Evaluation of the presence of Enterococcus Faecalis in root cementum: A confocal laser scanning microscope analysis

Comparative evaluation of antimicrobial efficacy of chitosan nanoparticles and calcium hydroxide against endodontic biofilm of Enterococcus faecalis: An in vitro study

Aim

The aim of the study was to assess and evaluate the antimicrobial effectiveness of chitosan nanoparticles (CSNPs) with calcium hydroxide in the elimination of Enterococcus faecalis.

Materials and Methods

Using the broth microdilution method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of calcium hydroxide and CSNPs were measured. The antibiofilm effect of calcium hydroxide and CSNPs against E. faecalis biofilm was qualitatively analyzed using a crystal violet assay. A 7-day-old biofilms of E. faecalis grown on dentine discs were assigned to the following three groups (n = 11 dentine discs), normal saline (group I), calcium hydroxide (group II), and CSNPs (group III). Quantification of live and dead cells using confocal microscopy was done to evaluate the antibiofilm efficacy of the medicaments included in the study.

Results

MIC of calcium hydroxide and CSNPs against E. faecalis was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. MBC of calcium hydroxide and CSNPs was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. Using Crystal Violet (CV) assay, calcium hydroxide and CSNPs showed biofilm inhibition at concentrations of 2.5 mg/mL and 0.625 mg/mL, respectively. Confocal laser scanning microscopy analysis found that both calcium hydroxide and CSNPs showed a significant decrease in viable cells at their MBC values compared to the control group's normal saline. CSNPs showed a significantly lower percentage of live cells than calcium hydroxide (P < 0.05).

Conclusion

The study results reveal that the antimicrobial efficacy of CSNPs is better than calcium hydroxide and normal saline against E. faecalis biofilm.

Antibiofilm efficacy of biosynthesized silver nanoparticles against endodontic-periodontal pathogens: An in vitro study

Background:

Endodontic-periodontal pathogens exist as biofilms which are difficult to eliminate. Biosynthesized silver nanoparticles (AgNPs) emerged as newer antimicrobial agents with potential benefits.

Aim:

The aim of this study is to determine the minimum inhibitory concentration (MIC); evaluate the antibiofilm efficacy of fungal-derived AgNPs against Porphyromonas gingivalis, Bacillus pumilus, and Enterococcus faecalis.

Materials and Methods:

MIC of AgNPs against test pathogens was determined using micro broth dilution method. Serial dilutions of AgNPs ranging from 80 to 1 μg/ml concentration were added to wells containing 10 μl of bacterial inoculum in culture media and control group without AgNPs. For biofilm models, 120 dentin blocks were prepared, sterilized, and contaminated for 2 weeks with (n = 40 each). Group 1: B. pumilus, Group 2: E. faecalis, and Group 3: P. gingivalis and each group is divided into four subgroups (n = 10 each) and treated with distilled water, AgNPs, 2% and 0.2% chlorhexidine (CHX). Colonies counted after 24 h of incubation and statistically analyzed using one-way ANOVA and post hoc Tukey tests.

Results:

MIC for B. pumilus was determined as 20 μg/ml and 30 μg/ml for E. faecalis and P. gingivalis. AgNPs were effective as 2% CHX against all biofilms compared to control group. Post hoc Tukey test (P < 0.0001) shows no significant difference between groups.

Conclusion:

Fungal-derived AgNPs are effective against endo-perio pathogens.

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.

Biosynthesis, Characterization and Antibacterial Efficacy of Silver Nanoparticles Derived from Endophytic Fungi against P. gingivalis

Introduction

Microbial resistance to existing antimicrobial agents in periodontal therapy is a growing problem. Therefore, there is a need for development of new antimicrobial agents.

Aim

To biosynthesize and characterize Silver Nanoparticles (AgNPs) using endophytic fungi and to evaluate the antibacterial efficacy against P. gingivalis.

Materials and Methods

Cut leaf segments of Withania Somnifera (Ashwagandha) were used to isolate the fungi. Fresh cultures of fungi were inoculated in Erlenmeyer flask of 100 ml Malt Glucose Yeast Peptone (MGYP) broth and incubated at 29°C for 72 hours for the biomass to grow. Biomass was filtered and cell free fungal filtrate was used further. Biosynthesized AgNPs were characterized by visual observation, Ultraviolet-Visible (UV-Vis) spectrophotometer, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction Analysis (SAED) and Fourier Transform Infrared Spectroscopy (FTIR). Antibacterial efficacy was evaluated by agar diffusion method measuring the zone of inhibition. The study groups included different concentrations of AgNPs: A (20 μl), B (40 μl), C (60 μl), D (80 μl) and E (100 μl) of AgNPs, F (0.2% CHX), G (2% CHX), H (Ampicillin) and I (sterile distilled water). The data collected for inhibition zones were statistically analysed using One-way Anova followed by Tukey post-hoc multiple comparison tests.

Results

The fungi were identified as Fusarium semitectum. Characterization studies showed the colour change from colourless to reddish brown; U-V spectrum showed peak 420 nm, TEM revealed the particles spherical in shape and 10-20 nm in size. FTIR analysis revealed the presence of functional groups. AgNPs 80 μl and 100 μl showed mean zone of inhibition 17.33 and 18 mm against P. gingivalis. CHX (0.2%) 17.85 and CHX (2%) 19.97 mm, Ampicillin 20.5 mm and no zone for sterile distilled water.

Conclusion

Biosynthesized AgNPs showed efficient antibacterial efficacy against P. gingivalis hence, creates a new horizon in periodontal therapy.

Bactericidal Efficacy of Photodynamic Therapy and Chitosan in Root Canals Experimentally Infected with Enterococcus faecalis: An In Vitro Study

OBJECTIVE

To evaluate the antibacterial efficacy of photodynamic therapy (PDT) and chitosan against Enterococcus faecalis and assess the possible enhancive effect of chitosan on the photosensitizer methylene blue in experimentally infected root canals of extracted human teeth in vitro.

BACKGROUND DATA

E. faecalis is frequently found in persistent endodontic infections. In this context, the antimicrobial PDT or newer antibacterial alternatives such as chitosan could become modern alternatives to existing antibacterial treatment approaches.

METHODS

One hundred two single-rooted extracted teeth were used. The teeth were contaminated with 0.1 mL E. faecalis (3 × 10⁸ cell/mL). These were randomized into six treatment groups (n = 17 teeth): Group 1 (2.5% NaOCl); Group 2 (PDT); Group 3 (chitosan 3 mg/mL); Group 4 (PDT+chitosan 3 mg/mL); Group 5 (positive control, no treatment); and Group 6 (negative control, no inoculation, no treatment). The canal content was sampled with sterile paper points. The samples were cultured on blood agar plates to determine the number of colony-forming units (CFU)/mL. Five teeth in each group were analyzed by scanning electron microscope (SEM) to determine the percentage of area with contamination and debris.

RESULTS

The positive control group showed the highest number of CFU/mL, with statistically significant differences in comparison with the other treatment groups (p ≤ 0.05). Group 4 (PDT+chitosan) showed the lowest CFU/mL count, followed by Group 2 (PDT alone), which obtained similar results to Group 1 (NaOCl), but there was no significance between the treated groups. SEM images showed that Group 4 (PDT+Chitosan) showed the lowest area of contamination.

CONCLUSIONS

Combination of PDT and chitosan showed antibacterial potential against endodontic infection by E. faecalis.

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.

Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis

Aim:

To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum.

Methodology:

One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques.

Results:

Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V.

Conclusion:

Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration.