Candida albicans Virulence Factors and Pathogenicity for Endodontic Infections

Psidium guajava L. hydroethanolic extract as endodontic irrigant: phytochemical analysis, antioxidant activity, antimicrobial action and biocompatibility

Background

The search for novel antimicrobial agents in Endodontics is constant to overcoming persistent infections. Psidium guajava L. is a medicinal plant little explored in Endodontics. The aim of this study was to produce hydroethanolic extract of P. guajava L. and to evaluate its phytochemical composition, antimicrobial and antibiofilm action against standard and clinical strains of Enterococcus faecalis and Candida albicans, and cytotoxicity and genotoxicity on human keratinocyte cultures (HaCaT cells). The findings provide new insights into the potential of P. guajava as an alternative endodontic antimicrobial agent, contributing to the development of more effective and biocompatible therapeutic strategies.

Methods

P. guajava hydroethanolic extract was produced using young leaves of guajava and extracted using absolute ethanol and ultrapure water in a ratio (30 g:100 mL). The solid soluble, total flavonoid and total phenols content were determined. The chemical composition was determined via high-performance liquid chromatography (HPLC) analysis, then the free radical suppressive activity was assessed by determining the IC50 value, indicating the concentration required to eliminate 50% of free radicals. Later, the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the extract was evaluated against the strains using clinical and laboratory standards institute (CLSI) guidelines (M27-S4 and M7-A9). Then, the antibiofilm activity was evaluated via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. Finally, the cytotoxicity of the extract was evaluated via Alamar Blue assay, and the genotoxicity via micronucleus assay on human keratinocyte cultures (HaCaT cells). Data were analyzed using ANOVA and Tukey's test or Kruskal-Wallis and Dunn's test.

Results

The soluble solids content in the extract was 3.35%. Using the quercetin standard curve, the total flavonoid concentration was 0.130 ± 0.110 mg/mL. In addition, using standard curve for phenolic acids, the total phenolic concentration was 1.770 ± 1.540 mg/mL. HPLC analysis revealed peaks of rutin, quercetin and kaempferol as major flavonoids in the P. guajava L. extract. The extract demonstrated notable antioxidant activity, with an IC50 value of 10.39 µg/mL. The MMC values ranged 1.04-8.37 mg/mL. The extract at 8.37 mg/mL was effective in reducing the biofilms of standard and clinical strains of E. faecalis and C. albicans after 10 min. Cytotoxicity analysis revealed that all tested concentrations exhibited relatively low toxicity toward HaCaT cells. Genotoxicity assessment via the micronucleus assay indicated minimal DNA damage at all tested concentrations. Overall, P. guajava L. hydroethanolic extract at 8.37 mg/mL is the most effective concentration in reducing the biofilm of the standard and clinical strains of E. faecalis and C. albicans, while maintaining biocompatibility with HaCaT cultures.

Microbiological and toxicity analyses of the synthetic polymer polyhexamethylene guanidine hydrochloride against endodontic microorganisms

Failures in endodontic treatments are common due to microbial resistance in the pulp canal. The study evaluated the in vitro activity of polyhexamethylene guanidine hydrochloride (PHMGH) against endodontic strains, as well as in vivo toxicity. Using minimum inhibitory concentration and minimum bactericidal concentration techniques, PHMGH was effective against all microorganisms, even at low concentrations. At 50.0 µg/mL, it inhibited Enterococcus faecalis; furthermore, when compared to chlorhexidine (CLX), it demonstrated values 19 times lower against Candida albicans. The polymer's activity was also determined by agar diffusion, evaluating products A (calcium hydroxide - Ca(OH)2, as a reference), B (Ca(OH)2 combined with physiological solution, reference with a vehicle), C (PHMGH 6.25%), D (PHMGH 3.125%), E (PHMGH 1.5625%), F (PHMGH 0.78125%), G (PHMGH 6.25% and Ca(OH)2), H (PHMGH 3.125% and Ca(OH)2), I (PHMGH 1.5625% and Ca(OH)2), J (PHMGH 0.78125% and Ca(OH)2), and K (positive control, CLX 0.12%). Products containing PHMGH were more effective than the references against all strains, and C, D, and G were more effective than CLX against Peptostreptococcus anaerobius, Actinomyces naeslundii, and Actinomyces viscosus. According to the fractional inhibitory concentration index, the combination of PHMGH and CLX showed indifference for Peptostreptococcus anaerobius, Actinomyces naeslundii, Actinomyces viscosus and Escherichia coli, antagonism for Candida albicans, and synergy for Enterococcus faecalis. The toxicity of PHMGH at different concentrations was tested in Caenorhabditis elegans and did not show lethality in nematodes, with the LC50 observed only at the highest concentration (100 µg/mL) after two days of exposure. It is suggested that PHMGH exhibited antimicrobial activity against endodontic strains and low toxicity, raising expectations for new preventive and therapeutic products in endodontics.

Genomics insights of candidiasis: mechanisms of pathogenicity and drug resistance

Candidiasis, a prevalent class of human infections caused by fungi belonging to the Candida genus, is garnering increasing attention due to its pathogenicity and the emergence of drug resistance. The advancement of genomics technologies has offered powerful tools for investigating the pathogenic mechanisms and drug resistance characteristics of Candida. This comprehensive review provides an overview of the applications of genomics in candidiasis research, encompassing genome sequencing, comparative genomics, and functional genomics, along with the pathogenic features and core virulence factors of Candida. Moreover, this review highlights the role of genomic variations in the emergence of drug resistance, further elucidating the evolutionary and adaptive mechanisms of Candida. In conclusion, the review underscores the current state of research and prospective avenues for exploration of candidiasis, providing a theoretical basis for clinical treatments and public health strategies.

Antibiofilm efficacy of plant extracts as root canal irrigants in endodontics: a systematic literature review

Background

To explore the antibiofilm efficacy of plant extracts against in vitro formed single and multispecies endodontic biofilms, in comparison to conventional root canal irrigants.

Methods

PubMed, Scopus, Web of Science, and EMBASE were searched up to April 2024. Studies investigating the antibiofilm efficacy, of at least one plant extract and one conventional root canal irrigant, against endodontic biofilms were reviewed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Data were extracted, and studies were critically assessed using the Joanna Briggs Institute checklist.

Results

Among 78 articles, eight articles met the criteria and were eventually included in this review. One study showed a high risk of bias, six showed a moderate risk of bias, and one showed a low risk. A total of twelve plant extracts were tested for their antibiofilm efficacy against eight different single-species biofilms and one multispecies biofilm. A combination of microscopy methods and culturing techniques was used for the assessment of their efficacies. Plant extracts exhibited either a biofilm disruption and/or inhibition of biofilm formation. Psidium cattleianum extract and Psidium guajava exhibited enhanced efficacy compared to Chlorhexidine and NaOCl, respectively. Allium sativum demonstrated comparable efficacy to NaOCl. Furthermore, the combination of Cymbopogon martinii essential oil and NaOCl was found to be more effective than either alone when tested on a multispecies biofilm. However, the other plant extracts, such as Mikania Sprengel, Salvadora persica, Camellia sinensis, and Vitis vinifera showed efficacy but were still inferior compared to the control group.

Conclusions

Overall, the tested plant extracts demonstrated promising potential for combating in vitro endodontic biofilms. In that context, integrating conventional therapy protocols with plant-inspired treatments may allow effective endodontic biofilm eradication. Hence, future research should focus on optimizing the synergistic combinations of these extracts with NaOCl to maximize the therapeutic outcomes. Heterogeneity amongst the studies prevented a meta-analysis.

The effect of AH26, Endoseal and ZOE sealers on Candida albicans and Enterococcus faecalis

Background

In the oral cavity, root canal treatment failure (endodontics) is often due to the persistence of microorganisms in the root canal system after treatment, or re-infection of the root due to insufficient flooding. In addition, microorganisms are essential for the development of peri radicular diseases and are one of the main factors related to root canal treatment failure. Microorganisms that are commonly isolated from teeth that have failed endodontic treatment include Enterococcus (E.) faecalis and Candida (C.) albicans. Bacterial infection is closely related to the failure of root canal treatment, and the use of root sealer with antimicrobial activity and biological compatibility is necessary for the success of root canal treatment. One of the main goals of endodontic treatment is to eliminate intracanal infection and root canal flooding in order to prevent re-infection. Therefore, the aim of the current study is to evaluate the antibacterial and antifungal activity of ZOE, AH26 and Endoseal sealers in vitro.

Methods

To study the effect of each sealer; AH26, ZOE and Endoseal on E. faecalis and C. albicans, 10 samples were considered. Firstly, the freshly prepared sealers were poured inside the microtube with nutrient broth and then 10 µl of E. faecalis and C. albicans suspensions were separately added into a microtube and were kept 24 hours in the incubator to grow.

Results

The data were analyzed with Kolmogrov-Smirnov test and SPSS Version 19. Our results demonstrated that the resistance rate of C. albicans to ZOE, Endoseal and AH26 sealers was 0%, 100% and 70%, respectively. These values for the E. faecalis was 80%, 100% and 40% respectively. The resistance was defined when the microorganism was growth in subculture in LB agar.

Conclusion

ZOE sealer has highest antimicrobial effect after that AH26 sealer and the least antimicrobial effect is related to Endoseal sealer.

Formulation and evaluation of Phaseolus lunatus seed coat mediated silver nanoparticles mouthwash: A comprehensive study on biomedical properties and toxicological assessment

Silver nanoparticles have promising therapeutic potential in the field of dentistry, as newly emerging oral therapeutics, in the form of mouthwashes based on silver nanoparticles, demonstrate significant potential for enhancing oral management thus the present investigation aims to formulate silver nanoparticles-based mouthwash from an aqueous extract of Phaseolus lunatus seed coat (PLSC) and evaluate its biomedical properties. The green synthesized AgNPs in the mouthwash were characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD). The formulated mouthwash was assessed for its anti-microbial activity using the agar well diffusion technique and time-kill curve assay. Its anti-inflammatory and anti-oxidant activities are assessed through egg albumin assay and hydrogen peroxide assays. The Cytotoxic effect of formulated mouthwash was assessed through a brine shrimp lethality assay and MTT assay over the human osteoblast cell line (MG-63). Furthermore, the study also assessed the toxicity effect of formulated mouthwash through zebrafish embryos. The results suggest that the green synthesized AgNPs were spherical and had an average size of 42 nm and the formulated mouthwash exhibited significant anti-microbial activity, anti-inflammatory, and antioxidant properties, making them a better candidate for oral health therapeutics. The Zebrafish embryo toxicology studies of mouthwash revealed a consistent lack of abnormalities and a good viability and hatchability rate and the cytotoxic effect shows less toxicity over brine shrimp and human osteoblast cells. In conclusion, PLSC-AgNPs mouthwash is a potential oral therapeutic option with minimal toxicity for better oral management.

A Comparison of Conventional Root Canal Sealers With Ones That Use Green Synthesized Nanoparticles for Antimicrobial Activity: Protocol for a Systematic Review

BACKGROUND

Root canal failure and secondary endodontic infection are frequent clinical scenarios in dentistry. The main microorganisms implicated in root canal therapy failure are persistent Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. To combat the impact of disease resistance, scientists are concentrating on alternative antimicrobial root canal sealers. Nanomaterials are a recent development in endodontic materials that exhibit great antimicrobial properties, making them an ideal material choice for root canal sealers.

OBJECTIVE

This systematic review aims to compare the antimicrobial properties of conventional root canal sealers to those incorporating green synthesized nanoparticles between 2010 and 2024.

METHODS

A well-constructed protocol was established and registered with PROSPERO (CRD42021286373). Ethics approval was obtained from the Biomedical Research and Ethics Committee from the University of the Western Cape (UWC; BM22/1/4). PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) reporting guidelines were followed. The included criteria demonstrate the green synthesized nanoparticles studies where the nanoparticles (NPs) are incorporated in root canal sealers. MeSH (Medical Subject Headings) terms were used for the search strategy of the systematic electronic databases for articles published in English between 2010 and 2024. The selected databases included Scopus, PubMed, Web of Science, Science Direct, EBSCOhost, SpringerLink, and Wiley Online. A quality assessment tool for laboratory studies will be used to critically appraise the included studies. If applicable, statistical measures (mean, SD, etc) will be used for data analysis and presentation of the results.

RESULTS

The protocol is registered with PROSPERO. A preliminary search was conducted using a determined search strategy across 8 electronic databases, and the review is now complete.

CONCLUSIONS

It is anticipated that the results of this systematic review may reveal the increased interest and application for nanoparticle-enhanced root canal sealers. This will aid in the future development of root canal sealants and mitigate the risk of endodontic failure.

TRIAL REGISTRATION

PROSPERO CRD42021286373; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=286373.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51351.

Comparative analysis of hydrophobicity and dentin adhesion ability in Candida albicans strains

OBJECTIVE

Adhesion to dentin is a first step for a successful microbial root canal colonization. Cell hydrophobicity seems to have some influence in the Candida species adhesion to surfaces. To measure cell surface hydrophobicity and to investigate the adherence ability to human dentin among Candida albicans strains isolated from root canal and lingual dorsum via an in vitro study.

METHODOLOGY

adhesion was quantified in function of dentin area covered by blastospores and/or hyphae presence detected by epifluorescence microscope. Cell surface hydrophobicity was estimated by assessing the percentage migration of cells from an aqueous phase to a hydrocarbon phase. Contact angles were measured by the sessile drop technique on the dentin surface using a contact angle measurements apparatus. We also examined the correlation between adhesion ability and hydrophobicity.

RESULTS

although there was some intra-species variation in cell surface hydrophobicity, most isolates were characterized by moderate hydrophobicity. There was no significant difference in this parameter when the isolation niche was considered. Both root canal and lingual dorsum yeasts were able to adhere to dentin. No association was found between the strains' site of isolation and adhesion. Moreover, cell surface hydrophobicity and adhesion ability were not correlated.

CONCLUSION

although hydrophobicity can influence Candida albicans virulence in many ways, this study suggests that this parameter by itself was not a good predictor of adhesion to dentin.

Improving the Antimicrobial Potency of Berberine for Endodontic Canal Irrigation Using Polymeric Nanoparticles

To address the challenges posed by biofilm presence and achieve a substantial reduction in bacterial load within root canals during endodontic treatment, various irrigants, including nanoparticle suspensions, have been recommended. Berberine (BBR), a natural alkaloid derived from various plants, has demonstrated potential applications in dentistry treatments due to its prominent antimicrobial, anti-inflammatory, and antioxidant properties. This study aimed to produce and characterize a novel polymeric nanoparticle of poly (lactic-co-glycolic acid) (PLGA) loaded with berberine and evaluate its antimicrobial activity against relevant endodontic pathogens, Enterococcus faecalis, and Candida albicans. Additionally, its cytocompatibility using gingival fibroblasts was assessed. The polymeric nanoparticle was prepared by the nanoprecipitation method. Physicochemical characterization revealed spheric nanoparticles around 140 nm with ca, -6 mV of surface charge, which was unaffected by the presence of BBR. The alkaloid was successfully incorporated at an encapsulation efficiency of 77% and the designed nanoparticles were stable upon 20 weeks of storage at 4 °C and 25 °C. Free BBR reduced planktonic growth at ≥125 μg/mL. Upon incorporation into PLGA nanoparticles, 20 μg/mL of [BBR]-loaded nanoparticles lead to a significant reduction, after 1 h of contact, of both planktonic bacteria and yeast. Sessile cells within biofilms were also considered. At 30 and 40 μg/mL, [BBR]-loaded PLGA nanoparticles reduced the viability of the sessile endodontic bacteria, upon 24 h of exposure. The cytotoxicity of BBR-loaded nanoparticles to oral fibroblasts was negligible. The novel berberine-loaded polymeric nanoparticles hold potential as a promising supplementary approach in the treatment of endodontic infections.

Leaf Extracts of Moringa oleifera Cultivated in Baghdad: Characterization and Antimicrobial Potential against Endodontic Pathogens

The use of medicinal plant preparations to clean and disinfect root canal infection is gaining popularity. The aim of this study was to evaluate the bioactive composition of leaf extracts of Moringa oleifera plants cultivated in Iraq (specifically Baghdad) and their antimicrobial activity against selected root canal pathogens for potential application in endodontic treatment. Materials and Methods. Moringa leaf extracts were prepared either through cold maceration or warm digestion techniques to perform an ethanolic or aqueous extraction, respectively. Phytochemical detection was performed before thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) to measure flavonoids and phenolic compounds within both extracts. Then, their antimicrobial activities were investigated against Streptococcus mutans, Enterococcus faecalis, and Candida albicans through minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and agar well diffusion assay in comparison to NaOCl and Ca(OH)2. Results. Phytochemical screening showed several active ingredients but with higher expression of flavonoids and phenolic compounds. Also, different types of these compounds were detected through TLC and quantified by HPLC. MIC values for ethanolic extract against Streptococcus mutans, Enterococcus faecalis, and Candida albicans were 60, 65, and 55, respectively, while for aqueous extract, MIC values were 70, 80, and 50, respectively. Aqueous extract showed a higher inhibition zone than ethanolic extract for both Streptococcus mutans and Enterococcus faecalis with a statistically significant difference (p ≤ 0.001) for all tested materials except with NaOCl and Ca(OH)2 in Streptococcus mutans and Enterococcus faecalis, respectively. The ethanolic extract showed a higher inhibition zone against Candida albicans, with a statistically significant difference (p ≤ 0.001) for all tested materials. Conclusion. Ethanolic and aqueous extracts of Moringa oleifera leaves cultivated in Baghdad contain considerable quantities of phytochemicals, especially flavonoid and phenolic compounds, and demonstrated antimicrobial activities against selected endodontic pathogens. Therefore, Moringa leaf extracts could be suggested as an alternative antimicrobial material in endodontic treatment.

The Effect of Different Compositions and Concentrations of Etidronate-Containing Irrigants on the Antibacterial Activity of Sodium Hypochlorite against Enterococcus faecalis and Candida albicans

We assessed the effect of different compositions and concentrations of two etidronate-containing irrigants on the antibacterial activity of sodium hypochlorite (SH) against Enterococcus faecalis and Candida albicans in vitro. Pure cultures of C. albicans and E. faecalis were isolated from root canal samples. The disc diffusion method was used to compare the antibacterial effect of pure SH and SH mixed with 9%, 15%, and 18% etidronate of two manufactures (dual rinse (DR); IsraDent (ID)) and EDTA. The pH and temperature of the solutions were measured immediately after mixing and within 40 min. The ANOVA revealed a significant influence of the type of irrigating solution on the C. albicans and E. faecalis inhibition zone diameters that ranged from 6.6 to 51.6 mm and from 6.4 to 12.4 mm, respectively. SH with DR 9% exhibited the highest effect against C. albicans. The antifungal activity of the other irrigants was SH = SH + DR15% = SH + DR18% = SH + ID9% > SH + EDTA > SH + ID15% > SH + ID18%. No significant differences in the anti-E. faecalis effect were revealed between the tested solutions except for the mixtures of SH and 15% and 18% ID, which exhibited no antiseptic effect. There was a strong positive correlation between antiseptic activity against both microorganisms and the pH values of the tested solutions. In conclusion, most etidronate formulations did not significantly hamper sodium hypochlorite activity against C. albicans and E. faecalis. The effect was concentration- and manufacturer-dependent.

Antifungal and genotoxic effects of Thymus serpyllum as a root canal irrigant

OBJECTIVES

The aim of this study was the assessment of the efficiency of the ethyl acetate (EthOAc) extract of Thymus serpyllum against Candida albicans and to compare it with sodium hypochlorite (NaOCl) and chlorhexidine (CHX), as well as their genotoxic effect.

MATERIAL AND METHODS

The antifungal effectiveness of the EthOAc extract of Thymus serpyllum was determined using the agar disk diffusion method. The inhibition zones induced by the EthOAc extract were compared after 5 min, 60 min, and 24 h to those induced by standard solutions (2% CHX and 2% NaOCl). An in vitro genotoxicity assay was performed in cultured lymphocytes from the blood of human volunteers to observe micronuclei formation. Statistical analysis of the results was performed using the Kruskal-Wallis test and one-way analysis of variance.

RESULTS

The inhibition zone of combination of CHX with EthOAc extract of Thymus serpyllum against C. albicans was 29.7 mm after 5 min, 28.3 mm after 60 min, and 29 mm after 24 h. The inhibition zone of NaOCl in combination with EthOAc extract of Thymus serpyllum against C. albicans was 0 mm. The EthOAc extract of Thymus serpyllum did not show a genotoxic effect on lymphocyte cells.

CONCLUSIONS

The EthOAc extract of Thymus serpyllum in combination with CHX may be a useful root canal disinfection in endodontic therapy.

The Effectiveness of Silver Nanoparticles Mixed with Calcium Hydroxide against Candida albicans: An Ex Vivo Analysis

INTRODUCTION

The purpose of this study was to assess the antifungal activity of silver nanoparticles (AgNPs) in combination with calcium hydroxide (Ca(OH)2) against Candida albicans (C. albicans).

METHODS

AgNPs was mixed with pure Ca(OH)2 powder in an aqueous base. A standard suspension (1 × 108 bacterial cells/mL) of C. albicans was prepared in a 96-well plate and incubated on shaker at 37 °C in 100% humidity to allow fungal biofilm formation in infected dentin slices (n = 98). The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of AgNPs alone or with Ca(OH)2 were determined. The samples were separately placed in 24-well tissue culture plates and divided into three experimental groups (0.03, 0.04, and 0.06) and three control groups; negative (saline) and positive chlorhexidine gel and Ca(OH)2. Quantitative measurements of fungal activity by XTT colorimetric assay and qualitative measurements using confocal laser microscopy and scanning electron microscopy were performed.

RESULTS

The cell viability of C. albicans in the experimental groups was significantly reduced compared to the negative control group. The combination of (AgNPs (0.04%) and Ca(OH)2) was the most potent against C. albicans.

CONCLUSIONS

The findings demonstrated that combining silver nanoparticles with Ca(OH)2 was more effective against C. albicans biofilm compared to Ca(OH)2 alone, suggesting a combing effect.

Green Synthesized Polymeric Iodophors with Thyme as Antimicrobial Agents

Antimicrobial resistance (AMR) is a growing concern for the future of mankind. Common antibiotics fail in the treatment of microbial infections at an alarming rate. Morbidity and mortality rates increase, especially among immune-compromised populations. Medicinal plants and their essential oils, as well as iodine could be potential solutions against resistant pathogens. These natural antimicrobials abate microbial proliferation, especially in synergistic combinations. We performed a simple, one-pot synthesis to prepare our formulation with polyvinylpyrrolidone (PVP)-complexed iodine (I2), Thymus Vulgaris L. (Thyme), and Aloe Barbadensis Miller (AV). SEM/EDS, UV-vis, Raman, FTIR, and XRD analyses verified the purity, composition, and morphology of AV-PVP-Thyme-I2. We investigated the inhibitory action of the bio-formulation AV-PVP-Thyme-I2 against 10 selected reference pathogens on impregnated sterile discs, surgical sutures, cotton gauze bandages, surgical face masks, and KN95 masks. The antimicrobial properties of AV-PVP-Thyme-I2 were studied by disc diffusion methods and compared with those of the antibiotics gentamycin and nystatin. The results confirm AV-PVP-Thyme-I2 as a strong antifungal and antibacterial agent against the majority of the tested microorganisms with excellent results on cotton bandages and face masks. After storing AV-PVP-Thyme-I2 for 18 months, the inhibitory action was augmented compared to the fresh formulation. Consequently, we suggest AV-PVP-Thyme-I2 as an antimicrobial agent against wound infections and a spray-on contact killing agent.

Comparative evaluation of antimicrobial efficacy of 3C antibiotic paste with triple antibiotic paste as root canal filling material for primary teeth: An in-vitro study

Root canal infection in primary teeth is polymicrobial in nature. Most resistant micro-organisms, such as E.faecalis survive in chronic infection of the root canal at the periapical area and are difficult to remove by various root canal irrigants. C.albicans has been found in chronic infections of root canals of primary teeth due to its ability to invade dentinal tubules. The multiple bacteria strains which cause endodontic infections, make it difficult to clean root canals with a single effective antibiotic. Hence Triple Antibiotic Paste (TAP) has been previously introduced, consisting of ciprofloxacin, metronidazole, and minocycline. Although this mixture aids in pulp regeneration and has been used to disinfect root canal systems, it is linked to tooth discolouration. The aim of this study is to evaluate and compare the antimicrobial efficacy of a newly formulated 3C antibiotic paste (consisting of Ciprofloxacin, Clindamycin, and Cefaclor) with conventional TAP against E. faecalis and C. albicans. In this in-vitro laboratory study, pure culture of C. albicans and E. faecalis will be grown on Sabouraud's dextrose agar (SD) agar and Brain heart infusion agar (BHI) agar respectively and will be suspended for 24 hours at 37°C. For comparison of antimicrobial efficacy, the zone of inhibition will be for the 3C antibiotic paste against conventional TAP (control) for E. faecalis and C. albicans, and will be determined using digital calliper in millimetre after every 24 and 72 hours. We hypothesise that the newly formulated 3C paste will have better antimicrobial efficacy when compared with conventional TAP. It is expected that a newly formulated 3C paste will prove to be the successful as root canal filling material for primary teeth.

In Vitro Evaluation of Smear Layer and Debris Removal and Antimicrobial Activity of Different Irrigating Solutions

OBJECTIVE

The aim of this in vitro study was to compare the smear layer and debris removal and antimicrobial activity of two dual-action irrigating solutions for continuous chelation (Triton; Brasseler, Savannah, USA and Dual Rinse HEDP; Medcem GmbH, Weinfelden, Switzerland) with a dual step irrigation protocol with sodium hypochlorite (NaOCl) followed by ethylenediaminetetraacetic acid (EDTA).

METHODS

Thirty single-rooted single-canal teeth were divided into three groups (n=10) and irrigated with Triton, Dual Rinse HEDP mixed with 6% NaOCl and 6% NaOCl/17% EDTA. The teeth were observed under a scanning electron microscope (SEM) to assess the canal wall cleanliness. In addition, 80 dentine discs were contaminated with Candida albicans and 80 discs with Enterococcus faecalis and irrigated with Triton, Dual Rinse HEDP mixed with 6% NaOCl and 6% NaOCl/17% EDTA or not treated (n=20). Fifteen discs were used to evaluate colony-forming units, while 5 discs were analysed by SEM. Data were analysed using the Shapiro- Wilk, Kruskal-Wallis and One-Way ANOVA tests.

RESULTS

Triton was statistically more effective than Dual Rinse HEDP and NaOCl/EDTA in removing debris (p<0.05), except with NaOCl/EDTA in the coronal third. Triton was more effective than Dual Rinse HEDP in removing the smear layer from the apical and middle thirds (p<0.05). All the irrigation protocols significantly re- duced the number of E. faecalis. The Triton group showed the lowest number of remaining C. albicans (p<0.05).

CONCLUSION

Triton was the most effective irrigation solution in removing debris and as effective as NaOCl/ EDTA in removing the smear layer. Triton showed the highest efficacy against C. albicans. New irrigating solutions that provide continuous chelation may provide an alternative to current irrigation protocols.

In vitro evaluation of three engineered multispecies endodontic biofilms on a dentinal disk substrate

The aim of this study was the development of a complex multispecies endodontic biofilm using Candida albicans, Proteus mirabilis and Pseudomonas aeruginosa on a biofilm of Enterococcus faecalis in a dentinal substrate design. The endodontic pathology is a biofilm-mediated infection, and the aim of root canal therapy is to reduce, as much as possible, the bacterial population. Thus, it is important to develop a laboratory endodontic biofilm to test the effect of new irrigation and obturation techniques on reduction of bacterial count. The culture of Enterococcus faecalis from ATCC 29212 began with aerobic cultivation on blood agar, followed by transfer to Brain Heart Infusion (BHI) broth with 5% sucrose. Incubation occurred in a shaker at 37 °C for 24 h, followed by an additional 24-h static phase. After 10 d, Proteus mirabilis, Pseudomonas aeruginosa, and Candida albicans were introduced sequentially in three distinct groups. Group 1: the order of addition was Candida albicans, Proteus mirabilis, and Pseudomonas aeruginosa; Group 2: the order was Pseudomonas aeruginosa, Candida albicans, and Proteus mirabilis; and Group 3: Proteus mirabilis, Pseudomonas aeruginosa, and Candida albicans. After 16 days, the biofilm was carefully extracted, transferred to sterile BHI, and dissected using a sterile needle technique. Subsequently, an optical density test, bacterial counts, and colony enumeration were performed on various agar plates. Group 2 in which Pseudomonas aeruginosa was added directly after Enterococcus faecalis followed by Candida albicans and Proteus mirabilis showed significantly greater total bacterial count than the other two groups.

Molecular Identification of Candida albicans in Endodontic Retreatment Cases by SYBR Green I Real-time Polymerase Chain Reaction and its Association with Endodontic Symptoms

Statement of the Problem

Recent microbiological studies have expressed ever-increasing concerns about Candida albicans as a causal factor in the failure of endodontic treatments. Real-time quantitative polymerase chain reaction (qPCR), including the SYBR Green I system, is a technique in which a fluorescent dye is incorporated into the double-stranded DNA that is produced during DNA polymerase activity.

Purpose

This study aimed to determine the relative prevalence of Candida albicans in root canals of retreatment cases and its association with endodontic symptoms.

Materials and Method

In the present cross-sectional/analytical study fifty subjects were selected. Clinical features and radiographic status of the teeth were also evaluated. After access cavity preparation, the retrieved material and dentinal chips removed from the root canal were transferred into 1.5-mL microtubes, followed by storage at -20ºC until used for DNA extraction. A DNeasy Tissue Kit was used to extract DNA using the DNeasy protocol for animal tissues. Master Plus SYBR Green I (Jena Bioscience, Germany) was used in a Rotor-gene Real-time PCR System for real-time PCR. The relationship between the presence of Candida albicans and the clinical and radiographic features were analyzed using McNemar's test.

Results

There was a significant relationship between the radiographic findings in endodontically treated teeth and the presence of Candida albicans. However, there was no significant relationship between the presence of Candida albicans and any of the clinical symptoms.

Conclusion

In spite of the limitations of this study, we concluded that Candida albicans was associated with root canal infections in endodontic retreatment cases, but there was no relationship between root canal infections and the clinical symptoms.

Multispecies oral biofilm and identification of components as treatment target

Endodontic infections involve a multispecies biofilm, making it difficult to choose an antimicrobial treatment. Characteristics such as the pathogens involved and number of microorganisms, nutrients, material surface to develop the biofilm, flow and oxygenation conditions are important for biofilm development using in vitro models.

OBJECTIVE

To develop a standardized biofilm model, which replicates the main features (chemical, microbiological, and topographical) of an infected root canal tooth to detect components as treatment target.

DESIGN

Clinical strains of Enterococcus faecalis, Candida albicans, and Actinomyces israelii were isolated, and a multispecies biofilm was developed using continuous laminar flow reactors under anaerobic conditions in human dental roots. The microbiological composition was determined by counting colony-forming units and scanning electron microscope micrographs. In addition, the chemical composition of the exopolymeric matrix was determined by vibrational Raman spectroscopy and liquid chromatography of biofilm supernatant treated with enzyme.

RESULTS

E. faecalis turned out to be the main microorganism in mature biofilm, this was related to the presence of β-galactosidase detected by vibrational Raman spectroscopy. After the enzymatic treatment of the extracellular polymeric substance, the presence of mannose and glucose was established.

CONCLUSIONS

The present work contributes to better understanding of standard conditions to develop a multispecies biofilm in human dental roots, which could have an impact on the generation of new root canal disinfection techniques in endodontic pathologies.

Sub-lethal concentrations of chlorhexidine inhibit Candida albicans growth by disrupting ROS and metal ion homeostasis

Candida albicans is a normal resident of the human oral cavity. It is also the most common fungal pathogen, causing various oral diseases, particularly in immunocompromised individuals. Chlorhexidine digluconate (CHG) is a broad-spectrum antimicrobial agent widely used in dental practice and has been recommended to treat oral candidiasis. However, its action mechanism against the fungal pathogen C. albicans remains poorly understood. The aim of the present study was to investigate the effect of CHG at sub-lethal concentrations against C. albicans. CHG inhibited the growth of C. albicans in a dose- and time-dependent manner. Cells treated with CHG exhibited altered membrane permeability, reduced metabolic activity, and enhanced metal ion and reactive oxygen species (ROS) accumulation. Copper-sensing transcription factor Mac1, iron-sensing transcription factors Sfu1 and Sef2, and copper transporter Ctr1 regulated intracellular metal ion and ROS homeostasis in response to CHG. Deletion of MAC1, SFU1, or SEF2 increased intracellular ROS production and cell susceptibility to CHG. This study revealed a novel mechanism by which CHG induced apoptosis of C. albicans cells through the disruption of metal ion and ROS homeostasis, which may help to identify new targets for fungal infections.

Molecular Detection of Secreted Aspartyl Proteinases (Saps) From Dental Isolates of Candida albicans and Targeting With Psidium guajava Biocompounds: An In Vitro and In Silico Analysis

Introduction Candida albicans (C. albicans) is an opportunistic yeast-like fungus and is considered a functional biome of the oral and gut microbiomes. The sap gene and its types play a vital role in the pathogenesis of C. albicans. The emergence of resistance traits is a major problem, and targeting the same with alternative medicines has sparked renewed interest in recent years. Objectives This study is thus aimed at detecting the frequency of sap gene types in the clinical isolates of C. albicans and evaluating the antifungal effect of the crude methanolic extract of Psidium guajava (P. guajava). Further in silico assessments will assess the inhibitory effect of six compounds of P. guajava against the Sap protein. Materials and methods C. albicans was characterized phenotypically in 20 patients with root caries, and the sap gene was detected by PCR. The crude methanolic extract was prepared, and its antifungal efficacy was evaluated by the agar well diffusion method. Auto-docking was performed to assess the best compound based on the docking and overall interactions. Results Six isolates were identified as C. albicans and sap gene types 1-3 were detected in the four strains. P. guajava methanolic extracts showed a promising antifungal effect at varying concentrations. In silico analysis showed myricetin possessing the maximum number of hydrogen bonds and high docking energy with one violation. Conclusion The study concludes that P. guajava has a promising inhibitory effect against C. albicans with myricetin as the best compound to target the sap gene of C. albicans. However, further experimental studies are to be considered for its effectiveness in treating the infections caused by C. albicans.

Mining the nanotube-forming Bacillus amyloliquefaciens MR14M3 genome for determining anti-Candida auris and anti-Candida albicans potential by pathogenicity and comparative genomics analysis

There is a global health concern associated with the emergence of the multidrug-resistant (MDR) fungus Candida auris, which has significant mortality rates. Finding innovative and distinctive anti-Candida compounds is essential for treating infections caused by MDR C. auris. A bacterial strain with anti-Candida activity was isolated and identified using 16 S rRNA gene sequencing. The whole genome was sequenced to identify biosynthesis-related gene clusters. The pathogenicity and cytotoxicity of the isolate were analyzed in Candida and HFF-1 cell lines, respectively. This study set out to show that whole-genome sequencing, cytotoxicity testing, and pathogenicity analysis combined with genome mining and comparative genomics can successfully identify biosynthesis-related gene clusters in native bacterial isolates that encode antifungal natural compounds active against Candida albicans and C. auris. The native isolate MR14M3 has the ability to inhibit C. auris (zone of inhibition 25 mm) and C. albicans (zone of inhibition 25 mm). The 16 S rRNA gene sequence of MR14M3 aligned with Bacillus amyloliquefaciens with similarity (100%). Bacillus amyloliquefaciens MR14M3 establishes bridges of intercellular nanotubes (L 258.56 ± 35.83 nm; W 25.32 ± 6.09 nm) connecting neighboring cells. Candida cell size was reduced significantly, and crushed phenotypes were observed upon treatment with the defused metabolites of B. amyloliquefaciens MR14M3. Furthermore, the pathogenicity of B. amyloliquefaciens MR14M3 on Candida cells was observed through cell membrane disruption and lysed yeast cells. The whole-genome alignment of the MR14M3 genome (3981,643 bp) using 100 genes confirmed its affiliation with Bacillus amyloliquefaciens. Genome mining analysis revealed that MR14M3-coded secondary metabolites are involved in the biosynthesis of polyketides (PKs) and nonribosomal peptide synthases (NRPSs), including 11 biosynthesis-related gene clusters with one hundred percent similarity. Highly conserved biosynthesis-related gene clusters with anti-C. albicans and anti-C. auris potentials and cytotoxic-free activity of B. amyloliquefaciens MR14M3 proposes the utilization of Bacillus amyloliquefaciens MR14M3 as a biofactory for an anti-Candida auris and anti-C. albicans compound synthesizer.

Direct and residual antimicrobial effect of 2% chlorhexidine gel, double antibiotic paste and chitosan- chlorhexidine nanoparticles as intracanal medicaments against Enterococcus faecalis and Candida albicans in primary molars: an in-vitro study

BACKGROUND

Thorough disinfection of root canals in primary molars may be complicated by the complex root canal morphology. This in-vitro study aimed to compare direct and residual antimicrobial effect of 2% chlorhexidine (CHX) gel, 500 mg/ml double antibiotic paste (DAP) and chitosan-chlorhexidine nanoparticles (CS-CHX NPs) as intracanal medicaments against Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans) in primary molars.

METHODS

Mesial roots of 63 mandibular second primary molars were infected with E. faecalis and C. albicans. Teeth were divided into 9 groups: Ia: (CS-CHX NPs), IIa: (CHX), IIIa: (DAP), IVa: chitosan nanoparticles (CSNPs) in which medicaments were placed for 3 days, groups Ib: (CS-CHX NPs), IIb: CHX, IIIb: (DAP), IVb: (CSNPs) in which medicaments were placed for 7 days, and Group V (control): teeth were infected, irrigated with saline, and sampled 3- and 7-days post-infection. Microbiological samples were obtained after infection, 3, and 7 days after medicament placement and 7 days after medicament removal for both time points. One-way ANOVA, Tukey's post hoc test and paired t-test were used at p < 0.05.

RESULTS

CS-CHX NPs had the highest anticandidal effect which was comparable to CHX and significantly higher than other medicaments (p < 0.001) at both time points. CS-CHX NPs had the highest effect against E. faecalis which was comparable to DAP and significantly higher than other medicaments (p < 0.001) at 3 days. All medicaments showed similar effect against E. faecalis after 7 days. The 7-days placement significantly increased the antimicrobial effect against both micro-organisms in all groups, except CS-CHX NPs which showed an insignificant increase. CS-CHX NPs showed the highest residual effect against both micro-organisms that increased with 7-days placement.

CONCLUSION

CSNPs and CHX combination showed a synergistic effect against both micro-organisms. CS-CHX NPs displayed a higher effect at a shorter period compared to other medicaments, yet its residual effect was higher with 7-days placement.

Non-Thermal Atmospheric Pressure Plasma Application in Endodontics

The failure of endodontic treatment is frequently associated with the presence of remaining microorganisms, mainly due to the difficulty of eliminating the biofilm and the limitation of conventional irrigation solutions. Non-thermal atmospheric pressure plasma (NTPP) has been suggested for many applications in the medical field and can be applied directly to biological surfaces or indirectly through activated liquids. This literature review aims to evaluate the potential of NTPP application in Endodontics. A search in the databases Lilacs, Pubmed, and Ebsco was performed. Seventeen manuscripts published between 2007 and 2022 that followed our established inclusion criteria were found. The selected manuscripts evaluated the use of NTPP regarding its antimicrobial activity, in the direct exposure and indirect method, i.e., plasma-activated liquid. Of these, 15 used direct exposure. Different parameters, such as working gas and distance from the apparatus to the substrate, were evaluated in vitro and ex vivo. NTPP showed a disinfection property against important endodontic microorganisms, mainly Enterococcus faecalis and Candida albicans. The antimicrobial potential was dependent on plasma exposure time, with the highest antimicrobial effects over eight minutes of exposure. Interestingly, the association of NTPP and conventional antimicrobial solutions, in general, was shown to be more effective than both treatments separately. This association showed antimicrobial results with a short plasma exposure time, what could be interesting in clinical practice. However, considering the lack of standardization of the direct exposure parameters and few studies about plasma-activated liquids, more studies in the area for endodontic purposes are still required.

Efficacy of Endodontic Disinfection Protocols in an E. faecalis Biofilm Model-Using DAPI Staining and SEM

The aim of this study was to investigate the antimicrobial efficacy of different disinfection protocols in a novel Enterococcus faecalis biofilm model based on a visualization method and to evaluate the potential alteration of dentinal surface. A total of 120 extracted human premolars were allocated to 6 groups with different irrigation protocols. The assessment of the effectiveness of each protocol and the alteration of dentinal surface were visualized by using SEM and fluorescence microscopy (DAPI). A dense E. faecalis biofilm with a penetration depth of 289 μm (medial part of the root canal) and 93 μm (apical part) validated that the biofilm model had been successfully implemented. A significant difference between the 3% NaOCl groups and all the other groups in both observed parts of the root canal (p < 0.05) was detected. However, the SEM analysis revealed that the dentinal surface in the 3% NaOCl groups was severely altered. The established biofilm model and the visualization method based on DAPI are appropriate for bacterial quantification and evaluation of the depth effect of different disinfection protocols in the root canal system. The combination of 3% NaOCl with 20% EDTA or MTAD with PUI allows the decontamination of deeper dentine zones within the root canal but simultaneously alters the dentinal surface.

In vitro antifungal and antibiofilm activities of novel sulfonyl hydrazone derivatives against Candida spp

BACKGROUND

The aim of this study was to investigate the antifungal and antibiofilm activity of the new sulfonyl hydrazones compound derived from sulphonamides.

METHODS

In this study, new sulfonyl hydrazone series were synthesized via a green chemistry method. The structures of the synthesized compounds were characterized by elemental analyses and spectroscopic methods. The antifungal activities of the Anaf compounds against Candida strains under planktonic conditions were tested. The biofilm-forming ability of Candida strains was determined and the inhibitory effects of Anaf compounds on Candida biofilms compared with fluconazole were measured by MTT assay. Expression analysis of biofilm-related genes was investigated with qRT-PCR. The statistical analysis was performed using a one-way ANOVA test. CANDIDA: strains was determined and the inhibitory effects of Anaf compounds on Candida biofilms compared with fluconazole were measured by MTT assay. Expression analysis of biofilm-related genes was investigated with qRT-PCR. The statistical analysis was performed using a one-way ANOVA test.

RESULTS

A total of 16 (45.7%) out of 35 Candida isolates were determined as strong biofilm producers in this study. C. albicans was the most biofilm producer, followed by C. krusei and C. lusitaniae. The Anaf compounds had a broad spectrum of activity with MIC values ranging from 4 μg/ml to 64 μg/ml. Our data indicated that the Anaf compound had a significant effect on inhibiting biofilm formation in both fluconazole-susceptible and -resistant strains. The expression levels of hypha-specific genes als3, hwp1, ece1 and sap5 were downregulated by Anaf compounds.

CONCLUSIONS

Our study revealed that the Anaf compounds had antifungal activity and inhibited fungal biofilms, which may be related to the suppression of C. albicans adherence and hyphal formation. These results suggest that Anaf compounds may have therapeutic potential for the treatment and prevention of biofilm-associated Candida infections.

Gene expression analysis of toll like receptor 2 and 4, Dectin-1, Osteopontin and inflammatory cytokines in human dental pulp ex-vivo

BACKGROUND

Toll like receptors (TLR) 2 and 4 present on innate immune cells of the dental pulp detect cariogenic bacteria. Along with bacteria, C. albicans may also be present in dental caries. The presence of C. albicans can be detected by Dectin-1 a C type Lectin receptor. Expression of Dectin-1 in human pulpits has not been reported. Similarly, cytokines are released as a consequence of dental pulp inflammation caused by cariogenic bacteria. The T helper (Th) 1 inflammatory response leads to exacerbation of inflammation and its relationship with Osteopontin (OPN) is not known in pulp inflammation.

OBJECTIVE

The aim of this study was to observe the expression of Dectin-1, TLR-2, OPN and pro-inflammatory cytokines in irreversibly inflamed human dental pulp and to observe relationship between Dectin-1/TLR-2 and OPN/Pro-inflammatory cytokines in the presence of appropriate controls.

METHODS

A total of 28 subjects diagnosed with irreversible pulpitis were included in this ex-vivo study. Fifteen samples were subjected to standard hematoxylin and Eosin (H&E) and immunohistochemistry staining. Whereas, gene expression analysis was performed on 13 samples to observe mRNA expression of pro-inflammatory cytokines; tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1 beta (ß), IL-6 Dectin-1, OPN, TLR-2 and TLR-4. SPSS version 21 was used for statistical analysis. One way analysis of variance (ANOVA), Pearson correlation and Chi-square test were used at p ≤ 0.05.

RESULTS

Gene expressions of Dectin-1, TLR-2 and TLR-4 were observed in all samples. Dectin-1 and TLR-2 expressions were significantly correlated (r = 0.5587, p = 0.0002). Similarly, OPN and TNF-α expression showed a significant correlation (r = 0.5860, p = 0001). The agreement between histologic and clinical diagnosis was 69.2% in the cases of irreversible pulpitis.

CONCLUSION

Dectin-1 was expressed by inflamed human dental pulp. Dectin-1 and TLR-2 expression pattern was suggestive of a collaborative receptor response in inflamed pulp environment. OPN and TNF-α expressions showed a positive correlation indicating a possible relationship.

Comparative evaluation of the antifungal efficacy of sodium hypochlorite, chlorhexidine, and silver nanoparticles against Candida albicans

Candida albicans is a microorganism that causes root canal infections. However, it cannot be eliminated with conventional irrigation solutions. Recently, silver nanoparticles (AgNPs) have become popular for their superior antimicrobial effects. The purpose of this study was to evaluate the antifungal effect of AgNPs to C. albicans comparing with 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX). Silver nanoparticles were synthesized by chemical reduction method. Minimum inhibitory concentration and minimum fungicidal concentration of AgNPs against C. albicans strain were determined according to microdilution method reported by Clinical Laboratory Standards Institute. C. albicans biofilm layer was formed on the dentin blocks for 10 days. The biofilm structure was observed by scanning electron microscopy. Statistical analysis was performed with one way analysis of variance analysis and group comparisons were performed with Tukey test. AgNPs showed the highest antifungal effect among the groups. 5.25% NaOCl showed the lowest antifungal effect among the groups. While the 2% CHX solution had a statistically lower antifungal effect than AgNPs, it was found to have a higher effect than NaOCl (p < .016). Nanoparticles present a wide research field as an alternative irrigation solution in root canal treatment. The antifungal effect of AgNPs against C. albicans was confirmed in this study. Further in vivo studies should evaluate the conditions of use and long-term prognosis of AgNPs.

Distinctive Detoxification: The Case for Including the Microbiome in Detox Strategy

Exposure to environmental toxins contributes to both acute and chronic illnesses, and is of growing concern. The importance of the microbiome to gastrointestinal (GI), as well as systemic health, has been the topic of much research recently. The microbiome influences health, and can either be a source of beneficial metabolites, or contribute to poor health. Dysbiosis, particularly in the GI tract, or oral cavity is a source of endogenously produced toxicity in the form of proinflammatory mediators-most notably lipopolysaccharide (LPS). LPS is cleared by the liver from enterohepatic circulation, and contributes to its workload. Bacterial overgrowth has been shown to be a contributing factor to liver disease. Further influences of the microbiome on detoxification include the Gut-Liver axis and biofilm production. Botanicals can have beneficial effects on microbial balance, favoring probiotic abundance, while addressing pathogen load. Additionally, plants offer antioxidant, biofilm disruption, antiinflammatory and immunomodulatory activities. Inclusion of botanical medicine to modulate the microbiome is a novel therapeutic target to reduce endogenously produced toxins and total toxic load.

New and Efficient Bioactive Glass Compositions for Controlling Endodontic Pathogens

Endodontic treatment aims to conserve teeth through removing infected tissue, disinfecting, and filling/sealing the root canal. One of the most important treatment steps is the removal of microorganisms to avoid reinfection and consequent tooth loss. Due to increased resistance to intracanal medications, new alternative procedures are needed. Thus, an intracanal medication is suggested using three bioactive glass (BG) compositions (BG1, BG2, and BG3) produced by the sol–gel method, with different molar contents of bactericidal oxides. The BGs were morphologically and physically characterized. Their ability to inhibit the growth of two oral pathogens responsible for the failure of endodontic treatments (E. faecalis and C. albicans) was also studied. The results suggest that BG2 and BG3 can inhibit the growth of E. faecalis after 48 h of incubation, and all BG samples have a significant effect on C. albicans survival.

Ceragenin CSA-44 as a Means to Control the Formation of the Biofilm on the Surface of Tooth and Composite Fillings

Recurrent oral infections, as manifested by endodontic and periodontal disease, are often caused by Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans). Here, we assessed the anti-biofilm activity of ceragenin CSA-44 against these microbes growing as a biofilm in the presence of saliva on the surface of human teeth and dental composite (composite filling) subjected to mechanical stresses. Methods: Biofilm mass analysis was performed using crystal violet (CV) staining. The morphology, viscoelastic properties of the biofilm after CSA-44 treatment, and changes in the surface of the composite in response to biofilm presence were determined by AFM microscopy. Results: CSA-44 prevented biofilm formation and reduced the mass of biofilm formed by tested microorganisms on teeth and dental composite. Conclusion: The ability of CSA-44 to prevent the formation and to reduce the presence of established biofilm on tooth and composite filling suggests that it can serve as an agent in the development of new methods of combating oral pathogens and reduce the severity of oral infections.

Evaluation of Antibacterial and Antifungal Effects of Calcium Hydroxide Mixed with Two Different Essential Oils

BACKGROUND

Calcium hydroxide is a routinely used material for root canal disinfection during root canal treatment. Natural products have great potential in terms of their antibacterial effects. This study aimed to establish an effective alternative intracanal medicament using Origanum dubium (O. dubium) and Mentha spicata (M. spicata) essential oils.

MATERIALS AND METHODS

O. dubium and M. spicata, collected from Lefke, Cyprus, were separately subjected to hydrodistillation. The obtained essential oil compositions were analysed simultaneously by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). The compositions were then divided into groups and mixed with calcium hydroxide at a 1:1 concentration; after that, the pastes were tested on Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans), which are the most common resistant pathogenic microorganisms in the root canal. The antibacterial activity of the pastes was measured using a disk diffusion assay.

RESULTS

The GC and GC-MS analyses revealed that O. dubium and M. spicata had major compositions of carvacrol (75.8%) and carvone (71.3%), respectively. Antimicrobial activity was found to be significantly higher when study groups with O. dubium essential oil were applied to both E. faecalis and C. albicans. The results also show that M. spicata, together with calcium hydroxide, demonstrated a significant antifungal effect on C. albicans when incubated for 72 h.

CONCLUSIONS

M. spicata was found to be an effective antimicrobial agent on C. albicans, whereas O. dubium was found to be very effective on both E. faecalis and C. albicans. These data demonstrate that these natural essential oils may be promising candidates for alternative intracanal medicament in future routine clinical applications.

Enterococcus faecalis and Candida albicans dual-species biofilm: establishment of an in vitro protocol and characterization

Enterococcus faecalis is the most important agent of persistent apical periodontitis, and recently, Candida albicans has also been implicated in periapical infections. This study aimed to optimize an in vitro E. faecalis and C. albicans dual-species biofilm protocol for endodontic research. Different physicochemical conditions for biofilm formation were tested. Susceptibility assays to antimicrobials, biochemical composition and an ultra-morphological structure analyses were performed. Reproducible dual-species biofilms were established in BHI medium at 35 °C, for 48 h and in a microaerophilic atmosphere. An increase in biomass and chitin content was detected after vancomycin treatment. Structural analysis revealed that the dual-species biofilm was formed by both microorganisms adhered to the substrate. The proposed protocol could be useful for the study of interkingdom relationships and help to find new strategies against periapical infections.

Nrf2 in the Field of Dentistry with Special Attention to NLRP3

The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health.

Effectiveness of antimicrobial photodynamic therapy as an adjunct to mechanical instrumentation in reducing counts of Enterococcus faecalis and Candida albicans from C-shaped root canals

BACKGROUND/PURPOSE

The aim was to assess the effectiveness of antimicrobial photodynamic therapy (aPDT) as an adjunct to mechanical instrumentation (MI) in reducing Enterococcus faecalis (E faecalis) and Candida albicans (C albicans) counts from C-shaped root-canals.

METHODS

Teeth with C-shaped canals as identified on cone beam computed tomographic images were included. Following incubation with E faecalis and C albicans, samples were divided into 4 groups a four follows: Group-1: MI with adjunct aPDT; Group-2: aPDT alone; Group-3: MI alone; and Group-4: no treatment. The pulp chambers of these teeth were exposed and coronal pulp was mechanically derided using sterile endodontic excavators. Using flexible files, all canals were debrided up to size #30 K-files with intermittent irrigation with 2.5% sodium hypochlorite irrigation. In Groups 1 and 3, methylene-blue was injected in all canals and aPDT was performed using a 600 nm diode laser. Sample-size estimation was done on data from a pilot investigation and group-comparisons were done using one way analysis of variance and Bonferroni post-hoc adjustment tests. P < .05 was considered statistically significant.

RESULTS

Sixty periodontally hopeless mandibular second molars with C-shaped canals were included. There was a statistically significant reduction CFU/mL of E faecalis (P < .001) and C albicans (P < .001). At post-operative microbial assessments in Group-1. There was no difference CFU/mL of E faecalis and C albicans at post-operative microbial assessments in Groups 2-4.

CONCLUSION

MI with adjunct aPDT is more effective in reducing count of E faecalis and C albicans from C-shaped root canals.

Inflammasomes in Alveolar Bone Loss

Bone remodeling is tightly controlled by osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Fine tuning of the osteoclast-osteoblast balance results in strict synchronization of bone resorption and formation, which maintains structural integrity and bone tissue homeostasis; in contrast, dysregulated bone remodeling may cause pathological osteolysis, in which inflammation plays a vital role in promoting bone destruction. The alveolar bone presents high turnover rate, complex associations with the tooth and periodontium, and susceptibility to oral pathogenic insults and mechanical stress, which enhance its complexity in host defense and bone remodeling. Alveolar bone loss is also involved in systemic bone destruction and is affected by medication or systemic pathological factors. Therefore, it is essential to investigate the osteoimmunological mechanisms involved in the dysregulation of alveolar bone remodeling. The inflammasome is a supramolecular protein complex assembled in response to pattern recognition receptors and damage-associated molecular patterns, leading to the maturation and secretion of pro-inflammatory cytokines and activation of inflammatory responses. Pyroptosis downstream of inflammasome activation also facilitates the clearance of intracellular pathogens and irritants. However, inadequate or excessive activity of the inflammasome may allow for persistent infection and infection spreading or uncontrolled destruction of the alveolar bone, as commonly observed in periodontitis, periapical periodontitis, peri-implantitis, orthodontic tooth movement, medication-related osteonecrosis of the jaw, nonsterile or sterile osteomyelitis of the jaw, and osteoporosis. In this review, we present a framework for understanding the role and mechanism of canonical and noncanonical inflammasomes in the pathogenesis and development of etiologically diverse diseases associated with alveolar bone loss. Inappropriate inflammasome activation may drive alveolar osteolysis by regulating cellular players, including osteoclasts, osteoblasts, osteocytes, periodontal ligament cells, macrophages, monocytes, neutrophils, and adaptive immune cells, such as T helper 17 cells, causing increased osteoclast activity, decreased osteoblast activity, and enhanced periodontium inflammation by creating a pro-inflammatory milieu in a context- and cell type-dependent manner. We also discuss promising therapeutic strategies targeting inappropriate inflammasome activity in the treatment of alveolar bone loss. Novel strategies for inhibiting inflammasome signaling may facilitate the development of versatile drugs that carefully balance the beneficial contributions of inflammasomes to host defense.

The Role of IL-17-Producing Cells in Cutaneous Fungal Infections

The skin is the outermost layer of the body and is exposed to many environmental stimuli, which cause various inflammatory immune responses in the skin. Among them, fungi are common microorganisms that colonize the skin and cause cutaneous fungal diseases such as candidiasis and dermatophytosis. The skin exerts inflammatory responses to eliminate these fungi through the cooperation of skin-component immune cells. IL-17 producing cells are representative immune cells that play a vital role in anti-fungal action in the skin by producing antimicrobial peptides and facilitating neutrophil infiltration. However, the actual impact of IL-17-producing cells in cutaneous fungal infections remains unclear. In this review, we focused on the role of IL-17-producing cells in a series of cutaneous fungal infections, the characteristics of skin infectious fungi, and the recognition of cell components that drive cutaneous immune cells.

Candida Albicans Virulence Factors and Its Pathogenicity

Candida albicans lives as commensal on the skin and mucosal surfaces of the genital, intestinal, vaginal, urinary, and oral tracts of 80% of healthy individuals [...].