Association of Enterococcus faecalis with different forms of periradicular diseases

Effects of the irrigation needle design on root canal disinfection and cleaning

INTRODUCTION

This ex vivo study evaluated the disinfecting and cleaning effects of root canal preparation using NaOCl irrigation with three different needle designs.

METHODS

Mesial roots from extracted mandibular molars with Vertucci class II configuration were anatomically matched based on micro-computed tomography (micro-CT) analyses and distributed into three groups (n=18/group). The canals were contaminated with a mixed bacterial culture for 30 days and then subjected to preparation using 2.5% NaOCl irrigation with open-ended flat needle (3 mm short of the working length - WL), closed-ended side-vented irrigation needle (1 mm short of the WL) or a closed-ended plastic needle with two lateral outlets (TruNatomy) (1 mm short of the WL). Bacteriological samples were taken from the canals before (S1) and after preparation (S2). After another micro-CT scan, the roots were sectioned and samples were also taken from the apical canal segment (S3). Bacterial reduction was assessed by quantitative real-time polymerase chain reaction (qPCR). The amount of accumulated hard tissue debris was evaluated by micro-CT.

RESULTS

A substantial reduction in bacterial counts was observed in all three groups when comparing S1 with S2 (99.95%, 98.93%, and 98.90% in the open-ended, closed-ended, and TruNatomy needle groups, respectively) (P < 0.01). No significant differences were observed between groups for bacterial reduction in the full and apical canal (P > 0.05). There were no intergroup differences in the amount of accumulated hard tissue debris either (P > 0.05). The open-ended needle group showed significantly more specimens with qPCR negative results for bacteria in S3 than TruNatomy (P < 0.05).

CONCLUSION

When used up to an appropriate insertion depth, the three needle types result in similar antibacterial and cleaning performance, provided variables such as needle size and irrigant type, volume and flow rate are controlled. Exclusive analysis of the apical segment, including the isthmus, revealed that the open-ended needle yielded more cases negative for bacteria.

Is SWEEPS better than PUI in reducing intracanal bacteria and inflammation in cases of apical periodontitis?

To evaluate the efficacy of SWEEPS mode of the Er: YAG laser(SL) and passive ultrasonic irrigation(PUI) in the eradication of microorganisms and in the inflammation detection by IL-1β. Thirty patients with chronic apical periodontitis(AP) were allocated into two groups: Group SL-SWEEPS laser activated irrigation(n = 15) and Group PUI-passive ultrasonic irrigation(n = 15). Bacteriological samples were taken before(S1) and after chemomechanical preparation(S2), and then after final irrigation activation(S3). The levels of total bacteria and Streptococci were measured by means of PCR. Blood samples were collected before and 3rd day after treatment. Enzyme-linked immunosorbent assay was used to measure the levels of IL-1β. The bacterial reduction showed no differences between groups after chemo-mechanical treatment and after irrigant activation(p = 0.590). Post-treatment IL-1β levels were lower than pretreatment levels in both groups(p < 0.001). SL or PUI application in addition to chemomechanical preparation has similar effects on total bacterial level and inflammation detected by IL-1β in patients with AP.

Mining the Biosynthetic Landscape of Lactic Acid Bacteria Unearths a New Family of RiPPs Assembled by a Novel Type of ThiF-like Adenylyltransferases

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are chemically diverse natural products of ribosomal origin. These peptides, which frequently act as signals or antimicrobials, are biosynthesized by conserved enzymatic machinery, making genome mining a powerful strategy for unearthing previously uncharacterized members of their class. Herein, we investigate the untapped biosynthetic potential of Lactobacillales (i.e., lactic acid bacteria), an order of Gram-positive bacteria closely associated with human life, including pathogenic species and industrially relevant fermenters of dairy products. Through genome mining methods, we systematically explored the distribution and diversity of ThiF-like adenylyltransferase-utilizing RiPP systems in lactic acid bacteria and identified a number of unprecedented biosynthetic gene clusters. In one of these clusters, we found a previously undescribed group of macrocyclic imide biosynthetic pathways containing multiple transporters that may be involved in a potential quorum sensing (QS) system. Through in vitro assays, we determined that one such adenylyltransferase specifically catalyzes the intracyclization of its precursor peptide through macrocyclic imide formation. Incubating the enzyme with various primary amines revealed that it could effectively amidate the C-terminus of the precursor peptide. This new transformation adds to the growing list of Nature's peptide macrocyclization strategies and expands the impressive catalytic repertoire of the adenylyltransferase family. The diverse RiPP systems identified herein represent a vast, unexploited landscape for the discovery of a novel class of natural products and QS systems.

Exploring Plant-Based Compounds as Alternatives for Targeting Enterococcus faecalis in Endodontic Therapy: A Molecular Docking Approach

Endodontic infections pose significant challenges in dental practice due to their persistence and potential complications. Among the causative agents, Enterococcus faecalis stands out for its ability to form biofilms and develop resistance to conventional antibiotics, leading to treatment failures and recurrent infections. The urgent need for alternative treatments arises from the growing concern over antibiotic resistance and the limitations of current therapeutic options in combating E. faecalis-associated endodontic infections. Plant-based natural compounds offer a promising avenue for exploration, given their diverse bioactive properties and potential as sources of novel antimicrobial agents. In this study, molecular docking and dynamics simulations are employed to explore the interactions between SrtA, a key enzyme in E. faecalis, and plant-based natural compounds. Analysis of phytocompounds through molecular docking unveiled several candidates with binding energies surpassing that of the control drug, ampicillin, with pinocembrin emerging as the lead compound due to its strong interactions with key residues of SrtA. Comparative analysis with ampicillin underscored varying degrees of structural similarity among the study compounds. Molecular dynamics simulations provided deeper insights into the dynamic behavior and stability of protein-ligand complexes, with pinocembrin demonstrating minimal conformational changes and effective stabilization of the N-terminal region. Free energy landscape analysis supported pinocembrin's stabilizing effects, further corroborated by hydrogen bond analysis. Additionally, physicochemical properties analysis highlighted the drug-likeness of pinocembrin and glabridin. Overall, this study elucidates the potential anti-bacterial properties of selected phytocompounds against E. faecalis infections, with pinocembrin emerging as a promising lead compound for further drug development efforts, offering new avenues for combating bacterial infections and advancing therapeutic interventions in endodontic practice.

Triton X-100 counteracts antibiotic resistance of Enterococcus faecalis: An in vitro study

OBJECTIVES

The high prevalence of antibiotic-resistant bacteria poses a threat to the global public health. The appropriate use of adjuvants to restore the antimicrobial activity of antibiotics against resistant bacteria could be an effective strategy for combating antibiotic resistance. In this study, we investigated the counteraction of Triton X-100 (TX-100) and the mechanisms underlying the antibiotic resistance of Enterococcus faecalis (E. faecalis).

METHODS

Standard, wild-type (WT), and induced antibiotic-resistant E. faecalis strains were used in this study. In vitro antibacterial experiments were conducted to evaluate the antimicrobial activities of gentamicin sulfate and ciprofloxacin hydrochloride in the presence and absence of 0.02 % TX-100 against both planktonic and biofilm bacteria. Transcriptomic and untargeted metabolomic analyses were performed to explore the molecular mechanisms of TX-100 as an antibiotic adjuvant. Additionally, membrane permeability, membrane potential, glycolysis-related enzyme activity, intracellular adenosine triphosphate (ATP), and expression levels of virulence genes were assessed. The biocompatibility of different drug combinations was also evaluated.

RESULTS

A substantially low TX-100 concentration improved the antimicrobial effects of gentamicin sulfate or ciprofloxacin hydrochloride against antibiotic-resistant E. faecalis. Mechanistic studies demonstrated that TX-100 increased cell membrane permeability and dissipated membrane potential. Moreover, antibiotic resistance and pathogenicity of E. faecalis were attenuated by TX-100 via downregulation of the ABC transporter, phosphotransferase system (PTS), and ATP supply.

CONCLUSIONS

TX-100 enhanced the antimicrobial activity of gentamicin sulfate and ciprofloxacin hydrochloride at a low concentration by improving antibiotic susceptibility and attenuating antibiotic resistance and pathogenicity of E. faecalis.

CLINICAL SIGNIFICANCE

These findings provide a theoretical basis for developing new root canal disinfectants that can reduce antibiotic resistance.

Nanoarchitectonics-Based Materials as a Promising Strategy in the Treatment of Endodontic Infections

Endodontic infections arise from the interactive activities of microbial communities colonizing in the intricate root canal system. The present study aims to update the latest knowledge of nanomaterials, their antimicrobial mechanisms, and their applications in endodontics. A detailed literature review of the current knowledge of nanomaterials used in endodontic applications was performed using the PubMed database. Antimicrobial nanomaterials with a small size, large specific surface area, and high chemical activity are introduced to act as irrigants, photosensitizer delivery systems, and medicaments, or to modify sealers. The application of nanomaterials in the endodontic field could enhance antimicrobial efficiency, increase dentin tubule penetration, and improve treatment outcomes. This study supports the potential of nanomaterials as a promising strategy in treating endodontic infections.

Prevalence and virulence factors of haemolytic Enterococcus faecalis isolated from root filled teeth associated with periradicular lesions: A laboratory investigation in Thailand

AIM

Previous endodontic research has provided limited understanding of the prevalence and roles of haemolytic and non-haemolytic Enterococcus faecalis strains in root filled teeth. This study aimed to determine the prevalence of these strains in root filled teeth with periradicular lesions and investigate their associated virulence factors.

METHODOLOGY

A total of 36 root canal samples were collected from 36 subjects. The prevalence of E. faecalis was determined using culture and PCR methods. Antibiotic susceptibility of haemolytic and non-haemolytic E. faecalis strains was assessed using the broth dilution assay. The cytokine stimulation in periodontal ligament (PDL) cells and neutrophil migration were evaluated using real-time PCR and migration assay, respectively. Cell invasion ability of the strains was assessed using a cell culture model. Additionally, the virulence gene expression of the haemolytic and non-haemolytic strains was investigated using real-time PCR. The Mann-Whitney U and Spearman's ρ tests were used to examine the significant difference between the two strains and to analyse the correlation between phenotype and gene expression, respectively.

RESULTS

Enterococcus faecalis was detected in 33.3% and 88.9% of samples by culture and real-time PCR, respectively. Haemolytic strains were found in 36.4% of subjects. Non-haemolytic strains exhibited susceptibility to erythromycin and varying susceptibility to tetracycline, while all haemolytic strains were resistant to both antibiotics. Haemolytic strains significantly upregulated the expression of IL-8, OPG and RANKL in PDL cells (p < .05). Notably, the fold increases in these genes were higher: IL-8 (556.1 ± 82.9 vs. 249.6 ± 81.8), OPG (2.2 ± 0.5 vs. 1.3 ± 0.2) and RANKL (1.8 ± 0.3 vs. 1.2 ± 0.1). Furthermore, haemolytic strains had a greater effect on neutrophil migration (68.7 ± 15.2% vs. 46.9 ± 11.4%) and demonstrated a higher level of internalization into oral keratinocyte cells (68.6 ± 0.4% vs. 33.8 ± 0.5%) (p < .05). They also showed enhanced expression of virulence genes associated with haemolysin, surface proteins, collagen-binding and aggregation substances. Gelatinase activity was only detectable in non-haemolytic strains.

CONCLUSIONS

This study revealed that haemolytic strains E. faecalis possessed enhanced abilities in host invasion and a higher abundance of virulence factors, suggesting their potential contribution to more severe disease manifestations.

An in vitro evaluation of endodontic sealers and an antibiotic to assess their antimicrobial effect against Enterococcus faecalis

Objective

This study aimed to compare the antimicrobial effect of three endodontic sealers (AH Plus, Mineral trioxide aggregate [MTA] Fillapex, and BioRoot RCS) with and without amoxicillin against E. faecalis.

Methodology

Amoxicillin, equivalent to 10% of the sealers' total weight, was mixed with the sealers. Another batch was prepared without amoxicillin. The direct contact test (DCT) and the agar diffusion test were used to assess the antibacterial effect. Results were analysed using one-way analysis of variance (ANOVA), the F-test, and the Kruskal-Wallis test.

Results

AH Plus significantly suppressed E. faecalis without the addition of amoxicillin in the DCT (p = 0.011), while in the agar diffusion test, BioRoot RCS had a larger inhibition zone than the control (p < 0.001). When amoxicillin was added to the sealers, AH Plus (p = 0.003) and MTA Fillapex (p = 0.042) reduced E. faecalis growth. In contrast, all three sealers showed larger inhibition zones than the control (p = 0.001), with AH Plus displaying a larger inhibition zone than MTA Fillapex (p = 0.042) and BioRoot RCS (p = 0.032).

Conclusions

It was thus concluded that the addition of amoxicillin to endodontic sealers enhances their antimicrobial activity against E. faecalis.

"Magnet" Based on Activated Silver Nanoparticles Adsorbed Bacteria to Predict Refractory Apical Periodontitis Via Surface-Enhanced Raman Scattering

Refractory apical periodontitis (RAP) is an endodontic apical inflammatory disease caused by Enterococcus faecalis (E. faecalis). Bacterial detection using surface-enhanced Raman scattering (SERS) technology is a hot research topic, but the specific and direct detection of oral bacteria is a challenge, especially in real clinical samples. In this paper, we develop a novel SERS-based green platform for label-free detection of oral bacteria. The platform was built on silver nanoparticles with a two-step enhancement way using NaBH4 and sodium (Na+) to form "hot spots," which resulted in an enhanced SERS fingerprint of E. faecalis with fast, quantitative, lower-limit, reproducibility, and stability. In combination with machine learning, four different oral bacteria (E. faecalis, Porphyromonas gingivalis, Streptococcus mutans, and Escherichia coli) could be intelligently distinguished. The unlabeled detection method emphasized the specificity of E. faecalis in simulated saliva, serum, and even real samples from patients with clinical root periapical disease. In addition, the assay has been shown to be environmentally friendly and without secondary contamination through antimicrobial assays. The proposed label-free, rapid, safe, and green SERS detection strategy for oral bacteria provided an innovative solution for the early diagnosis and prevention of RAP and other perioral diseases.

Antibacterial biofilm efficacy of calcium hydroxide loaded on Gum Arabic nanocarrier: an in-vitro study

BACKGROUND

An innovative intracanal medication formulation was introduced in the current study to improve the calcium hydroxide (Ca(OH)2) therapeutic capability against resistant Enterococcus faecalis (E. faecalis) biofilm. This in-vitro study aimed to prepare, characterize, and evaluate the antibacterial efficiency of Ca(OH)2 loaded on Gum Arabic (GA) nanocarrier (Ca(OH)2-GA NPs) and to compare this efficiency with conventional Ca(OH)2, Ca(OH)2 nanoparticles (NPs), GA, and GA NPs.

MATERIALS AND METHODS

The prepared nanoparticle formulations for the tested medications were characterized using Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). 141 human mandibular premolars were selected, and their root canals were prepared. Twenty-one roots were then sectioned into 42 tooth slices. All prepared root canals (n = 120) and teeth slices (n = 42) were divided into six groups according to the intracanal medication used. E. faecalis was inoculated in the samples for 21 days to form biofilms, and then the corresponding medications were applied for 7 days. After medication application, the residual E. faecalis bacteria were assessed using CFU, Q-PCR, and SEM. Additionally, the effect of Ca(OH)2-GA NPs on E. faecalis biofilm genes (agg, ace, and efaA) was investigated using RT-PCR. Data were statistically analyzed at a 0.05 level of significance.

RESULTS

The synthesis of NPs was confirmed using TEM. The results of the FTIR proved that the Ca(OH)2 was successfully encapsulated in the GA NPs. Ca(OH)2-GA NPs caused a significant reduction in the E. faecalis biofilm gene expression when compared to the control (p < 0.001). There were significant differences in the E. faecalis CFU mean count and CT mean values between the tested groups (p < 0.001) except between the Ca(OH)2 and GA CFU mean count. Ca(OH)2-GA NPs showed the least statistical E. faecalis mean count among other groups. SEM observation showed that E. faecalis biofilm was diminished in all treatment groups, especially in the Ca(OH)2-GA NPS group when compared to the control group.

CONCLUSIONS

Ca(OH)2 and GA nanoparticles demonstrate superior anti-E. faecalis activity when compared to their conventional counterparts. Ca(OH)2-GA NPs showed the best antibacterial efficacy in treating E. faecalis biofilm. The tested NP formulations could be considered as promising intracanal medications.

Evaluation of the Effectiveness of Disinfectants on Impression Materials

Background The disinfection of dental impression materials is a cornerstone of infection control in dental practice. This study aimed to evaluate the effectiveness of two disinfectants, sodium hypochlorite and iodophor, on alginate and silicone impression materials, which are prone to microbial contamination. Methods The study was structured into two main groups based on the impression material: Group I (alginate) and Group II (addition silicone), each further subdivided into two subgroups for disinfection with sodium hypochlorite and iodophor. For each subgroup, initial microbial swabs were taken before any treatment, followed by a second swab after rinsing and a final swab after disinfection. The mean colony-forming unit (CFU) counts, standard deviations, and standard errors of the mean were calculated for each stage of treatment. Results Prior to disinfection, Group I had a mean CFU count of 2,529.40, while Group II had a lower mean CFU of 1,417.40. After rinsing, there was a significant decrease in CFUs in both groups, with Group I at 1,337.10 and Group II at 415.10. Post-disinfection, Group I showed a mean CFU count of 73.00 for sodium hypochlorite and 0.00 for iodophor. Similarly, Group II achieved a CFU reduction of 99.00 with sodium hypochlorite and 0.00 with iodophor, demonstrating a marked reduction in microbial presence. Conclusion Iodophor was exceptionally effective in disinfecting both alginate and silicone impression materials, eliminating all detectable CFUs. Sodium hypochlorite also significantly reduced microbial counts but was not as effective as iodophor. Rinsing prior to disinfection was instrumental in reducing the microbial load, underscoring its importance in the disinfection protocol.

The Presence of Four Pathogenic Oral Bacterial Species in Six Wild Snake Species from Southern Taiwan: Associated Factors

The oral cavity of snakes serves as a habitat for various microorganisms, some of which may include potential zoonotic pathogens posing risks to hosts and causing wound infections in snakebite victims. Clinical studies on snakebite cases in Taiwan have identified specific pathogens, such as Enterococcus faecalis (Gram-positive), Morganella morganii, Aeromonas hydrophila, and Pseudomonas aeruginosa (Gram-negative). However, the prevalence of these bacteria in the oral cavity of wild snakes remains largely unknown. This study investigated the occurrence of these bacteria in six wild snake species (Naja atra, Bungarus multicinctus, Trimeresurus stejnegeri, Protobothrops mucrosquamatus, Boiga kraepelini, and Elaphe taeniura friesi) from southern Taiwan, along with factors influencing their presence. Oropharyngeal swab samples were collected from a substantial number of wild-caught snakes (n = 1104), followed by DNA extraction, polymerase chain reaction, and gel electrophoresis. The band positions of samples were compared with positive and negative controls to determine the presence of target bacteria in each sample. The overall occurrence rates were 67.4% for E. faecalis, 31.5% for M. morganii, 8.2% for A. hydrophila, and 7.7% for P. aeruginosa. Among snake species, B. kraepelini exhibited dominance in E. faecalis (93.4%), A. hydrophila (17.1%), and P. aeruginosa (14.5%), while male N. atra showed dominance in M. morganii (51.3%). The occurrence of E. faecalis was lowest in winter. The results of multiple logistic regression analyses suggest that factors such as species, sex, temperature, season, and coexisting pathogens may have a significant impact on the occurrence of target bacteria. These findings have implications for wildlife medicine and snakebite management.

Effectiveness of continuous chelation irrigation protocol in endodontics: a scoping review of laboratory studies

This scoping review aimed to synthesize and explore the current boundaries and limitations of laboratory research on the effectiveness of continuous chelation irrigation protocol in endodontics. This scoping review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews. Literature search was conducted on Pubmed and Scopus to identify all laboratory studies evaluating smear layer and hard-tissue debris removal or, antimicrobial efficacy, or dentine erosion induced by continuous chelation. Two independent reviewers performed the all review steps and the relevant items were recorded. Seventy-seven potentially relevant studies were identified. Finally, 23 laboratory studies met the eligibility criteria for qualitative synthesis. Seven studies focused on the smear layer/debris removal outcome, 10 on antimicrobial activity, and 10 on dentine erosion. In general, the continuous chelation protocol was equally or more effective in the cleanliness of root canals and antimicrobial activity compared with traditional sequential protocol. In addition, etidronate solutions seemed to be milder chelating agents compared to those with EDTA, thus resulting in reduced or no dentine erosion and roughness modification. Yet, the methodological differences among the included studies limit the results' generalizability. The continuous chelation seems to be equally or more effective in all investigated outcomes when compared with the traditional sequential protocol. The methodological variability among the studies and shortcomings in the methods employed limit the generalizability and clinical relevance of the results. Standardized laboratory conditions combined with reliable three-dimensional investigation approaches are necessary to obtain clinically informative findings.

Complete genome assembly of Enterococcus faecalis strain HL1, isolated from an infant fecal sample

We present the complete genome sequence of Enterococcus faecalis strain HL1, isolated from infant feces. E. faecalis gains significant attention for its therapeutic potential. The genome of E. faecalis HL1 consists of a 2.7 Mb circular chromosome with no plasmids, and it contains a total of 2,546 predicted coding genes.

Efficacy of Triple Antibiotic Paste and Bromelain Paste As Intracanal Medicament Against Enterococcus faecalis: An In-Vivo Study

Introduction Microorganisms are pivotal contributors to pulp and periapical pathology, often culminating in endodontic treatment failures. The successful outcome of such treatment hinges on the effective eradication of microbial flora through various interventions, including intracanal medicaments (ICMs). However, Enterococcus faecalis (E. faecalis), a highly adaptive Gram-positive bacterium, exhibits remarkable resilience and can persist even after rigorous disinfection efforts. This study explores the efficacy of two ICMs, calcium hydroxide-based triple antibiotic paste (TAP) and a novel alternative containing bromelain, derived from pineapples, in combating E. faecalis infections in vivo. Methodology This in-vivo study was conducted at Sharad Pawar Dental College and Hospital, Wardha, India, and ethical approval was obtained from the institutional ethical committee. The sample size was calculated using the OpenEpi program (version 3.04.04, Open Source Epidemiologic Statistics for Public Health, www.OpenEpi.com), resulting in 15 participants per group. Inclusion criteria encompassed mandibular premolars with carious involvement but no prior restorations, diagnosed with necrotic or infected pulp, and no significant medical history. Exclusion criteria included systemic conditions, pregnancy, retreatment cases, recent antibiotic therapy, calcified canals, and other contraindications. After proper patient consent, access opening and chemomechanical preparation were performed, and root canals (RCs) were randomly divided into two groups: TAP and bromelain paste (BP). TAP was prepared using ciprofloxacin, metronidazole, and minocycline, while BP comprised bromelain powder mixed with saline. Both groups received intracanal medicaments, followed by temporary sealing. Microbiological samples were collected before and after treatment for analysis. Results E. faecalis count (CFU/mL) before instrumentation for the TAP group was (1.94 x 105 [Formula: see text] 7.45 x 103) and for BP group was (1.97 x 105 [Formula: see text] 7.70 x 103) with p-value 0.26 [Formula: see text] p=0.05, so no significant difference was found between them. E. faecalis count (CFU/mL) after instrumentation for the TAP group was (7.70 x 103 [Formula: see text] 9.11 x 102) and for the BP group was (7.26 x 103 [Formula: see text] 8.43 x 102) with p-value 0.18 [Formula: see text] p=0.05, so no significant difference was found between them. However, the E. faecalis count obtained after seven days of intracanal medicament for the TAP group was (3.63 x 101 [Formula: see text] 5.60) and for the BP group was (3.13 x 101 [Formula: see text] 4.55) with p-value 0.012 < p=0.05, so a significant difference was found between them. This means that when compared with the TAP group, there was a greater amount of reduction in E. faecalis count (CFU/mL) for the BP group seven days after the placement of intracanal medicament, and this reduction was statistically significant. Conclusion This in-vivo study highlights the potential of BP as a more effective intracanal medicament against E. faecalis when compared to the conventional TAP. Bromelain's selectivity for Gram-positive bacteria and its diverse therapeutic properties make it a promising natural alternative for endodontic treatment. Further research is warranted to optimize bromelain's clinical application and assess its potential to enhance endodontic outcomes, potentially revolutionizing the field of endodontics.

Enterococcus faecalis in secondary apical periodontitis: Mechanisms of bacterial survival and disease persistence

Enterococcus faecalis is a commensal bacterium commonly found in the human gastrointestinal tract. However, in individuals with compromised immune systems, the pathogen can lead to severe illness. This opportunistic pathogen is associated with secondary apical diseases and is adept at resisting antibiotics and other forms of treatment because of its numerous virulence factors. Enterococcus faecalis is capable of disrupting the normal functions of immune cells, thereby hindering the body's ability to eradicate the infection. However, intensive research is needed in further understanding the adverse immunomodulatory effects of E. faecalis. Potential strategies specific for eradicating E. faecalis have proven beneficial in the treatment of persistent secondary apical periodontitis.

Identification of potential inhibitors against E.coli via novel approaches based on deep learning and quantum mechanics-based atomistic investigations

Currently, drug resistance to commercially available antibiotics is imparting negative consequences to global health, and the development of novel antibiotics in a timely manner is a prime need of the hour. In the current study, an e-pharmacophore model was built using the 3D structure of DNA gyrase in complex with a standard inhibitor. The generated model was subjected to a pharmacophore based virtual screening against 45,257,086 molecules having 223,460,579 conformers available in MCULE database. Pharmacophore based screening retrieved eight molecules as top hit based on pharmacophoric features in comparison to standard inhibitors. Afterward, all eight compounds were subjected molecular docking based on deep learning algorithm. The molecular docking revealed that compound MCULE-6042843173 and MCULE-2362244223 had significant binding orientation inside active pocket of targeted protein with binding affinity of -9.52 and -9.24 kcal/mol respectively. In addition, density functional theory studies (DFT) were performed to evaluate quantum mechanics of top ranked compounds which were investigated through quantum mechanics (QM) computations which strongly assisted the findings of other in-silico investigations. Consequently, the MCULE-6042843173 and MCULE-2362244223 were subjected to MD simulation studies for evaluation of stability, hydrogen bond analysis, van der Waals interactions, and the contact profile of compounds with targeted amino acid residues. Findings of current study suggested MCULE-6042843173 and MCULE-2362244223 as potential and novel inhibitor of DNA Gyrase enzyme.

Synthesis, Characterization, and Bioactivity of Mesoporous Bioactive Glass Codoped with Zinc and Silver

Due to the overconsumption of antimicrobials, antibiotic-resistant bacteria have become a critical health issue worldwide, especially methicillin-resistant S. aureus (MRSA) and vancomycin-resistant E. faecalis (VRE). Recently, many efforts have been made to load metals into bioactive glasses to enhance the multifunctionality of materials, such as antibacterial and osteoinductive functions. Zinc has been documented to stimulate the gene expression of various regulatory factors in bone cells. Meanwhile, previous studies have reported that silver and zinc could be a promising antibacterial combination with synergistic antimicrobial effects. Here, we sought to develop a biomaterial coreleasing zinc and silver, designated 80S-ZnAg, and to evaluate its antibacterial activity and biocompatibility. The textural analyses demonstrated different coreleasing patterns of zinc and silver for the materials. The chemical characterization revealed that the zinc in 80S-ZnAg could be the network modifier when its molar ratio was high, releasing more zinc; zinc could also be the network former when its molar ratio was low, showing an extremely low rate of release. However, the ICP results for 80S-Zn3Ag2 demonstrated up to 7.5 ppm of zinc and 67.6 ppm of silver. Among all the 80S-ZnAg materials, 80S-Zn3Ag2 demonstrated more marked antibacterial activity against MRSA and VRE than the others, with inhibition zones of 11.5 and 13.4 mm, respectively. The cytotoxicity assay exhibited nearly 90% cell viability at 20 mg/mL of 80-Zn3Ag2. Further clinical study is needed to develop an innovative biomaterial to address the issue of antibiotic resistance.

Antimicrobial and Antibiofilm Activity of Synthetic Peptide [W7]KR12-KAEK Against Enterococcus faecalis Strains

The emergence of infections caused by microorganisms in the oral cavity and increasing concerns regarding the use of antibiotics have resulted in the development of novel antimicrobial molecules, such as antimicrobial synthetic peptides. The purpose of this study was to evaluate the antimicrobial and antibiofilm activities of the native peptide KR-12 and its derivative, the synthetic peptide [W7]KR12-KAEK, against planktonic and biofilms Enterococcus faecalis strains. The methods used to evaluate the antimicrobial activity in planktonic cultures include minimum inhibitory concentration and minimum bactericidal concentration assays. The effects of [W7]KR12-KAEK on biofilm formation and mature biofilms were evaluated by quantifying biomass (crystal violet staining) and counting colony-forming units. Structural assessments of the biofilms and cellular morphological changes were performed using scanning electron microscopy. Peptide [W7]KR12-KAEK showed potential antimicrobial activity against planktonic cells. Interestingly, the native peptide KR-12 showed no antimicrobial activity. Moreover, it inhibited biofilm formation and disrupted the mature biofilms of E. faecalis strains. These results suggest that [W7]KR12-KAEK may be a potential molecule for the development of auxiliary antimicrobial therapies against oral infections.

Evaluation of Antibacterial Efficacy of High-Intensity Focused Ultrasound Versus Photodynamic Therapy Against Enterococcus faecalis-Infected Root Canals

OBJECTIVE

The high incidence of endodontic failure is associated with the remnants of Enterococcus faecalis present within the intricate anatomies of the root canal system (RCS), often inaccessible by the current endodontic practices. This study was aimed at evaluating the effect of high-intensity focused ultrasound (HIFU) and photodynamic therapy (PDT) on E. faecalis biofilms in artificially infected root canals for the potential application in current endodontic practices.

METHODS

Forty-five single-rooted extracted teeth were instrumented using hand files, sterilized in an autoclave, infected with E. faecalis and incubated for 4 wk. The specimens were treated and identified as follows: Control, 4% sodium hypochlorite (NaOCl); riboflavin (1 mg/mL); light only; HIFU (250 kHz, 20 W, 60s); PDT; riboflavin/HIFU; light/HIFU; and riboflavin/HIFU/light. Bactericidal efficacy was determined by colony-forming units (CFU), (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).

RESULTS

Enterococcus faecalis biofilm exhibited significantly lower metabolic activity when treated with HIFU (250 kHz, 20 W, 60 s) compared with the control (4% NaOCl) and PDT groups. A similar phenomenon was observed with the CFU assay. HIFU remained the most effective treatment modality, with consistent results in CLSM and SEM.

CONCLUSION

This study highlighted the potential application of HIFU as an adjunct drug-free, non-destructive root canal disinfection method for endodontic treatment, suggesting an alternative to the current gold standard of 4% NaOCl and PDT.

Comparative Evaluation of Effectiveness of Nisin, Amoxicillin/Clavulanic Acid (Augmentin) and Chlorhexidine on E. Faecalis as an Intracanal Irrigant: An In-vitro Study

Aim

The present study evaluated the antimicrobial efficacy of chlorhexidine gluconate (CHX), Nisin, and Amoxicillin/Clavulanic Acid (Augmentin) as an intracanal irrigant against Enterococcus faecalis (EF).

Materials and Methods

Minimum Inhibitory Concentration (MIC) for EF against Nisin and Augmentin was determined by microbroth dilution technique. Time kill cycle (TKC) analysis was done for 0 MIC, ½ MIC, 1 MIC, and 2 MIC at 0 hour, 15 minutes, 30 minutes, and 45 minutes. At the end of each time period, dilutions were pipetted and swabs of agar plates were done. Incubation of agar plates was done at 37C for 24 hours. Colonies formed were counted.

Results

The time kill curve analysis of EF for CHX, Nisin, and Augmentin at different concentrations and time periods showed a gradual decline in mean bacterial count between 0 and 45 minutes for CHX; this decline increases with increase in concentrations and time. Whereas in group Nisin, not much decline in bacterial count is noted for ½ MIC concentrations but a signification reduction of P < 0.001 after exposure to Nisin at 1 MIC ant 2 MIC concentrations. Group Augmentin showed not much reduction in bacterial count with increase in concentration and time.

Conclusion

From this study, Nisin is found to be a promising agent in eliminating EF in comparison to other irrigants tested. However, the systemic effect of this irrigant, its biocompatibility, allergic potential, and bacterial resistance needs further investigation.

Effect of Enterococcus faecalis Biofilm on Corrosion Kinetics in Titanium Grade 4 Alloys with Different Surface Treatments

E. faecalis has been associated with bacteremia, sepsis, and bacterial endocarditis and peri-implantitis. This microorganism can remain in the alveolus even after extraction of the root remnant. This study aimed to evaluate the corrosion on different surfaces of commercially pure titanium (Ti) grade 4 (Ticp-G4) as a function of the bacterial biofilm effect of Enterococcus faecalis. A total of 57 discs were randomly divided according to their surface finish (n = 19). For microbiological analysis (n = 9), the discs were placed in 12-well plates containing E. faecalis culture and incubated at 37 °C for 7 days. The results show that for the intergroup analysis, considering the "electrolyte" factor, there was a difference between the groups. There was greater biofilm formation for the D.A.Zir group, with greater electrochemical exchange for Biofilm, and the presence of biofilm favored greater electrochemical exchange with the medium.

Combined effect of apigenin and reduced graphene oxide against Enterococcus faecalis biofilms

PURPOSE

Enterococcus faecalis (E. faecalis) is one of the major microorganisms that causes failure of endodontic treatment. This study aimed to investigate the antibacterial activity of apigenin and its synergistic effect with reduced graphene oxide (RGO) in treating E. faecalis biofilms.

METHODS

The antibacterial activities were characterized by viability analysis including colony forming units and confocal laser scanning microscopy (CLSM) analyses. The effect on biofilm biomass was measured using a crystal violet staining method. Live and dead bacteria bio-volumes were determined by CLSM analysis, and the morphology of E. faecalis biofilm after treatment with apigenin and apigenin + RGO was observed by scanning electron microscopy (SEM).

RESULTS

The viability of E. faecalis in biofilms decreased by apigenin treatment in a dose-dependent manner. While apigenin alone did not significantly affect the biofilm biomass, apigenin + RGO reduced the biomass in an apigenin concentration-dependent manner. Likewise, the bio-volume of live bacteria decreased and the bio-volume of dead bacteria increased in apigenin-treated biofilms. According to SEM images, apigenin + RGO-treated samples showed less E. faecalis in biofilms than apigenin-only treated samples.

CONCLUSION

The results suggested that the combined use of apigenin and RGO could be a potential strategy for effective endodontic disinfection.

What is the microbial profile in persistent endodontic infections? A scoping review

INTRODUCTION

This scoping review aimed to map the evidence about the microbiota found in persistent endodontic infections.

METHODS

The study protocol was prospectively registered and is available at https://osf.io/3g2cp. The electronic search was performed in MEDLINE via PubMed, Lilacs, BBO, Scopus, Web of Science, Cochrane Library and EMBASE. The eligibility criteria were based on the PCC acronym, where P (Population): patients with teeth presenting persistent endodontic infection; C (Concept): microbial profile; and C (Context): undergoing endodontic retreatment. Clinical studies that evaluated the microbial profile of samples collected from root canals of teeth undergoing retreatment, using classical or molecular methods, were included. Studies that did not show a minimum period of one year between primary endodontic treatment and retreatment or did not radiographically evaluate the quality of primary root canal filling were excluded. Two reviewers independently selected the articles and collected data.

RESULTS

From a total of 957 articles, 161 were read in full and 32 studies were included. The most prevalent species were Enterococcus faecalis, Parvimonas micra, Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Dialister invisus, Propionibacterium acnes, Tannerella forsythia and Treponema denticola. Cases with symptomatology or inadequate root canal filling presented an increase in specific bacterial species compared to no symptomatology or adequate filling. A greater number of microorganisms was observed in teeth with inadequate coronal restoration compared to adequate restoration.

CONCLUSION

Persistent endodontic infections have a polymicrobial profile identified by the commonly used methods for bacterial detection/identification and are subject to the limitations present in each of those methods.

Comparative Evaluation of Antimicrobial Efficacy of Calcium Hydroxide, Chlorhexidine, and Triple Antibiotic Paste in Different Combination Forms as Intracanal Medicaments against Enterococcus faecalis in Primary Teeth: An In Vivo Randomized Clinical Trial

Aim

To compare and evaluate the antimicrobial efficacy against Enterococcus faecalis (E. faecalis) between a mix of calcium hydroxide [Ca(OH)2] powder and normal saline, a mix of Ca(OH)2 powder and 2% chlorhexidine (CHX) gluconate solution, a mix of triple antibiotic powder (TAP) and normal saline, and mix of TAP and 2% CHX gluconate solution.

Materials and methods

A total of 60 teeth were included in the study. The first sample (S1) was collected after access opening from the widest canal of the tooth by inserting sterile absorbable paper point no 20 up to the full length of the canal for 1 minute. The second sample (S2) was collected after the chemomechanical preparation and irrigation. After that, subjects were randomly divided into four groups-group I-a mix of Ca(OH)2 and normal saline; group II-a mix of Ca(OH)2 and 2% CHX; group III-a mix of TAP and normal saline; and group IV-a mix of TAP and 2% CHX. Assigned intracanal medicaments were placed in the canals, and the teeth were temporarily sealed with a temporary restorative material. On the 7th day, canals were reopened and irrigated, and a third bacteriological sample (S3) was taken out. Later, canals were filled with suitable obturating material, followed by the placement of the permanent restoration.

Results

There was a very highly significant (p < 0.005) difference in E. faecalis count in all the groups on day 7 after placement of intracanal medicament, being highest in group IV followed by group II, group III, and group I.

Conclusion

Triple antibiotic powder (TAP) mixed with 2% CHX gluconate solution has superior antimicrobial efficacy against E. faecalis in primary teeth.

How to cite this article

Qamar S, Jayanna R, Ahuja VR. Comparative Evaluation of Antimicrobial Efficacy of Calcium Hydroxide, Chlorhexidine, and Triple Antibiotic Paste in Different Combination Forms as Intracanal Medicaments against Enterococcus faecalis in Primary Teeth: An In Vivo Randomized Clinical Trial. Int J Clin Pediatr Dent 2023;16(3):448-452.

Effect of Passive Ultrasonic Irrigation, Er,Cr:YSGG Laser, and Photon-Induced Photoacoustic Streaming against Enterococcus faecalis Biofilms in the Apical Third of Root Canals

PURPOSE

This study aimed to compare the antibacterial effectiveness of passive ultrasonic irrigation (PUI), Er,Cr:YSGG laser (WTL), and photon-induced photoacoustic streaming (PIPS) using an Er:YAG laser against Enterococcus faecalis biofilms in the apical third of root canals.

METHODS

Root canals of 70 single-rooted human teeth were instrumented and infected with E. faecalis for 3 weeks to form biofilms. The samples were randomly divided into five groups as follows: (i) PUI + 3% NaOCl (n = 16); (ii) Er,Cr:YSGG laser (n = 16); (iii) PIPS + 3% NaOCl (n = 16); (iv) positive control group (n = 10); and (v) negative control group (n = 10). The bacterial content in the root canal was sampled using (a) the paper-point sampling method before (S1) and after (S2) treatment and (b) pulverising the apical 5 mm of the root. The number of bacteria recovered from each group was counted as colony-forming units (CFUs). The amount of reduction between the groups was compared with the Kruskal-Wallis test and post-test Dunn's multiple comparisons tests. The significance level was set at 5% (p < 0.05).

RESULTS

The samples from the paper-point sampling method showed that the amount of bacteria before (S1) and after treatment (S2) was significantly different between PIPS and WTL, as well as between the PUI and WTL groups. In contrast, no significant difference was found between the PIPS and PUI groups. From the pulverised samples, the results indicated no significant difference among all experimental groups in the amount of bacterial reduction in the apical 5 mm of the root.

CONCLUSIONS

PUI and PIPS showed a significantly greater reduction in bacterial content within the main root canal compared with the WTL. There was no difference among all experimental groups in the apical third of the root.

The presence of Enterococcus faecalis in saliva as a risk factor for endodontic infection

Aim

The aim of the present study was to investigate and correlate the prevalence of Enterococcus faecalis in saliva and in root canals with different pulpal and periapical conditions.

Methodology

Sixty-seven patients were divided into five groups based on pulpal and periapical tissue status: healthy vital teeth (HVT, n=7), healthy treated teeth without lesion (HTT, n=9), irreversible pulpitis (IP, n=13), necrosis (N, n=18), and post-treatment apical periodontitis (PTAP, n=20). Saliva, rubber dam, sterility control and pre-treatment root canal samples were collected and microbiologically processed by culture method. The phylogenetic relationship of E. faecalis isolates collected from root canals and saliva were investigated by whole genome sequencing. Fisher’s exact test was used to correlate the presence of E. faecalis in root canals or saliva with clinical and/or radiographic findings. Linear/logistic regression analyses were performed to establish the relationship between the presence of E. faecalis in root canals, saliva, and the status of periapical tissues.

Results

E. faecalis was found in 18 root canal and saliva samples. E. faecalis root canal isolates were recovered with the highest frequency from post-treatment apical periodontitis. The occurrence of E. faecalis in saliva was strongly associated with its detection in the root canals (P &lt; 0.001). The pretreatment presence of E. faecalis in root canals was associated with significantly higher odds of having periapical lesions (OR=11.03; 95% CI, 1.27-95.70; p &lt; 0.05). Saliva and root canal isolates from the same patient were highly correlated at the phylogenetic level (Jaccard index &gt;0.95).

Conclusion

This pilot study confirms the role of E. faecalis in developing peri-radicular lesions in secondary endodontic infections and suggests that saliva could be the main source of infection. Further studies are needed to investigate the exact origin of this bacteria and its true role in the pathogenesis of secondary/persistent endodontic infections.

One-Pot Preparation of Cetylpyridinium Chloride-Containing Nanoparticles for Biofilm Eradication

Quaternary ammonium compounds (QACs) have been widely used due to their excellent antimicrobial activity. However, using the technology where nanomaterials are employed as drug carriers to deliver QAC drugs has not been fully explored. In this study, mesoporous silica nanoparticles (MSNs) with short rod morphology were synthesized in a one-pot reaction using an antiseptic drug cetylpyridinium chloride (CPC). CPC-MSN were characterized via various methods and tested against three bacterial species (Streptococcus mutans, Actinomyces naeslundii, and Enterococcus faecalis), which are associated with oral infections, caries, and endodontic pathology. The nanoparticle delivery system used in this study prolonged the release of CPC. The manufactured CPC-MSN effectively killed the tested bacteria within the biofilm, and their size allowed them to penetrate into dentinal tubules. This CPC-MSN nanoparticle delivery system demonstrates potential for applications in dental materials.

Isolation and phenotypic characterization of bacteriophage SA14 with lytic- and anti-biofilm activity against multidrug-resistant Enterococcus faecalis

Background

Antimicrobial resistance is a growing global health concern demanding more attention and action at the international-, national- and regional levels. In the present study, bacteriophage was sought as a potential alternative to traditional antibiotics.

Results

Vancomycin-resistant Enterococcus faecalis was isolated from a urine sample. Partial 16S rRNA-gene sequencing and VITEK®2 system were employed for its identification, biochemical characterization, and antibiotic susceptibility testing. The isolate was resistant to eight antibiotics (out of 11): vancomycin, gentamicin (high-level synergy), streptomycin (high-level synergy), ciprofloxacin, levofloxacin, erythromycin, quinupristin/dalfopristin, and tetracycline. Bacteriophage SA14 was isolated from sewage water using the multidrug-resistant isolate as a host. Transmission electron micrographs revealed that phage SA14 is a member of the Siphoviridae family displaying the typical circular head and long non-contractile tail. The phage showed characteristic stability to a wide range of solution pH and temperatures, with optimal stability at pH 7.4 and 4 °C, while showing high specificity toward their host. Based on the one-step growth curve, the phage's latent period was 25 min, and the burst size was 20 PFU/ml. The lytic activity of phage SA14 was evaluated at various multiplicities of infection (MOI), all considerably suppressed the growth of the host organism. Moreover, phage SA14 displayed a characteristic anti-biofilm activity as observed by the reduction in adhered biomass and -viable cells in the pre-formed biofilm by 19.1-fold and 2.5-fold, respectively.

Conclusion

Phage therapy can be a valuable alternative to antibiotics against multi-drug resistant microorganisms.

Taxonomic abundance in primary and secondary root canal infections

AIM

To evaluate the root canal microbiome composition in cases of primary and secondary apical periodontitis.

METHODOLOGY

Thirty-nine samples from patients with primary root canal infections obtained before root canal treatment, and 40 samples obtained during root-end resection procedures from previously filled cases with apical periodontitis were evaluated using 16S rRNA next-generation sequencing analysis (NGS). Demographic and clinical factors included age, sex, infection type, percussion sensitivity, and presence of pain. Differences in abundances of genera were evaluated using Kruskal-Wallis test. Alpha and beta diversity indices were calculated using mothur. The Shannon and Chao1 indices were used to measure alpha diversity. The Bray-Curtis dissimilarity was used to measure beta diversity. Differences in community composition were evaluated using analysis of similarity (ANOSIM) with Bonferroni correction for multiple comparisons.

RESULTS

Significantly fewer operational taxonomic units values were observed from samples from secondary infections (p < .0001). While no significant differences were observed in the Chao 1 index between primary and secondary infections, the Shannon alpha diversity was significantly lower in secondary relative to primary infections (p = .008). Among samples, sex, age (adult vs. older adult), percussion sensitivity, and presence of pain all showed no significant effects on community composition via an analysis of similarity (ANOSIM). However, community composition was significantly different depending on whether the sample was from a primary or secondary infection (R = .051, p = .03). Nine microbial genera comprised the predominant taxa observed among samples (>3.3%) and included Parvimonas, Fusobacterium, Campylobacter, Arachnia, Eubacterium, Prevotella, Peptostreptococcus, Fretibacterirum, and Pseudoramibacter. Significantly greater relative abundances of Prevotella, Peptostreptococcus, Veillonella, Lactucaseibacillus, and Dialister were observed in primary infections.

CONCLUSIONS

Primary endodontic infections are more diverse than secondary infections. The microbial composition is not associated with the clinical manifestations of apical periodontitis.

Ex vivo Detection of Amyloid-β in Naturally Formed Oral Biofilm

Background

Oral infection has been implicated in the possible etiology of Alzheimer's disease.

Objective

To detect amyloid-β (Aβ) within microbial biofilms.

Methods

Freshly extracted teeth (N = 87) with periodontal disease were separated into Group A (N = 11), with primary root canal infection and Group B (N = 21) with failed endodontic treatment identified by the presence of, gutta percha root filling. Biofilm characteristics were observed by scanning electron microscopy (SEM). Demineralized paraffin wax embedded tooth sections and mineralized calculus biofilm were immunostained with the anti-Aβ antibody. The gutta perchas were processed either for on-section acrylic resin tissue immunocolloidal gold silver staining (IGSS) using the anti-Aβ antibody or in Araldite resin for ultrastructure.

Results

SEM demonstrated calculus and gutta percha in situ harboring a polymicrobial biofilm featuring extracellular polymeric substance (EPS) and water channels. Immunohistochemistry on rehydrated paraffin wax tooth sections from Group A, demonstrated Aβ staining on external (calculus and plaque) and all intracanal infected regions. In Group B, the gutta percha biofilm IGSS gave an inconclusive result for Aβ. Transmission electron microscopy of selected teeth with infected intra-canals (Group A) and 20% of gutta percha biofilm (Group B) EPS contained electron dense fibrils of variable sizes, some of which were typical of human Aβ fibrils.

Conclusion

This study detected both soluble and insoluble Aβ fibrils within the EPS of periodontal and endodontic natural biofilm, strongly suggesting its role as an antimicrobial peptide in combatting local infection, with potential risk for cross-seeding into the brain for AD development.

Transcriptome Analysis Reveals Modulation of Human Stem Cells from the Apical Papilla by Species Associated with Dental Root Canal Infection

Interaction of oral bacteria with stem cells from the apical papilla (SCAP) can negatively affect the success of regenerative endodontic treatment (RET). Through RNA-seq transcriptomic analysis, we studied the effect of the oral bacteria Fusobacterium nucleatum and Enterococcus faecalis, as well as their supernatants enriched by bacterial metabolites, on the osteo- and dentinogenic potential of SCAPs in vitro. We performed bulk RNA-seq, on the basis of which differential expression analysis (DEG) and gene ontology enrichment analysis (GO) were performed. DEG analysis showed that E. faecalis supernatant had the greatest effect on SCAPs, whereas F. nucleatum supernatant had the least effect (Tanimoto coefficient = 0.05). GO term enrichment analysis indicated that F. nucleatum upregulates the immune and inflammatory response of SCAPs, and E. faecalis suppresses cell proliferation and cell division processes. SCAP transcriptome profiles showed that under the influence of E. faecalis the upregulation of VEGFA, Runx2, and TBX3 genes occurred, which may negatively affect the SCAP's osteo- and odontogenic differentiation. F. nucleatum downregulates the expression of WDR5 and TBX2 and upregulates the expression of TBX3 and NFIL3 in SCAPs, the upregulation of which may be detrimental for SCAPs' differentiation potential. In conclusion, the present study shows that in vitro, F. nucleatum, E. faecalis, and their metabolites are capable of up- or downregulating the expression of genes that are necessary for dentinogenic and osteogenic processes to varying degrees, which eventually may result in unsuccessful RET outcomes. Transposition to the clinical context merits some reservations, which should be approached with caution.

Evaluation of the Antibacterial Effect of Xylene, Chloroform, Eucalyptol, and Orange Oil on Enterococcus faecalis in Nonsurgical Root Canal Retreatment: An Ex Vivo Study

Objectives

The present ex vivo study is aimed at evaluating the antibacterial efficacy of chloroform, eucalyptol, orange oil, and xylene against E. faecalis biofilm during nonsurgical root canal retreatment.

Materials and Methods

Eighty single-rooted teeth were instrumented. The samples were autoclaved, infected with E. faecalis for 4 weeks, and obturated with gutta-percha. Then the teeth were randomly assigned to 4 groups (n = 20): (1) chloroform, (2) eucalyptol, (3) orange oil, and (4) xylene. In all of the groups, gutta-percha removal was conducted according to the same protocol although the solvent used in each group was different. Bacterial samples were collected after gutta-percha removal and following additional apical enlargement. Intergroup and intragroup analyses were conducted using one-way ANOVA combined with the post hoc Tukey test and the paired-sample t-test, respectively. Statistical significance was set to 0.05.

Results

All of the groups showed more than 99% bacterial load reduction. The least bacterial load after gutta-percha removal was observed in the chloroform group (p < 0.001). The orange oil group showed a significantly lower bacterial load compared to the eucalyptol group (p = 0.001), while it was not different from the xylene group (p = 0.953). The xylene group also had a significantly lower bacterial load compared with the eucalyptol group (p = 0.017). After apical enlargement, the chloroform group had a significantly lower bacterial load compared to the other groups. The comparison of bacterial load values before and after apical enlargement in the chloroform and eucalyptol groups showed a statistically significant difference (p_choloroform = 0.011, p_eucalyptol = 0.001).

Conclusion

Chloroform was the most effective solvent in terms of antimicrobial activity against E. faecalis followed by orange oil and xylene, which were not significantly different though, and eucalyptol. All of the solvents showed more than 99% bacterial load reduction. Chloroform and xylene revealed to be associated with favorable antibiofilm activity among the examined solvents.

Cytocompatibility and antimicrobial activity of a novel endodontic irrigant combining citric acid and chlorhexidine

OBJECTIVES

This study aimed to evaluate the antibacterial ability and cytocompatibility of a new irrigant solution for endodontic treatment composed of 10% citric acid (CA) and 1% chlorhexidine (CHX).

METHODS

Thirty-five extracted single-canal human teeth were selected and de-crowned. Canal systems (n = 7/group) were infected with Enterococcus faecalis for 4 weeks and subject to irrigation with 1% CHX; 10% CA; irrigating solution 10% CA associated with 1% CHX (CACHX); 2.5% NaOCl or sterile water (control). Microbiological samples were collected immediately and 18 h after irrigation (enriched samples). The canals were filled with culture medium post irrigation to verify the bacterial presence/absence qualitatively and quantitatively through colony counting (log₁₀ CFU/mL). A multiparametric assay was performed after exposure of human periodontal ligament fibroblasts (HPdLF) to the test solutions. The Kruskal-Wallis test with Dunn´s post-test and Fisher's exact test were employed at the 95% confidence level to compare differences among groups.

RESULTS

All tested solutions were cytocompatible with human periodontal ligament fibroblasts. No difference was observed on antibacterial activity between 1% CHX, 10% CA, CACHX and 2.5% NaOCl (p > 0.05). Eighteen hours after irrigation, CACHX samples were the only that did not present E. faecalis in the root canal system.

CONCLUSIONS

The demonstrated good in vitro biocompatibility and elimination of E. faecalis suggest a potential use of 10% CA associated with 1% CHX as a solution for microbiological control during endodontic treatment.

CLINICAL RELEVANCE

Irrigants play an essential role during endodontic therapy. This irrigating solution, based on the association of 10% citric acid with 1% chlorhexidine, seems viable for clinical procedures.

In Vitro Evaluation of Five Newly Isolated Bacteriophages against E. faecalis Biofilm for Their Potential Use against Post-Treatment Apical Periodontitis

State-of-the-art treatment of root canal infection includes the use of mechanical debridement and chemical agents. This disinfection method is limited, and microorganisms can remain in the canal system. Enterococcus faecalis appears with a high prevalence in secondary and persistent root canal infections and can be linked to endodontic treatment failure due to its various resistance mechanisms. Here, we evaluated the activity of newly isolated bacteriophages against clinical isolates of E. faecalis (including one vancomycin- and gentamicin-resistant strain) as a single treatment or in combination with gentamicin and vancomycin. For the resistant strain, daptomycin and fosfomycin were tested. Sixteen E. faecalis strains were used to screen for the presence of bacteriophages in sewage. Five different bacteriophages were characterized in terms of virion morphology, host range and killing-kinetics against each E. faecalis host strain. To investigate the antibiofilm effect of antibiotic and phages, E. faecalis biofilm was grown on porous glass beads and treated with different antibiotic concentrations and with isolated bacteriophages alone or in staggered combinations. A strong biofilm reduction was observed when phages were combined with antibiotic, where combinations with gentamicin showed a better outcome compared to vancomycin. Regarding the resistant strain, daptomycin had a superior antibiofilm effect than fosfomycin.

Efficacy of chitosan paste as intracanal medication against Enterococcus faecalis and Candida albicans biofilm compared with calcium hydroxide in an in vitro root canal infection model

Background

Enterococcus faecalis and Candida albicans are frequently found in persistent endodontic infection and could remain in dentinal tubules despite intracanal medication with calcium hydroxide (Ca(OH)₂), a commonly used medication. Thus, an effective and safe antimicrobial medication against such refractory infection is necessary in endodontic retreatment, so we aimed to test the efficacy of chitosan paste against these microorganisms compared with Ca(OH)₂ in root canals of extracted human teeth.

Methods

Thirty-six sterilized human root samples prepared from extracted premolars and upper maxillary incisors were infected with E. faecalis for 14 days, while 32 were infected with C. albicans for 48 h, for mature biofilm formation. The samples were assigned to 6 groups of intracanal medications: Group 1: no medication (negative control); Group 2: 20% Polyethylene glycol (PEG); Group 3: 20% Propylene glycol (PG); Group 4: Ca(OH)₂; Group 5: Chitosan + PEG; and Group 6: Chitosan + PG. After 7 days, intracanal surface dentin was harvested using Protaper next, resuspended, serially diluted and spread on Brain–Heart-Infusion agar (for E. faecalis) and Yeast Extract-Peptone-Dextrose agar (for C. albicans) for colony count. Antimicrobial efficacy was determined as percentage of remaining colony forming unit (CFUs) relative to negative control and analyzed using One-way ANOVA and post-hoc Games-Howell test. The significance level was set at 0.05.

Results

For E. faecalis, chitosan + PG had significantly higher antibacterial activity than Ca(OH)₂ (P = 0.039). Chitosan + PEG and chitosan + PG medication significantly reduced viable bacteria compared with negative control, PEG and PG (P = 0.001, 0.003, 0.024, respectively for chitosan + PEG; P = 0.002, 0.003, 0.014, respectively for chitosan + PG). For C.albicans, chitosan + PEG and chitosan + PG were not significantly different from Ca(OH)₂. However, Chitosan + PEG and chitosan + PG, but not Ca(OH)₂, showed a significantly lower level of remaining CFUs compared with negative control (P = 0.013 and 0.005, respectively).

Conclusion

Chitosan paste showed better efficacy in reducing viable E. faecalis biofilm when compared to Ca(OH)₂ after 7-day intracanal medication in this in vitro root canal model. It could also significantly reduce viable C. albicans, but was not significantly different from Ca(OH)₂.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02385-x.

Antibacterial Activity of Electrospun Polyacrylonitrile Copper Nanoparticle Nanofibers on Antibiotic Resistant Pathogens and Methicillin Resistant Staphylococcus aureus (MRSA)

Bacteria induced diseases such as community-acquired pneumonia (CAP) are easily transmitted through respiratory droplets expelled from a person’s nose or mouth. It has become increasingly important for researchers to discover materials that can be implemented in in vitro surface contact settings which disrupt bacterial growth and transmission. Copper (Cu) is known to have antibacterial properties and have been used in medical applications. This study investigates the antibacterial properties of polyacrylonitrile (PAN) based nanofibers coated with different concentrations of copper nanoparticles (CuNPs). Different concentrations of copper sulfate (CuSO₄) and polyacrylonitrile (PAN) were mixed with dimethylformamide (DMF) solution, an electrospinning solvent that also acts as a reducing agent for CuSO₄, which forms CuNPs and Cu ions. The resulting colloidal solutions were electrospun into nanofibers, which were then characterized using various analysis techniques. Methicillin-Resistant isolates of Staphylococcus aureus, an infective strain that induces pneumonia, were incubated with cutouts of various nanocomposites using disk diffusion methods on Luria-Bertani (LB) agar to test for the polymers’ antibacterial properties. Herein, we disclose that PAN-CuNP nanofibers have successfully demonstrated antibacterial activity against bacteria that were otherwise resistant to highly effective antibiotics. Our findings reveal that PAN-CuNP nanofibers have the potential to be used on contact surfaces that are at risk of contracting bacterial infections, such as masks, in vivo implants, or surgical intubation.

Enhancing the intracanal antibacterial effects of sodium hypochlorite with etidronic acid or citric acid

INTRODUCTION

This study evaluated the bacterial reduction promoted by root canal preparation using irrigation with sodium hypochlorite (NaOCl) alone, associated with etidronic acid (HEDP) or alternated with citric acid, and after a supplementary agitation step.

METHODS

Extracted mandibular premolars were selected and distributed into 3 groups based on anatomically paired micro-computed tomographic analyses. The canals were contaminated with Enterococcus faecalis for 30 days and then subjected to chemomechanical preparation with a reciprocating instrument under irrigation with NaOCl alone, mixed with HEDP (NaOCl/HEDP), or alternated with citric acid (NaOCl/CA). A supplementary agitation step with the XP-endo Finisher was performed in all groups. Intracanal bacteriological samples were taken before (S1) and after preparation (S2), and after the supplementary approach (S3). DNA was extracted from the samples and subjected to quantitative real-time polymerase chain reaction.

RESULTS

Intragroup analyses revealed a substantial bacterial reduction from S1 to S2 or S3 in all groups (p<0.01). The supplementary agitation resulted in S2-to-S3 bacterial reduction of 6%, 68%, and 80% in the NaOCl, NaOCl/HEDP, and NaOCl/CA groups, respectively. Irrigation with NaOCl alone resulted in 53% and 47% of samples negative for bacteria in S2 and S3, respectively. Corresponding figures for NaOCl/HEDP were 75% and 85%, and 44% and 72% for NaOCl/CA. Intergroup analyses of S2 samples showed that NaOCl/HEDP was significantly more effective than the other two in reducing the bacterial levels (p<0.05). After the supplementary approach, both NaOCl/HEDP and NaOCl/CA were significantly more effective than NaOCl alone (p<0.05), with no significant differences between them (p>0.05).

CONCLUSION

Both the freshly combined NaOCl/HEDP solution and the alternate use of NaOCl and citric acid followed by XP-endo Finisher agitation resulted in significantly higher intracanal bacterial reduction than NaOCl alone.

No-ozone cold plasma can kill oral pathogenic microbes in H2O2-dependent and independent manner

To apply the sterilisation effect of low-temperature plasma to the oral cavity, the issue of ozone from plasma must be addressed. In this study, a new technology for generating cold plasma with almost no ozone is developed and is named Nozone (no-ozone) Cold Plasma (NCP) technology. The antimicrobial efficacy of the NCP against four oral pathogens is tested, and its specific mechanism is elucidated. The treatment of NCP on oral pathogenic microbes on a solid medium generated a growth inhibition zone. When NCP is applied to oral pathogens in a liquid medium, the growth of microbes decreased by more than 10⁵ colony forming units, and the bactericidal effect of NCP remained after the installation of dental tips. The bactericidal effect of NCP in the liquid medium is due to the increase in hydrogen peroxide levels in the medium. However, the bactericidal effect of NCP in the solid medium depends on the charged elements of the NCP. Furthermore, the surface bactericidal efficiency of the dental-tip-installed NCP is proportional to the pore size of the tips and inversely proportional to the length of the tips. Overall, we expect this NCP device to be widely used in dentistry in the near future.

Antibacterial efficacy of peracetic acid in comparison with sodium hypochlorite or chlorhexidine against Enterococcus faecalis and Parvimonas micra

Background

The main goal of an endodontic treatment is a complete debridement of the root canal system; however, currently mechanical shaping and chemical cleaning procedures for this purpose have deemed non-satisfactory.

Methods

The efficacy of peracetic acid (PAA; 0.5, 1.0, 2.0%), as a root canal irrigation solution, against Enterococcus faecalis (DSM 20478) and Parvimonas micra (DSM 20468) when compared with the one of sodium hypochlorite (NaOCI; 1.0, 3.0, 5.0%), chlorhexidine digluconate (CHX; 0.12, 0.2, 2.0%) and 0.9% NaCI (as a control solution) was in vitro investigated with the agar diffusion and direct contact methods. The inhibition zone diameters observed with the agar diffusion test were determined. The viable bacterial counts (CFU/ml) were calculated with the direct method.

Results

The agar diffusion test showed that all three root canal irrigation solutions had an efficacy against E. faecalis at all concentrations. The largest inhibition zone diameters against E. faecalis were observed with 5.0% NaOCI. At all three concentrations of PAA, NaOCI, and CHX, the inhibition zone diameter increased with increase in concentration. For P. micra, PAA had a similar inhibition zone diameter despite a concentration increase. In contrast, for NaOCI and CHX, the inhibition zone diameter increased with increasing concentration. 2.0% CHX produced the largest inhibition zone diameter against P. micra. For E. faecalis, only the comparison between 2.0% PAA and 5.0% NaOCI showed statistical significance (p = 0.004). For P. micra the efficacy comparison between the lowest, middle, and highest concentrations of each solution, a statistical significance (p < 0.05) was found for all three solutions. After direct contact with PAA, NaOCI and CHX, no viable bacteria could be determined for either P. micra or E. faecalis.

Conclusions

PAA had a similar antibacterial efficacy as the one of NaOCl and CHX when in direct contact with E. faecalis and P. micra. In the agar diffusion test, PAA showed a similar antibacterial efficacy as the one of CHX and a lower one as the one of NaOCl for E. faecalis.

Quantification of Bacterial DNA from Infected Human Root Canals Using qPCR and DAPI after Disinfection with Established and Novel Irrigation Protocols

The removal of bacterial infections within the root canal system is still a challenge. Therefore, the cleansing effect of established and new irrigation-protocols (IP) containing silver diamine fluoride (SDF) 3.8% on the whole root canal system was analyzed using quantitative PCR (qPCR) and 4′,6-diamidino-phenylindole-(DAPI)-staining. Extracted human premolars were instrumented up to F2 (ProTaper Gold) under NaCl 0.9% irrigation and incubated with Enterococcus faecalis for 42 days. Subsequently, different ultrasonically agitated IP were applied to the roots: control (no irrigation), 1. NaOCl 3%, EDTA 20%, CHX 2%, 2. NaOCl 3%, EDTA 20%, 3. NaOCl 3%, EDTA 20%, SDF 3.8%, 4. SDF 3.8%, and 5. NaCl 0.9%. One half of the root was investigated fluorescent-microscopically with DAPI. The other half was grinded in a cryogenic mill and the bacterial DNA was quantified with qPCR. The qPCR results showed a statistically significant reduction of bacteria after the application of IP 1, 2, and 3 compared to the control group. While IP 4 lead to a bacterial reduction which was not significant, IP 5 showed no reduction. These data corresponded with DAPI staining. With qPCR a new molecular-biological method for the investigation of the complete root canal system was implemented. The novel IP 3 had an equally good cleansing effect as the already established IP.

Evaluation of the effectiveness of GentleWave System and passive ultrasonic irrigation with minimally invasive and conventional instrumentation technique against Enterococcus faecalis lipoteichoic acid (LTA) in infected root canals

INTRODUCTION

This study evaluated the effectiveness GentleWave System (GWS) and passive ultrasonic irrigation (PUI) in removing E. faecalis lipoteichoic acid (LTA) from infected root canals with minimally invasive (MIT) and conventional instrumentation techniques (CIT).

METHODS

Sixty extracted human maxillary first premolars were included. All teeth were dentin pretreated and inoculated with LTA prepared from Enterococcus faecalis. First, twelve teeth were cryogenically ground to investigate the viability of recovering intraradicular E. faecalis LTA. After, forty-eight teeth were randomly divided into groups: GWS + MIT, GWS + CIT, PUI + MIT, and GWS + CIT (all =12). Teeth were instrumented with Vortex Blue rotary file size 15/.04 for MIT and 35/.04 for CIT. Samples were collected before (s1) and after a root canal procedure (s2) with sterile/ apyrogenic paper points and after cryogenically ground for intraradicular LTA analysis (s3). LTA was quantified with the LTA ELISA kit.

RESULTS

E. faecalis LTA was recovered from 100% of the samples (48/48) at s1. GWS + MIT and GWS + CIT were the most effective protocols against E. faecalis LTA, with no difference between them (p>.05). PUI + CIT was more effective than PUI + MIT (p<.05) but less effective than GWS + MIT and GWS + CIT (p<.05). GWS groups showed more root canals with undetected E. faecalis LTA after treatment than all groups tested.

CONCLUSIONS

GWS + MIT and GWS + CIT were the most effective protocol against E. faecalis LTA in infected root canals.

Biocompatibility and Antibacterial Action of Salvadora persica Extract as Intracanal Medication (In Vitro and Ex Vivo Experiment)

This study aimed to test the biocompatibility and antibacterial properties of Salvadora persica (S. persica) extract, a natural product, as an intracanal medication in comparison with calcium hydroxide (Metapaste, META BIOMED, Cheongju, Korea). The pH values of both materials were tested. The biocompatibility of S. persica extract and Metapaste was determined using light microscopy and MTT assays. The antibacterial action was tested using the zone of bacterial inhibition on four common bacterial species. In addition, intracanal medication was administered using 68 extracted single-rooted teeth contaminated with Enterococcus faecalis (E. faecalis), and the percentage reduction in colony count (% RCC) at 1, 3, and 7 days was measured. The extension of activity for both materials was assessed using histological sections and scanning electron microscopy. S. persica was found to be acidic in nature. Both materials showed significantly lower cell viability than the positive control cells on days 1 and 3 but not on day 7. S. persica showed better antibacterial effects against E. faecalis and S. mutans. S. persica extract showed 97.6%, 98.9%, and 99.3% RCC values at 1, 3, and 7 days, respectively, which are comparable to those of Metapaste. S. persica herbal extract is a promising material that can be utilized as an intracanal medication, but its use requires further research.

MATLAB Simulation-Based Theoretical Study for Detection of a Wide Range of Pathogens Using 1D Defective Photonic Structure

The present 1D photonic biosensor is composed of two sub-PhCs of alternate layers made of GaP and SiO2. The period number of each PhC has been fixed to 3. Both these PhCs are joined together through a cavity region of air in which different analytes are to be filled one by one under the scope of this study. The theoretical findings of this work have been formulated with the help of the well-known transfer matrix method. Moreover, all the computations pertaining to this work have been carried out with the help of MATLAB software. The effect of change in cavity thickness and angle of incidence corresponding to a TE wave on the transmittance of the structure (AB)ND(AB)N has been studied theoretically which in turn determines the performance of the proposed biosensor. Various parameters, such as sensitivity (S), signal to noise ratio (SNR), figure of merit (FOM), resolution (RS), detection limit (LOD), quality factor (Q) and dynamic range (DR) have been theoretically calculated to evaluate the performance of the proposed design in true sense. The sensitivity of this structure varies between the highest and lowest values of 337.3626 nm/RIU and 333.0882 nm/RIU corresponding to water samples containing Pseudomonas aeruginosa cells and Bacillus anthracia cells, respectively, under normal incidence condition with a cavity thickness of 2.0 µm. The resolution (in nm) and LOD (in RIU) values of the proposed design are small enough and are significant for our structure. This study may also be helpful for distinguishing various microbiological samples under investigation and find suitable applications for discriminating bacterial cells from spores.

Synergistic In Vitro Antimicrobial Activity of Triton X-100 and Metformin against Enterococcus faecalis in Normal and High-Glucose Conditions

The prevention and treatment of oral diseases is more difficult in diabetic patients with poorly controlled blood glucose levels. This study aims to explore an effective, low-cytotoxicity medication for root canal treatment in diabetic patients. The antibacterial effect of the combination of Triton X-100 (TX-100) and metformin (Met) on Enterococcus faecalis (E. faecalis) was evaluated by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration required to kill 99% bacteria (MBC₉₉) and by conducting dynamic time-killing assays. While the antibiofilm activity was measured by crystal violet (CV) assay, field emission scanning electron microscope (FE-SEM), confocal laser scanning microscope (CLSM) and colony-forming unit (CFU) counting assays. The expression of relative genes was evaluated by real-time quantitative polymerase chain reaction (RT-qPCR), and the cytotoxicity of the new combination on MC3T3-E1 cell was also tested. Results showed that the antibacterial and antibiofilm activities of Met could be significantly enhanced by very low concentrations of TX-100 in both normal and high-glucose conditions, with a much lower cytotoxicity than 2% chlorhexidine (CHX). Thus, the TX-100 + Met combination may be developed as a promising and effective root canal disinfectant for patients with diabetes.

GC/MS Profiling and Ex Vivo Antibacterial Activity of Salvadora persica (Siwak) against Enterococcus faecalis as Intracanal Medicament

INTRODUCTION

Salvadora persica L. (S. persica, Siwak) has been used for many centuries as oral hygiene tools, particularly in Saudi Arabia. This study aimed to assess the effectiveness of S. persica petroleum ether extract (SPE) as an intracanal bactericidal for endodontic treatment against Enterococcus faecalis. Calcium hydroxide Ca(OH)₂ gold standard intracanal medicament was used for comparison.

METHODS

The gas chromatography mass spectrometry (GC/MS) analysis was carried out to identify the components of SPE. First, the consistency of SPE was accomplished according to ANSI/ADA specification no 57. Forty-five single-rooted mandibular premolars were infected with that of E. faecalis suspension. Colony-forming units (CFU) were counted before the medicaments' application (CFU-1) and after seven days of their applications (CFU-2). Group I: SPE, Group II: positive control Ca(OH)₂, and Group III: saline solution negative control. The microdilution method was applied to determine minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of SPE.

RESULTS

Thirty-two compounds were identified (89.09%), with main components of benzyl isothiocyanate (BITC) (33.32%) and steroids (34%). CFU before and after using SPE and Ca(OH)₂ recorded a statistically significant reduction in bacterial count (P=0.006) and (P=0.01), respectively. There was an insignificant difference between CFU after using SPE and Ca(OH)₂ (P=0.210). On the contrary, comparing both medicaments with the negative control saline group resulted in significant differences, (P=0.001) and (P=0.007), respectively. Moreover, the equality of minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) of SPE is recorded.

CONCLUSION

This finding could be referred to the high content of bactericidal BITC in synergism with other antimicrobial components, representing 70.71% of SPE. Thus, SPE is a good candidate as an intracanal medicament, which warrants further investigation.

Comparative evaluation of antimicrobial efficacy of calcium hydroxide, triple antibiotic paste and bromelain against Enterococcus Faecalis: An In Vitro study

Context:

Considering the effectiveness and safety concerns of synthetic intracanal medicaments (ICM), alternative usage of herbal ingredients in the root canal treatment may prove to be beneficial. Hence, the naturally available potent proteolytic, anti-inflammatory, and antimicrobial pineapple extract Bromelain as an ICMs needs to be studied.

Aim:

The aim of this study is to evaluate and compare the antimicrobial efficacy of calcium hydroxide (CaOH) and triple antibiotic paste (TAP) with Bromelain against Enterococcus faecalis bacteria using the turbidity method.

Materials and Methods:

Forty-four freshly extracted single-rooted teeth were collected and 6 mm sections were prepared. These samples were infected with E. faecalis bacteria (ATCC 29212), randomly divided into four groups. Negative control, CaOH paste, TAP, and Bromelain paste. After the removal of medicament, the optical density (OD) of the dentinal shavings was measured using a spectrophotometer.

Statistical Analysis:

The Chi-square and Kruskal − Wallis ANOVA test were used. The confidence interval was set to 95% at 5% significance level.

Results:

TAP showed less OD than CaOH₂ paste which is statistically significant. (P = 0.0022). The OD reading of Bromelain paste was less than CaOH₂ with P = 0.007. The OD of Bromelain and TAP were statistically insignificant (P = 0.095), indicating their comparable antibacterial efficacy.

Conclusions:

The antimicrobial efficiency of Bromelain was found to be more effective than Ca (OH) ₂ paste and comparable to TAP against E. faecalis.