement of CHX with tested hypochlorite agents showed evident potential and promoted rapid antimicrobial effect.

CLINICAL RELEVANCE

Effective antimicrobial agents are crucial in controlling pathogen-induced oral infections increasing clinical possibilities to combat oral biofilms. Additionally, CHX substitution with hypochlorite agents could eliminate CHX's adverse effects.

The clinical effect of sodium hypochlorite oral rinse on peri-implantitis lesion: A pilot study

Peri-implantitis poses an imminent challenge to the field of implant dentistry. Considering the promising findings of sodium hypochlorite and periodontal lesions, the aim of the present study was to evaluate the clinical effects of sodium hypochlorite oral rinse on peri-implantitis lesions. Twelve peri-implantitis patients were instructed to rinse with 15 mL of a fresh solution of 0.25% sodium hypochlorite for 30 s twice a week for 3 months. At baseline and 3-month visits, probing depth and modified sulcular bleeding index were recorded at 6 points per lesion (mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual). Individual and total bacterial loads of 18 pre-designated species of microorganisms were analyzed by real-time PCR methods. Probing depth decreased after the experiment, with an average difference of 1.1 mm and a standard deviation of 1.7 mm. The modified sulcular bleeding index decreased by a mean value of 0.8 with a standard deviation of 1.1. This study demonstrated the clinical effects of sodium hypochlorite oral rinse on peri-implantitis lesions and the reduction of periodontal probing depth and gingival bleeding index. This study suggested that the concentration of 0.25% be used for treatment of peri-implantitis.

Antibacterial Effect of Matricaria chamomilla L. Extract Against Enterococcus faecalis

Purpose

With the demand for better efficiency during endodontic therapy, the purpose of this in vitro study was to evaluate the efficiency of ethyl acetate (EthOAc) extract of Matricaria chamomilla (L.) against Enterococcus faecalis and compare with standard root canal irrigation solutions.

Material and Methods

The antibacterial effect against Enterococcus faecalis of the EthOAc extract of Matricaria chamomilla was assessed without, or with dentine powder, using agar disk diffusion method. The inhibition zones induced by the EthOAc extract were observed after 5 minutes, 60 minutes, and 24 hours and compared with standard irrigation solutions (2% chlorhexidine and 2% sodium hypochlorite) without, or after mixing with dentine powder. Statistical analysis of the results were analysed with the Kruskal-Wallis test and one-way ANOVA.

Results

There was no inhibition zone in samples with and without dentine powder after combination of ethyl acetate extract of Matricaria chamomilla with sodium hypochlorite. When the extract was used alone in samples without dentine powder, the inhibition zone was 9.7 mm after 24 h, but this zone was decreased after adding dentine powder (7.7 mm). When the extract was used in combination with CHX, the inhibition zone in samples with dentine powder was 25.3 mm, but it was decreased after adding dentine powder (21.7 mm).

Conclusion

The EthOAc extract of Matricaria chamomilla as alternative root canal irrigant may be a useful natural agent with antibacterial activity against Enterococcus faecalis. Also, it showed promising results in endodontic therapy after combination with chlorhexidine in Enterococcus faecalis eradication.

A Comparative Evaluation of Antibacterial Efficacy of Moringa oleifera Leaf Extract, Octenidine Dihydrochloride, and Sodium Hypochlorite as Intracanal Irrigants against Enterococcus faecalis: An In Vitro Study

Objectives

The aim of this study is to investigate and compare the microbial efficacy of Moringa oleifera leaf extract, octenidine dihydrochloride (OCT), NaOCl, and their combinations as intracanal irrigants against Enterococcus faecalis.

Materials and Methods

Sixty single-rooted mandibular premolars were decoronated followed by root canal preparation. Each root specimen was autoclaved, inoculated with E. faecalis, and incubated at 37°C for 48 hr. Then, the specimens were divided into six groups based on the irrigation solution used: 2.5% NaOCl (Group 1), 0.1% OCT (Group 2), M. oleifera leaves extract (Group 3), a combination of M. oleifera extract and 1.25% NaOCl (Group 4), a combination of M. oleifera extract and OCT (Group 5) and normal saline (Group 6). Microbial samples were taken from each root canal before (S1) and after (S2) irrigation and the bacterial viability was assessed using colony-forming units (CFU) on bile esculin agar plates.

Results

Comparing the number of CFU/ml before and after irrigation showed a significant reduction (P < 0.001) in all studied groups. Comparison between the CFU/ml after irrigation by NaOCl and each of the combination groups showed a significant difference.

Conclusion

M. oleifera leaves extract and 0.1% OCT solutions have antibacterial effect against E. faecalis comparable to 2.5% NaOCl and might be used as root canal irrigants. The combination groups showed better antimicrobial activities than individual irrigants. However, further studies are required to investigate the biocompatibility and possible toxic effects of the tested irrigants.

Antibacterial Activity of Gallic Acid from the Leaves of Altingia excelsa Noronha to Enterococcus faecalis

AIM : The aim of this study was to determine the antibacterial compound of Altingia excelsa leaves to inhibit the growth of Entrococcus faecalis. METHODS : The study was true experimental laboratory design. Separating the ethyl acetate extract via their compounds using various chromatographic techniques. Four extracts from A. excelsa leaves was obtained by the maceration method. The highest inhibitory effect was then continued to be isolated until one compound was obtained. Therefore, additional assay to determine chemical structure of compounds was done using UV spectra, infrared (IR), core magnetic resonance (NMR), and comparison with spectra data from the literature. The data were analyzed by ANACOVA assay. RESULTS : The highest inhibitory effect was the ethyl acetate extract. The chemical structure of compound 1 was identified as an acidic compound 3,4,5 -trihydroxy benzoate, namely as the gallic acid which had inhibitory effect against Enterococcus faecalis. Antibacterial test against Enterococcus faecalis was done to determine inhibitory effect by its compound and MIC values showed of 12.25 µg/mL. CONCLUSION : Gallic acid as the compound of Altingia excelsa leaves had a strong inhibitory effect to Enterococcus faecalis.

Pharmacokinetic control on the release of antimicrobial drugs from pH-responsive electrospun wound dressings

The acidic pH of healthy skin changes during wound healing due to the exposure of the inner dermal and subcutaneous tissue and due to the potential colonization of pathogenic bacteria. In chronic non-healing wounds, the pH values vary in a wide pH range but the appearance of an alkaline shift is common. After a wound is incurred, neutral pH in the wound bed is characteristic of the activation of the cascade of regenerative and remodeling processes. In order to adjust drug release to the specific pH of the wound, herein, drug-loaded wound dressings having pH-responsiveness containing antiseptics and antibiotics and exerting different release kinetics in order to have a perfect match between the drug release kinetics, and the pH conditions of each wound type, were developed. We have fabricated drug-loaded electrospun nanofibers loaded with the antiseptic chlorhexidine, with the broad-spectrum antibiotic rifampicin, and with the antimicrobial of natural origin thymol, using the pH-dependent methacrylic acid copolymer Eudragit® L100-55, which dissolves at pH > 5.5; those drugs were loaded within Eudragit® S100, which dissolves at pH > 7 and, finally, within the methacrylic ester copolymer Eudragit® RS100 which is pH independent and slowly erodes and releases its contained cargo. The antibacterial action of those advanced wound dressings has been evaluated against methicillin-sensitive S. aureus Newman strain expressing the coral green fluorescent protein (cGFP), as a model of a Gram-positive bacteria, and against E. coli S17 strain as a model of a Gram-negative bacteria. It was demonstrated that those combinational products integrate in one device the required characteristics for a wound dressing with the therapeutic action of a contained active principle and can be selected depending on the wound acidic or alkaline status for its appropriated management.

A Comparative Evaluation of Antimicrobial Efficacy of Novel Surfactant-Based Endodontic Irrigant Regimen's on Enterococcus faecalis

Introduction

Irrigants play an important role in the eradication of microorganisms in the complex root canal system. Sodium hypochlorite (NaOCl), chlorhexidine (CHX), and iodine potassium iodide (IKI) have certain limitations despite their routine clinical use. Surfactant irrigants with antimicrobial properties can be a milestone in endodontics to overcome the drawbacks of conventional irrigants. The aim of this study was to evaluate the antimicrobial efficacy of surfactants in comparison with routine endodontic irrigants on Enterococcus faecalis.

Materials and Methods

Primary irrigants NaOCl, CHX, IKI were prepared at concentrations of 5%, 2.5%, 2%, and 1%; while mixture of tetracycline acid and detergent (MTAD) (100%) served as control group. Surfactants such as cetrimide (CTR) and sodium dodecyl sulfate (SDS) were prepared at concentrations of 0.5%, 1%, and 2%. The direct contact assay was used to evaluate the antimicrobial efficacy after 5 min. Statistical analysis was performed using one-way ANOVA and Mann-Whitney U-test.

Results

In the primary group, only 5% CHX was significant over MTAD (P < 0.05). In the surfactant group, all concentrations of CTR and SDS (except 0.5%) were significant (P < 0.05) in killing E. faecalis over MTAD. Two percent CHX in combination with 0.5% CTR and 1% SDS had an effective kill percentage over 2% CHX and MTAD alone.

Conclusion

Surfactant irrigant regimens can be used as adjuncts with CHX to overcome its clinical limitations and potentiate its substantivity, thereby enhancing clinical success in endodontics.

Perumal L, Prabha E. An In Vitro comparison of the effect of wound irrigating solution (0.01% hypochlorous acid) and 2.5% sodium hypochlorite against enterococcus faecalis

Aim:

The aim of this in vitro study was to evaluate and compare the antimicrobial activity of normal saline, 2.5% sodium hypochlorite, and 0.01% hypochlorous acid against Enterococcus faecalis.

Materials and Methods:

Antimicrobial activity was assayed by Kirby–Bauer cup-well agar diffusion method. Three cup-wells were bored in each petriplate and were filled with 50 μl of each of the respective test agents. Culture plates were placed in an incubator at 37°C and after 24 hours, the size of the magnification inhibition zone was quantified with a caliper and recorded in respective tables. The experiment was reiterated ten times for each reagent, and the diameter of the magnification inhibition zones caused by the irrigation solutions was recorded. The antimicrobial activity of the three test solutions was determined.

Results:

The antibacterial property of the three groups was compared by utilizing ANOVA test. The association was found to be statistically significant (P = 0.000). The antibacterial property between 2.5% NaOCl and 0.01% HOCl was further compared with independent t test. This association was however not statistically significant (P = 0.02).

ANTIMICROBIAL AGENTS AND ANTI-ADHESION MATERIALS FOR MEDICAL AND SURGICAL GLOVES

Healthcare-associated infections (HAIs) can be common in healthcare settings, such as the intensive care unit and surgical sites, if proper precautions are not followed. Although traditional techniques are encouraged, such as educating the public and healthcare workers to practice proper handwashing or to double glove, they have not been fully effective in combating HAIs. The use of surface-modified antimicrobial gloves may be an alternative approach to prevent the transmission of pathogens between healthcare workers and patients. This paper gives a comprehensive review of strategies to produce antimicrobial gloves. The chemistry of some potential chemically synthesized antimicrobial agents and nature-inspired superhydrophobic surfaces are discussed. The principles of killing microbes must be understood to effectively select these materials and to design and fabricate surfaces for the reduction of bacterial adhesion. Also, current company trends and technologies are presented for gloves proven to effectively kill bacteria. Such glove use, when coupled with in-depth research on diverse surgical procedures and medical examinations, could ease the burden of HAIs.

In vitro inhibitory effects of commercial antiseptics and disinfectants on foodborne and environmental bacterial strains

Background: Antibacterial agents, including disinfectants and antiseptics are commonly used to reduce bacterial loads. As they have a broad-spectrum of activity against bacteria, function either as bactericidal or bacteriostatic agents. While bacterial antimicrobial resistance is increasing, disinfectants and antiseptics are still relevant antibacterial agents.   Methods:  This study investigated the in vitro inhibitory effects of commonly used antiseptics and disinfectants. Using standard disc diffusion methods, selected common household antibacterial agents were tested on resistant Staphylococcus aureus isolated from hospital environment and foodborne Escherichia coli and Bacillus species. Results: The study showed that the selected antibacterial agents were effective against the antibiotic resistant bacteria with appreciable zone of inhibition relative to the standard controls used. Conclusions: Though bacteria are consistently developing resistance to available antibiotics, disinfectants still inhibit bacterial growth and survival with considerable public health importance.

Accidental Injection of Chlorhexidine during Endodontic Therapy

The use of chlorhexidine gluconate (CHX) as an irrigating solution in an anesthesia cartridge is a wrong procedure commonly performed in daily clinical practice. Being an invasive procedure, it is invariably associated with complications. A 47-year-old healthy woman was injected accidentally with 2% CHX in the buccal vestibular area instead of an anesthetic solution during a root canal treatment. After the injection, the patient experienced local side effects, such as a burning sensation on the right cheek area, also a discomfort perception at the injection site and a slight inflammation with a mild extraoral redness especially on the right side cheek. The patient was prescribed with antibiotics and anti-inflammatories to reduce pain and inflammation. The patient complained of upper lip numbness by the second day of the accident. The extraoral swelling reduced gradually and the redness diminished considerably over a period of 6 days. At day 60 of follow-up, the patient recovered satisfactorily from extraoral inflammation but still presented a slight numbness of the upper lip. As a conclusion, we can claim that anesthesia cartridges with irrigant solutions should never be used to irrigate the root canals, and accidental injection of CHX should be carefully assessed by the clinician.

In vitro inhibitory effects of commercial antiseptics and disinfectants on foodborne and environmental bacterial strains

Background: Antibacterial agents, including disinfectants and antiseptics are commonly used to reduce bacterial loads. As they have a broad-spectrum of activity against bacteria, function either as a bactericidal or bacteriostatic. While bacterial antimicrobial resistance is increasing, disinfectants and antiseptics are still relevant antibacterial agents.   Methods:  This study investigated the in vitro inhibitory effects of commonly used antiseptics and disinfectants. Using standard disc diffusion methods, selected common household antibacterial agents were tested on resistant Staphylococcus aureus isolated from hospital environment and foodborne Escherichia coli and Bacillus species. Results: The study showed that the selected antibacterial agents were effective against the antibiotic resistant bacteria with appreciable zone of inhibition relative to the standard controls used. Conclusions: Though bacteria are consistently developing resistance to available antibiotics, disinfectants still inhibit bacterial growth and survival with considerable public health importance.

Properties of a modified quaternary ammonium silane formulation as a potential root canal irrigant in endodontics

OBJECTIVES

Evaluate a new modified quaternary ammonium silane irrigant solution for its antimicrobial, cytotoxic and mechanical properties of dentine substrate.

METHODS

Root canal preparation was performed using stainless steel K-files™ and F4 size protaper with irrigation protocols of 6% NaOCl + 2% CHX; 3.5% QIS; 2% QIS and sterile saline. Biofilms were prepared using E. faecalis adjusted and allowed to grow for 3 days, treated with irrigants, and allowed to grow for 7 days. AFM was performed and surface free energy calculated. MC3T3 cells were infected with endo irrigant treated E. faecalis biofilms. Raman spectroscopy of biofilms were performed after bacterial re-growth on root dentine and exposed to different irrigation protocols and collagen fibers analysed collagen fibers using TEM. Antimicrobial potency against E. faecalis biofilms and cytoxicity against 3T3 NIH cells were also. Resin penetration and MitoTracker green were also evaluated for sealer penetration and mitochondrial viability. Data were analysed using One-way ANOVA, principal component analysis and post-hoc Fisher's least-significant difference.

RESULTS

Elastic moduli were maintained amongst control (5.5 ± 0.9) and 3.5% QIS (4.4 ± 1.1) specimens with surface free energy higher in QIS specimens. MC3T3 cells showed reduced viability in 6%NaOCl+2%CHX specimens compared to QIS specimens. DNA/purine were expressed in increased intensities in control and 6% NaOCl + 2% CHX specimens with bands around 480-490 cm^-1 reduced in QIS specimens. 3.5% QIS specimens showed intact collagen fibrillar network and predominantly dead bacterial cells in confocal microscopy. 3.5% QIS irrigant formed a thin crust-type surface layer with cytoplasmic extensions of 3T3NIH spread over root dentine. Experiments confirmed MitoTracker accumulation in 3.5% treated cells.

SIGNIFICANCE

Novel QIS root canal irrigant achieved optimum antimicrobial protection inside the root canals facilitating a toxic effect against the Enterococcus faecalis biofilm. Root dentine substrates exhibited optimum mechanical properties and there was viability of fibroblastic mitochondria.

Are Antimicrobial Peptide Dendrimers an Escape from ESKAPE?

Significance: The crisis of antimicrobial resistance (AMR) increases dramatically despite all efforts to use available antibiotics or last resort antimicrobial agents. The spread of the AMR, declared as one of the most important health-related issues, warrants the development of new antimicrobial strategies. Recent Advances: Antimicrobial peptides (AMPs) and AMP dendrimers (AMPDs), as well as polymer dendrimers are relatively new and promising strategies with the potential to overcome drug resistance issues arising in ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) colonizing chronic wounds. Critical Issues: AMPs-AMPDs suffer from limited efficacy, short-lasting bioactivity, and concerns of toxicity. To circumvent these drawbacks, their covalent coupling to biopolymers and/or encapsulation into different drug carrier systems is investigated, with a special focus on topical applications. Future Directions: Scientists and the pharmaceutical industry should focus on this challenging subject to either improve the activity of existing antimicrobial agents or find new drug candidates. The focus should be put on the discovery of new drugs or the combination of existing drugs for a better synergy, taking into account all kinds of wounds and existing pathogens, and more specifically on the development of next-generation antimicrobial peptides, encompassing the delivery carrier toward improved pharmacokinetics and efficacy.

Comparative Evaluation of the Efficacy of Chlorhexidine, Sodium Hypochlorite, the Diode Laser and Saline in Reducing the Microbial Count in Primary Teeth Root Canals - An In Vivo Study

Introduction: One of the primary goals of pulpectomy is to decrease the sum total of microorganisms and disinfect the tooth root canal system. To achieve this, mechanical preparation, irrigation, disinfection and obturation of the root canal is necessary. The present study was set out to evaluate the difference in the antibacterial efficacy of primary teeth root canals either irrigated with chlorhexidine, saline, and sodium hypochlorite or irradiated with a soft tissue diode laser (980 nm, Photon Plus, Zolar Tech & Mfg Co. Inc, Ontario, Canada). Methods: Sixty primary teeth of children requiring pulpectomy were divided into 4 groups of 15 each, group 1 (2% chlorhexidine), group 2 (1% sodium hypochlorite), group 3 (laser irradiation) and group 4 (saline). Pulp tissue was extirpated from the canals and the samples were collected using sterile absorbent paper points. After cleaning and shaping, the root canals of the teeth in each group were irrigated using sodium hypochlorite, chlorhexidine, and saline or were irradiated with the laser. The samples were obtained again and sent for microbiological examination. Results: The colony-forming unit (CFU) counts from pre-disinfection sample served as a baseline for comparisons throughout the study. The mean bacterial colony counts of all the isolated bacteria reduced after irrigation or irradiation. Intergroup comparisons showed no significant difference when groups 1, 2, and 3 were compared to each other (P > 0.05). However, a significant difference was seen when groups 1, 2, 3 were compared to group 4 (P < 0.05). Conclusion: Two percent chlorhexidine, 1% sodium hypochlorite and laser irradiation succeeded in reducing the root canal infection. Hence, diode laser irradiation may be a possible supplement to existing protocols for disinfecting the root canal system.

Experimental Human Root Canal Irrigant NaOCl Against Enterococcus Faecalis and 3T3, and Determination of Cytotoxicity Effect

The main aim of endodontic treatment is disinfection of root canal and to prevent chances of reinfection. The most commonly isolated species due to oral infections is Enterococcus faecalis. For nonsurgical endodontic procedures Sodium hypochlorite (NaOCl) has been the irrigant of choice. The mechanism by which endodontic irrigants induce cytotoxicity is still unclear. However, many studies clearly indicated that rapid expression of the reactive oxygen species (ROS) leads to free radicals formation which results in cytotoxicity and cell death. Hence this study was done to determine the viability of cells and oxidative stress mediated by NaOCl, an endodontic irrigant. The irrigants were tested for their effect against fibroblast isolated from human primary buccal mucosa and against 3T3 Cell line. Antibacterial activity was performed against Enterococcus faecalis. Cytotoxicity was determined by MTT. To determine the oxidative stress, total intracellular glutathione, superoxide radical scavenging activity, and catalase assays were performed. The MIC (Minimal Inhibitory Concentration) for the irrigants against Enterococcus faecalis was found to be 10 µl. 10 µl of NaOCl plain 5.2% produced the same effect as that of 10 μl of NaOCl plain 3%. The higher concentration of the irrigants decreased viability of the cells during dye exclusion assay. Enzyme based study showed there is a decrease in enzyme dehydrogenase when treat with irrigants. Glutathione, SOD level was increased gradually on 3T3 cells. But CAT level was increased when the irrigants concentration less. The results of this study indicated that endodontic irrigants were potentially controlling the Enterococcus faecalis and non-toxic/reduced viability of 3T3 cells by MTT which could be due to the oxidative stress and loss of cellular integrity probably due to the liberation of ROS evidenced by the alteration of antioxidant enzymes Glutathione, SOD and CAT.

Flow Cytometry Analysis of Antibacterial Effects of Universal Dentin Bonding Agents on Streptococcus mutans

There is no consensus on the antibacterial activity of dentin bonding systems (DBS). Many study models have been used to evaluate the antimicrobial activity of dental materials. In this study, a novel detection method, flow cytometry, was introduced. It allows for evaluation of the antibacterial activity of DBS, based on assessment of the disruption of the bacterial physical membrane induced by DBS. The aim of the study was to evaluate the antibacterial properties of selected dentin bonding systems against Streptococcus mutans. The highest antibacterial activity against S. mutans was observed for Adhese Universal (99.68% dead cells) and was comparable to that of Prime&Bond Universal, OptiBond Universal, or Clearfil Universal Bond Quick (p > 0.05). The lowest activity of all tested systems was displayed by the multi-mode adhesive, Universal Bond (12.68% dead bacteria cells), followed by the self-etch adhesive, OptiBond FL (15.58% dead bacteria cells). The present study showed that in the case of two-component DBS, the primer exhibited higher antimicrobial activity than the adhesive (or bond) itself.

Influence of surfactants addition on the properties of calcium hypochlorite solutions

Objectives

The aim of this study was to evaluate the influence of surfactants 0.2% or 0.1% cetrimide (Cet) or 0.008% benzalkonium chloride (BAK) on 2.5% calcium hypochlorite (Ca(OCl)₂), and compare to sodium hypochlorite (NaOCl), regarding the properties of pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity.

Material and Methods

The pH and free chlorine content were evaluated by digital pHmeter and by titration, respectively. Surface tension was measured by the platinum ring technique with a Du Noüy tensiometer. The solution's contact angle in human dentin surfaces was checked by Drop Shape Analyzer software. Bovine pulps were used for pulp dissolution analysis and the dissolving capacity was expressed by percent weight loss. Antimicrobial activity over Enterococcus faecalis was evaluated by the agar diffusion method.

Results

Surfactants addition to Ca(OCl)₂ and NaOCl did not alter the pH, free chlorine content and pulp dissolution properties. Ca(OCl)₂ had the highest surface tension among all tested solutions. When surfactants were added to Ca(OCl)₂ and NaOCl, there was a significant reduction of surface tension and contact angle values. The addition of 0.2% or 0.1% Cet enhanced antimicrobial activity of both Ca(OCl)² and NaOCl.

Conclusion

Surfactant addition to 2.5% Ca(OCl)² has shown acceptable outcomes for pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Furthermore, the addition of 0.2% Cet showed better results for all tested properties.

Therapeutic benefits of liquorice in dentistry

Oral health influences general well-being and quality of life. Oral diseases can be debilitating and are a major heath concern worldwide. Medicinal plants have been used for thousands of years for treating human diseases. Considering the emergence of multi-drug resistant pathogens and financial difficulties in developing countries, there is an urgent need for developing new antimicrobial compounds which are safe, efficient and cost effective. Liquorice also known as yashtimadhu, sweetwood or mulhatti is one such herbal remedy which has shown to have immense potential in treatment of orofacial diseases. Liquorice is rich in secondary metabolites which are used in cosmetics, foods, traditional and modern medicine. It has well known properties such as antiviral, glucocorticoid, anti-inflammatory, antioxidant, anti-ulcerative, anti-carcinogenic and many more. Liquorice extracts and liquorice bioactive ingredients such as glabridin, licoricidin, licorisoflavan A, licochalcone A, and glycyrrhizin have shown beneficial effects in preventing and treating oral diseases. This paper reviews the effects of liquorice and its constituents on oral diseases such as dental caries, periodontitis, gingivitis, candidiasis, recurrent aphthous ulcer and oral cancer and its use as a root canal medicament and summarizes the results of clinical trials that investigated the potential beneficial effects of liquorice and its constituents as a prevention and treatment modality in oral diseases. Clinical trials, case reports and review of literature evaluating the effect of liquorice on oral microorganisms and oral diseases are included. Literature pertaining to the effects of liquorice on systemic diseases have been excluded from this review of literature.

Cytotoxicity Evaluation of Combination Irrigant Regimens with MTAD on Two Different Cell Lines

Background:

Effective management of smear layer ensures adequate clinical success. Use of sodium hypochlorite (NaOCl)/ethylenediaminetetraacetic acid regimen has been the gold standard with limitations. Commercial irrigants incorporate surface modifiers to address these drawbacks. The aim of this study was to evaluate the cytotoxicity of combination regimens on target and nontarget cell lines by trypan blue assay.

Materials and Methods:

Nonsurfactant combination regimen of chlorhexidine (CHX) and NaOCl (2% CHX + 2.5% NaOCl) and surfactant regimens of CHX with cetrimide (CTR) (2% CHX + 0.5% CTR) and CHX with sodium dodecyl sulfate (2% CHX + 1% SDS) were prepared. 0.9% normal saline (NS) and Biopure MTAD (100%) served as control. Cytotoxicity was evaluated on human gingival fibroblast (HGF) and Henrietta Lacks (HeLa) cell lines by trypan blue assay. Thirty microliter of the cell suspension was treated with 20 μl of irrigants. The cell suspension was loaded into Neubauer chamber after 5 min and cell count was performed under inverted microscope and expressed as viability percentage.

Results:

Nonsurfactant combination comprising of 2% CHX + 2.5% NaOCl formed a brownish precipitate while surfactant combination regimes were stable without any precipitate formation. NS and 2% CHX + 0.5% CTR had greater viability scores on both cell lines. Two percent CHX + 1% SDS had better viability on HeLa but were severely cytotoxic on HGF. Two percent CHX + 2.5% NaOCl and MTAD were found to be severely cytotoxic on HeLa with limited viability on HGF.

Conclusion:

The variation in data obtained could be possibly attributed to the difference in the cellular membrane composition and mechanism of action of combination regimens. Experimental surfactant regimen 2% CHX + 0.5% CTR shows lower cytotoxicity than MTAD.

Antibacterial Efficacy of Biosynthesized Silver Nanoparticles against Enterococcus faecalis Biofilm: An in vitro Study

Aim

This study aims to evaluate the antibacterial efficacy of biosynthesized silver nanoparticles (AgNPs) produced using the fungi against Enterococcus faecalis biofilm model on root dentin.

Materials and Methods

AgNPs were biosynthesized using the fungi Fusarium semitectum isolated from healthy leaves of Withania somnifera. Minimum inhibitory concentration (MIC) of AgNPs was determined by microbroth dilution method using series of dilutions. MIC dose was standardized to evaluate the antibacterial efficacy. For biofilm model, thirty root dentin blocks prepared using human extracted single-rooted teeth were inoculated with E. faecalis in Trypticase soy agar broth for 2 weeks with alternate day replenishment and randomly divided into three groups (n = 10 each) and treated as: Group I: Sterile distilled water, Group II: AgNPs, and Group III: 2% chlorhexidine gluconate (CHX) and incubated at 37°C for 24 h. Each dentin block was rinsed in saline, vortex shaken for 60 s, and serial decimal dilutions were prepared and plated on trypticase soy agar plates and incubated for 24 h followed by CFU colony counting and statistically analyzed using one-way ANOVA followed by post hoc Tukey honestly significant difference test.

Results

MIC of AgNPs for E. faecalis was determined as 30 mg/ml. No significant difference was seen between AgNPs and 2% CHX when compared to the control group with mean colony counts being 2.4, 2.5, and 6.77 CFU/ml (10⁷), respectively (P < 0.0001), against E. faecalis biofilm.

Conclusion

Biosynthesized AgNPs exhibit effective antimicrobial activity against E. faecalis biofilm on root dentin. Therefore, it can be employed as antimicrobial agent for root canal disinfection.

Evaluation of antibacterial efficacy of biosynthesized silver nanoparticles derived from fungi against endo-perio pathogens Porphyromonas gingivalis, Bacillus pumilus, and Enterococcus faecalis

Background

Even after rapid progress in contemporary dental practice, we encounter the failures due to endodontic, periodontal, or combined lesions. Complex anatomy of tooth and resistant microbes demands the development of new treatment strategies.

Aim

The aim of this study is to biosynthesize silver nanoparticles (AgNPs) using fungi and determine the antibacterial efficacy against Porphyromonas gingivalis, Bacillus pumilus, and Enterococcus faecalis.

Materials and Methods

Fungi isolated from healthy leaves of Withania somnifera were used to biosynthesize AgNPs. The biosynthesized AgNPs were characterized by different methods, and antibacterial efficacy was evaluated by agar well diffusion method measuring the zone of inhibition. Test microorganisms were divided as Group 1: B. pumilus 27142 (American Type Culture Collection [ATCC]), Group 2: E. faecalis 29212 (ATCC), and Group 3: P. gingivalis 33277 (ATCC). Agents used for antibacterial efficacy were grouped as: AgNPs: A (20 μl), B (40 μl), C (60 μl), D (80 μl), E (100 μl), F (0.2% chlorhexidine [CHX]), G (2% CHX), H (Ampicillin), and I (sterile distilled water).

Results

Characterization studies showed the color change from colorless to reddish brown color; ultraviolet spectrum showed peak at 420 nm, transmission electron microscope revealed the particles spherical in shape and 10-20 nm size. Fourier transform infrared spectroscopy analysis revealed the presence of functional groups. Data collected for antibacterial efficacy were analyzed using one-way ANOVA and post hoc Tukey's multiple shows no significant difference among three groups (P < 0.0001). AgNPs were as effective as CHX and positive control ampicillin. No zones were seen for I (distilled water).

Conclusion

Biosynthesized AgNPs showed efficient antibacterial efficacy. Therefore, it creates a new horizon in the management of endodontic, periodontal, and combined lesions.

Antimicrobial activity of root canal irrigants against biofilm forming pathogens- An in vitro study

Aims:

The aim of the study was to check the antimicrobial activity of the 5% Sodium hypochlorite, 2% Chlorhexidine, 0.10% Octenidine (OCT), and 2% Silver Zeolite (SZ) at different time intervals against a single species biofilm of Enterococcus faecalis, Staphylococcus aureus, and Candida albicans model prepared on a nitrocellulose membrane.

Settings and Design:

In vitro nitrocellulose biofilm model was used to check antibacterial efficacy of root canal irrigants.

Materials and Methods:

The in vitro nitrocellulose biofilm model was used to check the antibacterial activity of root canal irrigants. Single species biofilms were suspended into 96-well microtiter plate and treated with root canal irrigants for 1, 5, 10, 15, 30, and 60 s, respectively. The remaining microbial load in the form of colony-forming unit/ml after antimicrobial treatment was tabulated and data were statistically analyzed.

Statistical Analysis:

SPSS version 17, Kruskal–Wallis ANOVA, Mann–Whitney U-test, and Wilcoxon matched pair test (P < 0.05) were used.

Results:

All tested microorganisms were eliminated within 30 s by all the antimicrobial substances tested except normal saline. 2% chlorhexidine and 0.10% OCT were equally effective against C. albicans at 30 s.

Conclusion:

The newly tested irrigants have shown considerable antibacterial activity against selected single species biofilm. OCT (0.10%) can be used as an alternative endodontic irrigant.

Comparison of the Antimicrobial Efficacy of Octenidine Dihydrochloride and Chlorhexidine with and Without Passive Ultrasonic Irrigation - An Invitro Study

INTRODUCTION

Elimination of microorganisms from infected root canals is a complicated task. Numerous measures have been described to reduce the microbial load in the root canal system, including the use of various instrumentation techniques, irrigation regimens and intracanal medicaments. The drawbacks of few commonly used irrigants include toxic and harmful side effects, microbial resistance to antimicrobial agents and staining. Hence there is a need for alternative agents which are nontoxic, effective and safe.

AIM

To compare and evaluate antimicrobial effects of 2% Chlorhexidine (CHX) versus 0.1% Octenidine Dihydrochloride (OCT) as root canal irrigant with and without passive ultrasonic irrigation against Enterococcus faecalis (E. faecalis) in vitro and to evaluate the depth of penetration of irrigant solution into the dentinal tubules at the junction of middle and apical third.

MATERIALS AND METHODS

Forty eight freshly extracted, single rooted human mandibular premolars were decoronated and root specimen standardized to 14mm. Biofilm of E. faecalis (strain ATCC 29212) was grown for seven days and the specimens were divided into four groups (n=12) based on irrigation protocol : Group I- Conventional Syringe Irrigation (CSI) with 2% CHX, Group II- CSI + 0.1% OCT, Group III-Passive Ultrasonic Irrigation (PUI) + 2% CHX and Group IV- PUI+ 0.1% OCT. Dentin shavings were collected at two depths (200μm and 400μm) and total number of colony forming units were determined. The data were statistically analyzed using ANOVA, Scheffes multiple comparison of means and paired t-test (p<0.05).

RESULTS

Group III and IV (PUI) showed significant difference compared to Group I and II (CSI) both at 200μm and 400μm (p=0.000). For Group III and Group IV no significant differences were found at 200μm and 400μm (p=1.000 and 0.363 respectively), however significant difference was found between data at 200μm and 400μm for all the four groups (p=0.000).

CONCLUSION

Octenidine (0.1%) was more effective than 2% Chlorhexidine against E. faecalis both at 200μm and 400μm. Passive ultrasonic irrigation proved to enhance the antimicrobial action of the irrigants.

Evaluation of Antibacterial Efficacy of MTA with and without Additives Like Silver Zeolite and Chlorhexidine

INTRODUCTION

Microorganisms, predominantly Enterococcus faecalis are found responsible in the progression of pulpal, periradicular diseases and in endodontic failures. Unsuccessful conventional treatment might necessitate the need for a surgical approach; where in retrograde restorative materials are used to seal the apex. Among the root end filling materials, Mineral Trioxide Aggregate (MTA) is considered biocompatible and is most commonly used in clinical applications but it has limited antibacterial activity. Metallic silver and chlorhexidine have been added into various dental materials to enhance the antibacterial activity.

AIM

This study aimed to compare the antibacterial effect of MTA, MTA mixed with silver zeolite and MTA mixed with chlorhexidine against Enterococcus faecalis.

MATERIALS AND METHODS

Test materials used in the study were divided into three groups namely Group 1- MTA, Group 2-MTA + Silver Zeolite, Group 3-MTA + Chlorhexidine. Direct contact test was done by placing a standardized suspension of Enterococcus faecalis on the test materials in a 96 well microtiter plate. The bacterial growth was measured spectrophotometrically using ELISA reader at intervals of one, three and seven days.

STATISTICAL ANALYSIS

Data was collected by recording the optical density and analyzed using two-way ANOVA and Tukey's multiple post hoc test followed by paired-t test.

RESULTS AND CONCLUSION

All test groups showed antibacterial activity against Enterococcus faecalis at day one, three and seven. MTA with silver zeolite showed the maximum antibacterial activity followed by MTA with 2% chlorhexidine. The least antibacterial effect was shown by MTA mixed with sterile water.

Relationship between antibiotic- and disinfectant-resistance profiles in bacteria harvested from tap water

Chlorination is commonly used to control levels of bacteria in drinking water; however, viable bacteria may remain due to chlorine resistance. What is concerning is that surviving bacteria, due to co-selection factors, may also have increased resistance to common antibiotics. This would pose a public health risk as it could link resistant bacteria in the natural environment to human population. Here, we investigated the relationship between chlorine- and antibiotic-resistances by harvesting 148 surviving bacteria from chlorinated drinking-water systems and compared their susceptibilities against chlorine disinfectants and antibiotics. Twenty-two genera were isolated, including members of Paenibacillus, Burkholderia, Escherichia, Sphingomonas and Dermacoccus species. Weak (but significant) correlations were found between chlorine-tolerance and minimum inhibitory concentrations against the antibiotics tetracycline, sulfamethoxazole and amoxicillin, but not against ciprofloxacin; this suggest that chlorine-tolerant bacteria are more likely to also be antibiotic resistant. Further, antibiotic-resistant bacteria survived longer than antibiotic-sensitive organisms when exposed to free chlorine in a contact-time assay; however, there were little differences in susceptibility when exposed to monochloramine. Irrespective of antibiotic-resistance, spore-forming bacteria had higher tolerance against disinfection compounds. The presence of chlorine-resistant bacteria surviving in drinking-water systems may carry additional risk of antibiotic resistance.

In vitro comparison of antimicrobial effect of sodium hypochlorite solution and Zataria multiflora essential oil as irrigants in root canals contaminated with Candida albicans

INTRODUCTION

This study compared the antifungal effect of Zataria multiflora essential oil (EO) with that of sodium hypochlorite (NaOCl) as an irrigant for root canals infected with Candida albicans.

MATERIALS AND METHODS

Sixty mandibular premolars were infected with C. albicans suspension. After 72 h of incubation, the samples were divided into four groups. Teeth in Group 1 were irrigated with minimum fungicidal concentration (MFC) of Z. multiflora EO, in Group 2 with twice the MFC of Z. multiflora, in Group 3 with MFC of NaOCl, and in Group 4 with distilled water (DW). Pre- and post-operative samples were cultured, and fungal colony count of each specimen was obtained. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests (P < 0.05).

RESULTS

NaOCl at MFC and Z. multiflora EO at twice the MFC showed the highest antifungal efficacy, with no significant difference (P > 0.05). However, antifungal efficacies of these irrigants were significantly different from those of Z. multiflora EO at MFC and DW (P < 0.05).

CONCLUSION

Our results showed that Z. multiflora EO at twice the MFC had the same antifungal efficacy as NaOCl at MFC.

Effect of different final irrigating solutions on smear layer removal in apical third of root canal: A scanning electron microscope study

AIM

The aim of this in vitro study is to compare the smear layer removal efficacy of different irrigating solutions at the apical third of the root canal.

MATERIALS AND METHODS

Forty human single-rooted mandibular premolar teeth were taken and decoronated to standardize the canal length to 14 mm. They were prepared by ProTaper rotary system to an apical preparation of file size F3. Prepared teeth were randomly divided into four groups (n = 10); saline (Group 1; negative control), ethylenediaminetetraacetic acid (Group 2), BioPure MTAD (Group 3), and QMix 2 in 1 (Group 4). After final irrigation with tested irrigants, the teeth were split into two halves longitudinally and observed under a scanning electron microscope (SEM) for the removal of smear layer. The SEM images were then analyzed for the amount of smear layer present using a three score system.

STATISTICAL ANALYSIS

Data are analyzed using the Kruskal-Wallis test and Mann-Whitney U-test.

RESULTS

Intergroup comparison of groups showed statistically significant difference in the smear layer removal efficacy of irrigants tested. QMix 2 in 1 is most effective in removal of smear layer when compared to other tested irrigants.

CONCLUSION

QMix 2 in 1 is the most effective final irrigating solution for smear layer removal.

Viscosity of endodontic irrigants: Influence of temperature

BACKGROUND

The aim of this study was to assess the influence of temperature on the viscosity of different endodontic irrigants.

MATERIALS AND METHODS

The measurements of viscosity of 3% hydrogen peroxide, 0.9% sodium chloride, aqueous solution of 0.2% chlorhexidine (CHX) and 0.2% cetrimide, 5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) at different temperatures (22°C, 30°C, 40°C, 50°C and 60°C) were obtained using Mohr balance and Ostwald viscometer. The Shapiro-Wilk test and Mann-Whitney U-tests were used for the statistical analysis. (α = 0.05).

RESULTS

No significant differences were recorded at each temperature among 3% hydrogen peroxide, 0.9% sodium chloride and aqueous solution of 0.2% CHX and 0.2% cetrimide. 5% NaOCl and 17% EDTA showed the higher values. Viscosity statistically decreased with increasing temperature.

CONCLUSION

Within the limitations of this study, 5% NaOCl and 17% EDTA are significantly viscous at room temperature and their viscosity reduces with elevating temperature.

Assessment of the Potential of CFC (Calcium hydroxide Flagyl Ciprofloxacin) for the Rapid Disinfection of Resilon and Gutta-Percha

INTRODUCTION

Obturating materials exposed to the dental operating environment has been shown to be contaminated, making rapid chair side disinfection mandatory to ensure the sterility of the root canals.

OBJECTIVE

The purpose of this study was to investigate the effectiveness of CFC (combination of Calcium hydroxide, Flagyl and Ciprofloxacin) for the rapid disinfection of Gutta-percha and Resilon cones.

MATERIALS AND METHODS

Seventy new Gutta-percha and Resilon cones were randomly selected, contaminated with Enterococcus faecalis and divided into 4 group according to the irrigant used for disinfection {Group I: 5.25% Sodium Hypochlorite (NaOCl), Group II: MTAD, Group III: 2% Chlorhexidine (CHX), Group IV: CFC (a combination of Calcium hydroxide, Flagyl and Ciprofloxacin)}. All the samples were placed in a centrifuge tube with BHI broth after being washed with sterile water. The samples were then incubated for 7 days at 37(o)C. Samples were randomly plated on Mac Conkey agar plate and the colony count was recorded and the observations were drawn.

RESULTS

A 5.25% NaOCl required 1 minute exposure for effective disinfection of all the samples. MTAD could eliminate E.faecalis from gutta-percha samples in 30 seconds whereas it required 1 minute of exposure for Resilon cones. Both 2% CHX and CFC could not disinfect the samples with 1 minute exposure and a minimum of 5 minute exposure was required.

CONCLUSION

A 5.25% NaOCl and Biopure MTAD required less chair side time to disinfect all the samples effectively when compared with 2% CHX and CFC.

Comparison of Different Irrigants in the Removal of Endotoxins and Cultivable Microorganisms from Infected Root Canals

This study was conducted to compare the effectiveness of different irrigants used to remove endotoxins and cultivable microorganisms during endodontic therapy. Forty root canals were contaminated and divided into groups according to the irrigant: 2% NaOCl + surfactant, 2% CHX, 2.5% NaOCl, and pyrogen-free saline solution (control). Samples were collected after root canal contamination (S1), after instrumentation (S2), and 7 days after instrumentation (S3). Microorganisms and endotoxins were recovered from 100% of the contaminated root canals (S1). At S2, 2% NaOCl + surfactant, 2% CHX, and 2.5% NaOCl were able to completely eliminate cultivable microorganisms. At S3, both 2% CHX and 2.5% NaOCl were effective in preventing C. albicans and E. coli regrowth, but E. faecalis was still detected. No microorganism species was recovered from root canals instrumented with 2% NaOCl + surfactant. At S2, a higher percentage value of endotoxin reduction was found for 2% NaOCl + surfactant (99.3%) compared to 2% CHX (98.9%) and 2.5% NaOCl (97.18%) (p < 0.05). Moreover, at S3, 2% NaOCl + surfactant (100%) was the most effective irrigant against endotoxins. All irrigants tested were effective in reducing microorganisms and endotoxins from root canals. Moreover, 2% NaOCl + surfactant was the most effective irrigant against endotoxins and regrowth of microorganisms.

Viability and antibacterial efficacy of four root canal disinfection techniques evaluated using confocal laser scanning microscopy

Background:

Several disinfection techniques have been recently introduced with the main objective of improving root canal disinfection in the inaccessible areas of the root canal system. This in vitro study was done to evaluate the antimicrobial effect and viability of Enterococcus faecalis biofilms using conventional irrigation, EndoActivator (Dentsply, Tulsa Dental, USA), diode laser irradiation and photon-initiated photoacoustic streaming (PIPS).

Materials and Methods:

Root canals of 130 single rooted mandibular premolars, standardized to a uniform length of 20 mm were instrumented until finishing file, F1 (Universal Protaper Rotary System, Dentsply, Tulsa Dental Specialties, USA). After smear layer removal and sterilization, five teeth were randomly selected to assure sterility before bacterial inoculation. The remaining 125 samples were contaminated with E. faecalis suspension, incubated for 21 days and divided into five groups (n = 25). In Group 1; untreated group (positive control), the root canals were not subjected to any disinfection procedure. Sampling was performed within the canals and the colony-forming unit count was evaluated for 20 samples. Five samples were selected to visualize the pattern of colonization at Level 1 (4 mm from the apex) and Level 2 (1 mm from the apex) by confocal laser scanning microscopy. Samples in Groups 2-5 namely conventional needle irrigation, EndoActivator, diode laser and PIPS were subjected to their respective disinfection procedures. Postdisinfection sample evaluation criteria was followed for all groups as same as that for Group 1.

Results:

Diode laser displayed the highest antibacterial efficacy and least viable bacteria than the other three disinfection techniques.

Conclusion:

Diode laser group showed better antibacterial efficacy and least viable bacteria when compared to conventional needle irrigation, PIPS and EndoActivator groups in minimally instrumented, experimentally infected root canals.

Effect of addition of 2% chlorhexidine or 10% doxycycline on antimicrobial activity of biodentine

Aim:

The purpose of this in vitro study was to determine whether the addition of 2% chlorhexidine gluconate or 10% doxycycline would enhance the antimicrobial activity of Biodentine against Staphylococcus aureus (ATCC-25923), Enterococcus faecalis (ATCC-29212), Candida albicans (ATCC-90028), and Streptococcus mutans (MTCC-497).

Materials and Methods:

Three wells of 4 mm diameter and 4 mm depth on each plate were prepared on the agar medium with standardized suspensions of each microorganism. Biodentine powder mixed with 2% chlorhexidine (0.06 g) or 10% doxycycline (0.30 g) in its liquid or liquid alone was placed to fill each well. Plates were incubated at 37°C as required for microbial growth. A blinded, independent observer measured zones of inhibition. The data were analyzed using independent “t” test to compare the differences among the three cement preparations for different micro-organisms.

Results:

All Biodentine samples inhibited microbial growth. The highest mean diameters of zone of inhibition for all the micro-organisms were found around Biodentine/chlorhexidine (13.417) followed by Biodentine alone (12.236) and Biodentine/doxycycline (11.25).

Conclusion:

In conclusion, adding 2% chlorhexidine gluconate in liquid of Biodentine enhanced the antimicrobial activity of Biodentine against all the tested micro-organisms except Candida albicans, while addition of 10% doxycycline decreased the antimicrobial activity of Biodentine. The differences were significant statistically (P < 0.05).

Influence of temperature and concentration on the dynamic viscosity of sodium hypochlorite in comparison with 17% EDTA and 2% chlorhexidine gluconate: An in vitro study

Aims:

The aim of this study was to assess the influence of temperature and concentration on the dynamic viscosity of sodium hypochlorite in comparison with 17% EDTA and 2% chlorhexidine gluconate.

Settings and Design:

In vitro

Materials and Methods:

Dynamic viscosity measurements of sodium hypochlorite [NaOCl (5.25%, 2.6%, 1.25%)], EDTA (17%), and chlorhexidine gluconate [CHX, 2%] were measured using a rotational digital viscometer at room temperature (25°C). The influence of temperature (45°C, 60°C) and concentration (5.25%, 2.6%, and 1.25%) on the dynamic viscosity of NaOCl was also evaluated. The measurements were performed using a circulating water bath calibrated with a thermostat, and the dynamic viscosity measurements were noted in Centipoise (Cps).

Statistical Analysis Used:

The tests used for the statistical analysis were Kolmogorov-Smirnov and Shapiro Wilk tests, one-way ANOVA, and independent sample t-test.

Results:

Viscosity statistically increased with NaOCl concentration and decreased with increasing temperature. Amongst the tested NaOCl groups, 5.25% NaOCl at room temperature was significantly the most viscous (μ =1.5300 Cps) while 1.25% NaOCl at 60°C was significantly the least viscous (μ =1.1800 Cps).

Conclusions:

5.25% NaOCl and 17% EDTA are significantly viscous at room temperature. Elevating the temperature of 1.25% NaOCl to 60°C significantly reduces the viscosity of the NaOCl.