Effectiveness of intracanal irrigants and medications against the yeast Candida albicans

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.

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.

Assessing Efficacy of Clinical Disinfectants for Pathogenic Fungi by Single-Cell Raman Microspectroscopy

Disinfectants are crucial for root canal therapy (RCT), as metabolism of canal-inhabiting microbes can cause refractory infections. To develop effective yet patient- and environment-friendly disinfectant formulations, we quantitatively assessed the metabolism-inhibiting effects of intracanal disinfectants via D₂O-probed Single-Cell Raman Spectra (SCRS), using Candida albicans (C. albicans) as a pathogen model. For chlorhexidine gluconate (CHX), sodium hypochlorite (NaClO), and hydrogen peroxide (H₂O₂), at their MIC of 4, 168, and 60 μg/ml, respectively, despite the complete growth halt, metabolic activity of individual fungal cells was reduced on average by 0.4%, 93.9%, and 94.1% at 8 h, revealing a “nongrowing but metabolically active” (NGMA) state that may underlie potential refractory infections, particularly for CHX. In contrast, at their Metabolic Activity-based Minimum Inhibitory Concentrations (MIC-MA) of 8, 336, and 120 μg/ml, respectively, metabolic activity of all cells was completely halted throughout 8 h exposure. Moreover, combined use of NaClO+H₂O₂ (combination at 0.5× MIC-MA each) outperforms solo uses of CHX, NaClO, H₂O₂, or other binary combinations. Furthermore, dynamics of SCRS revealed distinct fungicidal mechanisms of CHX, NaClO, H₂O₂, and their pairwise combinations. MIC-MA is advantageous in critically assessing antifungal efficacy, and NaClO+H₂O₂ can potentially serve as a more efficient disinfectant formula for fungal pathogens.

Comparing the Antifungal Effect of Sodium Hypochlorite Gel versus Different Types of Root Canal Medicaments at Different Time Intervals Using the Agar Diffusion Test: An In Vitro Study

Aims

The purpose of this study was to compare the antifungal activity of sodium hypochlorite gel to those of four intracanal medicaments at various time intervals.

Materials and Methods

The agar well diffusion technique was utilized to test the antifungal activity of the following medicaments against Candida albinans (C. albicans): sodium hypochlorite gel, chlorhexidine gel, calcium hydroxide paste, Ledermix, and Diapex Plus. The inhibition zone related to each medicine was measured in millimeter after 24, 48, and 72 hours of incubation at 37°C. The data were analyzed using one-way ANOVA and Games–Howell tests, at a significance level of P < 0.05.

Results

Except for Ledermix and Diapex Plus, which had no antifungal action, all of the medicaments showed varied inhibitory zones for C. albicans. At all periods, the NaOCl gel had the most significant inhibition zones, followed by the CHX gel and calcium hydroxide. At all time intervals, the NaOCl gel demonstrated comparable antifungal efficacy. When compared to a 24-hour time interval, the CHX gel showed an increased antifungal activity at the 48-hour and 72-hour intervals. Calcium hydroxide, on the other hand, showed a decrease in its antifungal activity at the 72-hour interval.

Conclusion

The antifungal activity of sodium hypochlorite gel was the highest among the investigated medicaments. Chlorhexidine gel's antifungal activity improved over time, whereas calcium hydroxide's antifungal activity declined. Diapex Plus and Ledermix did not have any antifungal properties.

Antibacterial, biological, and physicochemical properties of root canal sealers containing chlorhexidine-hexametaphosphate nanoparticles

OBJECTIVE

The aim of this study was to evaluate the influence of the incorporation of chlorhexidine-hexametaphosphate nanoparticles (CHX-HMP NPs) on antibacterial, cytotoxic and physicochemical properties of AH Plus (AH), MTA Fillapex (MTA) and Pulp Canal Sealer (PCS).

METHODS

The NPs were synthesized and characterized by Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), zeta potential, Atomic Force Microscopy (AFM) and Energy-Dispersive X-ray Spectroscopy (EDS). The incorporation was made by weight, 2% and 5% of NPs. The antimicrobial activity, cytotoxicity, flow, radiopacity, setting time, solubility and pH were evaluated. The statistical analysis was performed by two-way analysis of variance test and Tukey post hoc test (P < 0.05).

RESULTS

SEM analysis showed the tendency for CHX-HMP NPs to cluster, the effective mean diameter measured by DLS: 169.39 nm and the zeta potential: -10.18 mV. The NPs were individually measured by AFM: 22.99-52.75 nm. EDS analysis identified the presence of C, N, O, Na, P, Cl. After incorporation: The Direct Contact Test showed an increase in the antimicrobial action of AH, PCS and MTA; the sealers showed a decrease in flow and at 24 h of immersion also an increase in solubility, but did not affect the radiopacity of the samples; AH setting time increased and MTA did not reach setting under any of the conditions tested. All samples showed a decrease in pH value as the immersion time progressed.

SIGNIFICANCE

The incorporation of NPs can improve the antimicrobial performance of endodontic sealers without impairing other biological and physicochemical properties.

Antifungal and Synergistic Effects of the Ethyl Acetate Extract of Tanacetum vulgare (L.) Against Candida albicans

BACKGROUND With the continued demand for new, effective, and safe endodontic therapies, the aim of this study was assessment of efficiency of the ethyl acetate (EthOAc) extract of Tanacetum vulgare (L.) against Candida albicans. MATERIAL AND METHODS The antifungal effectiveness of the EthOAc extract of T. vulgare was determined using the agar disk diffusion method. The inhibition zones induced by the EthOAc extract were compared after 5 minutes, 60 minutes, and 24 hours to those induced by standard solutions (2% chlorhexidine, saturated calcium hydroxide, and 2% sodium hypochlorite). Statistical analysis of the results was performed using the Kruskal-Wallis test and one-way ANOVA. RESULTS The inhibition zone of chlorhexidine against C. albicans was 30.3-19.3 mm, but in combination with EthOAc extract (100 mg/mL) of T. vulgare, this inhibition was from 32.7-30 mm, indicating that this combination exerted a marked synergistic effect against C. albicans. The inhibition zone of sodium hypochlorite (69.7-65 mm) was higher than the inhibition zone of EthOAc extract and chlorhexidine. The combination of EthOAc extract with sodium hypochlorite resulted in a loss of antifungal activity. Furthermore, the activity of the EthOAc extract against C. albicans was decreased after mixing the extract with dentine at a concentration of 25 mg/50 µL (30.3-20.7 mm). The EthOAc extract did not show a genotoxic effect on lymphocyte cells. CONCLUSIONS The EthOAc extract of T. vulgare may be a useful tool to discover natural bioactive agents that have antifungal activity against C. albicans and could be used as endodontic therapies.

Exploring the role of Morinda citrifolia and Triphala juice in root canal irrigation: An ex vivo study

Background:

The present ex vivo study explores the role of Indian medicaments in endodontic irrigation in an attempt to search for a safe alternative to sodium hypochlorite (NaOCL).

Aim:

To evaluate the efficacy of commercial preparations of Morinda citrifolia juice (MCJ) and Triphala juice against Enterococcus faecalis and Candida albicans.

Materials and Methods:

The study was conducted on 84 permanent extracted human teeth. After decoronation and biomechanical preparation, inoculated (with E. faecalis and C. albicans) root sections were divided randomly into four experimental (MCJ, Triphala juice, 1% NaOCl, and 2% chlorhexidine [CHX]) and two control groups (preservative control and distilled water). Colony-forming units (CFUs) obtained for each group were counted at baseline (S₀) and after irrigation at 1 and 3 days (S₁and S₂, respectively). Mean of Log CFU at S₀, S₁, and S₂was compared for each irrigant using Friedman's two-way ANOVA.

Results:

There was a significant decrease in microbial counts of both microbes in all groups at S₁, but only CHX could demonstrate further decrease in the microbial counts of both microorganisms at S₂.

Conclusion:

The overall antimicrobial effects of different irrigants were maximum for CHX, whereas MCJ and Triphala juice also showed significant reductions. The herbal irrigants hold the promise of becoming efficient irrigants and warrant further research.

Antifungal Effects of Synthetic Human Beta-defensin-3-C15 Peptide on Candida albicans-infected Root Dentin

INTRODUCTION

The aim of this study was to assess the antifungal efficacy of a synthetic human beta-defensin-3-C15 peptide (HBD3-C15) in Candida albicans-infected human root dentin.

METHODS

Standardized root dentin blocks were prepared (6-mm thick, 0.7-mm-wide canal) from single-rooted human permanent premolars and infected with C. albicans for 3 weeks. They were randomly divided into 4 groups (n = 8/group), and their canals were filled with calcium hydroxide (CH), HBD3-C15 peptide, or chlorhexidine digluconate (CHX, 2%) as disinfectants or saline as control. After 1 week of disinfection, dentinal debris were harvested at depths of 200 and 400 μm from the canal lumen, and incubated in Yeast broth for 72 hours at 37°C. Then, colony-forming units (CFU) were measured to assess the antifungal efficacy of each medicament and analyzed statistically.

RESULTS

All medicaments showed significantly lower CFU than saline (P < .05), and their antifungal efficacies were similar at both 200- and 400-μm tubular depths (P > .05). HBD3-C15 had similar antifungal efficacy to that of CHX at both depths (P > .05), and both medicaments had significantly lower CFU than CH at both depths (P < .05).

CONCLUSIONS

In this ex vivo model of C. albicans-infected human root dentin, the antifungal efficacy of synthetic HBD3-C15 was comparable with CHX.

Effects of photodynamic therapy, 2 % chlorhexidine, triantibiotic mixture, propolis and ozone on root canals experimentally infected with Enterococcus faecalis: an in vitro study

The aim of this study was to evaluate the antibacterial effect of photodynamic therapy (PDT), 2 % chlorhexidine (CHX). The teeth were contaminated with 0.1 mL Enterococcus faecalis (3 × 10⁸ cell/mL) and randomized into eight treatment groups: Group 1 (2.5 % NaOCl); Group 2 (PDT); Group 3 (2 % CHX); Group 4 (TAM); Group 5 (propolis), Group 6 (ozone), Group 7 (positive control) and Group 8 (negative control). Following treatment, the canal content was sampled. The samples were cultured in triplicate on blood agar plates to determine the number of colony forming units (CFU)/mL. The teeth were analyzed by SEM to determine the percentage of area with contamination and debris. The group with the lowest CFU/mL count was the ozone group, which obtained similar values to the PDT group. SEM images showed that 2.5 % NaOCL group showed the lowest percentage of contaminated area. Applications of PDT, 2 % CHX, TAM, propolis and ozone showed antibacterial potential similar to 2.5 % NaOCL.

[Efficacy of sodium hydroxide at 2.5 %, chlorhexidine gluconate at 0.5 % and calcium hydroxide against Candida albicans]

INTRODUCTION

Endodontic flora is dominated in the apical part of the channels by strict anaerobic and some facultative anaerobic bacteria but also by Candida yeasts, especially Candida albicans species that are involved in the maintenance and persistence of endodontic infections. Their elimination of the canal system in practice by chemo-mechanical methods of disinfection is not always guaranteed. Thus, this in vitro study was performed to determine the sensitivity of C. albicans with sodium hypochlorite (NaOCl) dosed at 2.5 %, the chlorhexidine digluconate 0.5 % and calcium hydroxide used in inter-session medication.

METHODS

The diffusion method was used initially to test the sensitivity of C. albicans strains with the above products. Then a dilution technique has allowed us to determine the minimum inhibitory concentration of these active products on C. albicans.

RESULTS

Strains from infected pulp teeth of patients showed a sensitivity of C. albicans to sodium hypochlorite to a minimum inhibitory concentration less than 70μg/mL and 30μg/mL for chlorhexidine.

CONCLUSION

This study demonstrated a sensitivity of C. albicans to sodium hypochlorite and chlorhexidine.

Antimicrobial efficacy of chlorhexidine as a root canal irrigant: a literature review

Use of an appropriate root canal irrigant is essential during endodontic treatment, due to the complex and unpredictable anatomy of the root canal system and limitations in the mechanical instrumentation techniques used to obtain a clean, bacteria-free canal. Several irrigants, such as sodium hypochlorite, chlorhexidine, hydrogen peroxide, and normal saline, have been proposed as canal system irrigants in endodontic treatment. The widely used endodontic irrigant chlorhexidine is a positively charged lipophilic/hydrophobic molecule that interacts with phospholipids and lipopolysaccharides on the bacterial cell membrane. In endodontics, its mode of antibacterial activity is determined by its concentration (0.2% or 2%). This article reviews findings from available endodontic studies on the antibacterial, antifungal, and antibiofilm activities of chlorhexidine.

Vitamin B2-sensitized degradation of the multifunctional drug Evernyl, in the presence of visible light – microbiological implications

Taking into consideration the importance of the photooxidative effects in complex bio- environments, this paper reports on the visible-light-promoted interactions between Evernyl (methyl 2, 4-dihydroxy-3,6-dimethylbenzoate, Ev) and vitamin B2 (riboflavin, Rf). Ev is a phenolic derivative, transparent to visible light, that possesses important antimicrobial activity. This compound is the first known natural, complete and specific human androgen receptor antagonist. Ev is profusely employed in personal-care products and synthesized as a secondary metabolite by several lichen and plant species. In both sceneries, acting Ev as a cosmetic component for topic applications or as a lichen constituent, may Rf behave as a native visible-light absorber pigment. In this context, kinetic and mechanistic aspects of the Rf-sensitized photooxidation of Ev, has been studied in aqueous solution, irradiating with blue LED light (463–471 nm) and employing stationary and time resolved methods. Results indicate that Ev reacts with the photogenerated reactive oxygen species (ROS) singlet molecular oxygen with a rate constant of kr=1.1±0.2×106 M−1s−1. In parallel Ev also quenches the electronically excited singlet and triplet excited states of Rf with rate constants close to the difussion limit. As a result the ROS superoxide radical anion and hydrogen peroxide are generated and the latter subsequently reacts with Ev. Possible implications of these photoreactions on the antimicrobial activity of Ev have been investigated employing a Candida albicans (CA) strain, isolated from human skin infection. The simultaneous presence of Rf, Ev in a sub-MIC, and blue-light irradiation produced a significant antimycotic effect, attributed to ROS photogeneration.

Evaluation of antifungal activity of white-colored mineral trioxide aggregate on different strains of Candida albicans in vitro

AIM

The purpose of this study was to evaluate the antifungal action of various concentrations of white mineral trioxide aggregate (MTA) against seven different strains of Candida albicans using the tube dilution test.

MATERIALS AND METHODS

Fresh mix of MTA was prepared at concentrations of 100, 50, 25, and 12.5 mg/ml and added to a broth tube containing Sabouraud's liquid medium. A total of 1287 broth tubes were prepared and divided into experimental and control groups. Stock cultures of seven strains of C. albicans were obtained. Fresh inoculate of the microorganism was prepared by growing overnight cultures. Aliquots of the test C. albicans were taken and added to the test tubes. All tubes were incubated at 37°C for 1-, 24-, 72-, and 168-h time periods. At each time period, the presence of C. albicans colonies was assessed.

STATISTICAL ANALYSIS USED

Differences among the groups were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

Results showed that one strain showed resistance even after 3 days at the lower MTA concentrations of 12.5 and 25 mg/ml. Growth reoccurred with three strains at MTA concentration of 12.5 mg/ml after 7 days. A significant difference was found between strain 3 and other strains at MTA concentrations of 12.5 and 25 mg/ml at the 3-days time period and between tubes containing 12.5 mg/ml and tubes containing higher concentrations of MTA at the 7-days time period.

CONCLUSION

White MTA in concentrations of 100 and 50 mg/ml is effective in inhibiting the seven tested strains of C. albicans for periods up to 1 week.

In vitro-activity of oily calcium hydroxide suspension on microorganisms as well as on human alveolar osteoblasts and periodontal ligament fibroblasts

Background

Findings from animal and human studies have indicated that an oily calcium hydroxide suspension (OCHS) may improve early wound healing in the treatment of periodontitis. Calcium hydroxide as the main component is well known for its antimicrobial activity, however at present the effect of OCHS on the influence of periodontal wound healing/regeneration is still very limited. The purpose of this in vitro study was to investigate the effect of OCHS on periodontopathogenic bacteria as well as on the attachment and proliferation of osteoblasts and periodontal ligament fibroblasts.

Methods

Human alveolar osteoblasts (HAO) and periodontal ligament (PDL) fibroblasts were cultured on 3 concentrations of OCHS (2.5, 5 and 7.5 mg). Adhesion and proliferation were counted up to 48 h and mineralization was assayed after 1 and 2 weeks. Furthermore potential growth inhibitory activity on microorganisms associated with periodontal disease (e.g. Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans) as well as the influence of periodontopathogens and OCHS on the HAO and PDL fibroblasts counts were determined.

Results

More than a 2-fold increase in adherent HAO cells was observed at 4 h following application of OCHS when compared to the control group (p = 0.007 for 2.5 mg). Proliferation of HAO cells at 48 h was stimulated by moderate concentrations (2.5 mg; 5 mg) of OCHS (each p < 0.001), whereas a high concentration (7.5 mg) of OCHS was inhibitory (p = 0.009). Mineralization was observed only for HAO cells treated with OCHS. OCHS did not exert any positive effect on attachment or proliferation of PDL fibroblasts. Although OCHS did not have an antibacterial effect, it did positively influence attachment and proliferation of HAO cells and PDL fibroblasts in the presence of periodontopathogens.

Conclusions

The present data suggests that OCHS promotes osteoblast attachment, proliferation and mineralization in a concentration-dependent manner and results are maintained in the presence of periodontal pathogens.

Chlorhexidine in Endodontics

Chemical auxiliary substances (CAS) are essential for a successful disinfection and cleanness of the root canals, being used during the instrumentation and if necessary, as antimicrobial intracanal medicaments. Different CAS have been proposed and used, among which sodium hypochlorite (NaOCl), chlorhexidine (CHX), 17% EDTA, citric acid, MTAD and 37% phosphoric acid solution. CHX has been used in Endodontics as an irrigating substance or intracanal medicament, as it possesses a wide range of antimicrobial activity, substantivity (residual antimicrobial activity), lower cytotoxicity than NaOCl whilst demonstrating efficient clinical performance, lubricating properties, rheological action (present in the gel presentation, keeping the debris in suspension); it inhibits metalloproteinase, is chemically stable, does not stain cloths, it is odorless, water soluble, among other properties. CHX has been recommended as an alternative to NaOCl, especially in cases of open apex, root resorption, foramen enlargement and root perforation, due to its biocompatibility, or in cases of allergy related to bleaching solutions. The aim of this paper is to review CHX's general use in the medical field and in dentistry; its chemical structure, presentation form and storage; mechanism of action; antimicrobial activity including substantivity, effects on biofilms and endotoxins, effects on coronal and apical microbial microleakage; tissue dissolution ability; interaction with endodontic irrigants; effects on dentin bonding, metalloproteinases and collagen fibrils; its use as intracanal medicament and diffusion into the dentinal tubules; its use as disinfectant agent of obturation cones; other uses in the endodontic therapy; and possible adverse effects, cytotoxicity and genotoxicity.

Antimicrobial activity of calcium hydroxide in endodontics: a review

The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

Comparative evaluation of effectiveness of sodium dichloroisocyanurate and calcium hydroxide against Candida albicans

INTRODUCTION

Candida albicans is the most commonly isolated fungi from the oral cavity. It is the most infective to various intracanal medicaments and is considered as invasive yeast. Sodium dichloroisocyanurate (NaDCC) which is used as a disinfectant and as a biocide in treating potable water has similar action to that of sodium hypochlorite against microbes. The aim of the present study is to compare the effectiveness of calcium hydroxide and NaDCC against Candida albicans.

MATERIALS AND METHODS

After obtaining the stock cultures of Candida, the isolates were divided into six groups which were exposed to different concentrations of NaDCC and calcium hydroxide Ca(OH)₂. Group 1 consisted of the isolates which were subdivided into three groups, subjected to three different concentrations of NaDCC. Group 2 also consisted of three subgroups exposed to three different concentrations of Ca(OH)₂. Group three consisted of three subgroups which were exposed to three different concentrations of combinations of both NaDCC and Ca(OH)₂.

RESULTS

The results of the present study show that calcium hydroxide was totally ineffective at all concentrations and NaDCC was effective and also the combination of both was shown to be effective.

CONCLUSION

NaDCC alone was effective at all concentrations and the combination with Ca(OH)₂ was found to be less effective. Ca(OH)₂ was totally ineffective.

In vitro susceptibility of oral Candida albicans strains to different pH levels and calcium hydroxide saturated aqueous solution

Candida albicans is present in the oral cavity and in the whole digestive tract of humans and other animals, being frequently related to endodontic treatment failure. The present study determined the incidence of C. albicans in the oral cavity and the susceptibility of isolates to different pH values and saturated calcium hydroxide aqueous solution at pH 12.5. Sixty-five patients attending the Endodontic Clinic at the Sagrado Coração University participated in the study. The collected samples were cultivated in selective media for C. albicans and the isolates were tested in terms of resistance to both alkaline pH and saturated aqueous solution of calcium hydroxide. In relation to time variables, yeast viability was assessed by the Sabouraud's agar culture and fluorescein diacetate and ethidium bromide fluorescent staining method. Results from the different pHs and experimental times, including those from different techniques measuring fungal viability, were compared using the chi-square and Fisher's exact tests (α=0.05). The yeasts became completely inviable after 48 h of contact with the calcium hydroxide solution. On the other hand, when exposed to the alkaline culture broth, the yeasts were found to be viable at pHs 9.5 and 10.5 for up to 7 days. In conclusion, C. albicans can only be completely inhibited by direct contact with saturated calcium hydroxide aqueous solution after 48 h of exposure.

Properties and applications of calcium hydroxide in endodontics and dental traumatology

Calcium hydroxide has been included within several materials and antimicrobial formulations that are used in a number of treatment modalities in endodontics. These include, inter-appointment intracanal medicaments, pulp-capping agents and root canal sealers. Calcium hydroxide formulations are also used during treatment of root perforations, root fractures and root resorption and have a role in dental traumatology, for example, following tooth avulsion and luxation injuries. The purpose of this paper is to review the properties and clinical applications of calcium hydroxide in endodontics and dental traumatology including its antibacterial activity, antifungal activity, effect on bacterial biofilms, the synergism between calcium hydroxide and other agents, its effects on the properties of dentine, the diffusion of hydroxyl ions through dentine and its toxicity. Pure calcium hydroxide paste has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. Its main actions are achieved through the ionic dissociation of Ca(2+) and OH(-) ions and their effect on vital tissues, the induction of hard-tissue deposition and the antibacterial properties. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. It has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also an effective anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

Evaluation of antifungal efficacy of erbium, chromium: yttrium-scandium-gallium-garnet laser against Candida albicans

OBJECTIVE

The purpose of this in vitro study was to investigate the ability of Er,Cr:YSGG laser irradiation at different energy settings to eliminate Candida albicans, either with or without 5.25% sodium hypochlorite (NaOCl) treatment.

METHODS

In total, 90 extracted human single-rooted teeth were shaped by using a crown-down technique with HERO Shaper rotary instruments and irrigated with 1 mL of 2.5% NaOCl between each instrument. The specimens were autoclaved and incubated with a suspension of C. albicans (ATCC 90028). Then the specimens were divided into six treatment groups (n = 15 per group): group 1, NaOCl + 1-W laser; group 2, 1-W laser; group 3, NaOCl + 0.75-W laser; group 4, 0.75-W laser, group 5, NaOCl; and group 6, no treatment. Aliquots of the experimental teeth were transferred onto Sabouraud's dextrose agar plates with paper points, and colony-forming units (CFUs) were counted as a measure of antifungal activity. One root from each group, which was not submitted to the sampling procedure, was fixed in glutaraldehyde, split into two halves, and evaluated with scanning electron microscopy (SEM). Statistical analysis was performed by using analysis of variance (ANOVA) and the Dunnett t test. Significance was set at alpha = 0.05.

RESULTS

All the treatment groups resulted in a significant reduction of C. albicans, but no sterilization, and all the groups were significantly different from each other (p < 0.0001). Group 1 (NaOCl and 1-W laser combination) exhibited the greatest reduction, whereas group 5 (NaOCl) resulted in a minimal reduction in CFUs of C. albicans. The SEM observations were in accordance with the microbiologic analysis.

CONCLUSIONS

The 5.25% NaOCl and 1-W laser treatment combination may be a valuable cleaning tool for root canals infected with C. albicans.

Chlorhexidine gluconate in endodontics: an update review

The major objective in root canal therapy is to disinfect the entire root canal system. This requires that the pulpal contents be eliminated as sources of infection. This goal may be accomplished using mechanical instrumentation and chemical irrigation, in conjunction with medication of the root canal between treatment sessions. Microorganisms and their by-products are considered to be the major cause of pulpal and periradicular pathosis. In order to reduce or eliminate bacteria, various irrigation solutions have been used during treatment. Chlorhexidine is a cationic molecule which can be used during treatment. It has a wide range antimicrobial activity. Furthermore, because of its cationic structure, chlorhexidine has a unique property named substantivity. The purpose of this paper is to review different aspects of the use of chlorhexidine gluconate in endodontics.

Antimicrobial effect, in vitro, of gutta-percha points containing root canal medications against yeasts and Enterococcus faecalis

OBJECTIVE

The objective of this study was to determine the in vitro susceptibility of Enterococcus faecalis and the most prevalent Candida species as therapy-resistant microorganisms to gutta-percha points containing root canal medications.

STUDY DESIGN

Gutta-percha points containing calcium hydroxide (Calcium Hydroxide Plus Points), chlorhexidine diacetate (Activ Points), or calcium hydroxide-chlorhexidine combinations (CHX/Ca Combi Points) were tested for their ability to inhibit growth of pure cultures of Candida albicans, Candida glabrata, Candida parapsilosis, Candida krusei, Candida tropicalis, Saccharomyces cerevisiae, and Enterococcus faecalis. Approximately 2 x 10(7) microorganisms per assay were suspended in diluted human serum and co-incubated with the gutta-percha points placed in Eppendorf tubes in an incubator for up to 2 weeks. A tube was removed at 1, 2, 3, 4, 7, and 14 days, and then opened and microorganism suspensions were serially diluted in a sterile 0.9% NaCl solution. Aliquots of the dilution steps were streaked onto solid medium. After incubating the plates in an incubator at 37 +/- 1 degrees C for 48 hours, CFU numbers per milliliter of suspension were calculated.

RESULTS

Calcium Hydroxide Plus Points or Activ Points did not exhibit sufficient antimicrobial or anticandidal activity for Enterococcus faecalis, Candida albicans, C. glabrata, C. parapsilosis, C. krusei, or C. tropicalis within 14 days. Only Saccharomyces cerevisiae was susceptible to the calcium hydroxide or chlorhexidine diacetate containing gutta percha points. CHX/Ca Combi Points killed C. albicans, C. glabrata, C. krusei, C. tropicalis, and S. cerevisiae completely. However, E. faecalis and C. parapsilosis were resistant to CHX/Ca Combi points within 14 days.

CONCLUSION

The results show the gutta percha points containing a mixture of calcium hydroxide and chlorhexidine diacetate have efficacies superior to calcium hydroxide or chlorhexidine diacetate alone against some microorganisms except E. faecalis and C. parapsilosis.

In vitro assessment of the effectiveness of chlorhexidine gel and calcium hydroxide paste with chlorhexidine against Enterococcus faecalis and Candida albicans

OBJECTIVE

The purpose of this study was to compare the effectiveness of various medicaments, including Ca(OH)2/2% chlorhexidine, 2% chlorhexidine gel, and Ca(OH)2 alone, against Enterococcus faecalis and Candid albicans in vitro.

STUDY DESIGN

Eighty extracted single-rooted human maxillary teeth were used. After removing the crown, each root was instrumented up to size 50 by using a conventional technique. The root canal was irrigated with ethylenediamine tetra-acetic acid (EDTA) solution to remove smear layer. Then, roots were infected with E faecalis and C albicans. Subsequently, the roots were divided into 4 treatment groups: group 1 was treated with calcium powder hydroxide in distilled water, group 2 was treated with calcium hydroxide powder in 2% chlorhexidine, group 3 was treated with 2% chlorhexidine gel, and group 4 was treated with 0.9% sterile saline serving as negative control. Microbial samples were taken after 7, 15, and 30 days. After incubation, dentine chips were obtained form each root canal and examined microbiologically. The microbiological samples were plated to count colony-forming units in per milligram of dentin.

RESULTS

The results showed that the 2% chlorhexidine gel was significantly more effective than calcium hydroxide with 2% chlorhexidine, calcium hydroxide, and control saline solution (P < .05).

CONCLUSION

Under the conditions of this study, 2% chlorhexidine gel is effective in the elimination of E faecalis and C albicans from the root canal system. However, to support this in vitro observation, further in vivo studies are needed.

The effect of calcium chelating or binding agents on Candida albicans

OBJECTIVE

The aim of this study was to evaluate antifungal effects of calcium-chelating or -binding agents on Candida albicans comparing with conventional antifungal agents.

STUDY DESIGN

Two clinical oral isolates and 1 standard strain of C albicans were included in the study. Test solutions were ethylenediamine-tetraacetic acid (EDTA), ethyleneglycol-tetraacetic acid (EGTA), sodium fluoride (NaF), titanium tetrafluoride (TiF4), nystatin, and ketoconazole. Minimum inhibitory and fungicidal concentrations of the solutions were determined. The results were analyzed statistically using Friedman's nonparametric 2-way ANOVA and Mann-Whitney U tests.

RESULTS

All isolates demonstrated similar susceptibility patterns (P>.05). Except ketoconazole, EDTA had the highest antifungal and fungicidal activity, followed by TiF4. EGTA and NaF were the weakest agents against C albicans among all test solutions.

CONCLUSION

EDTA and TiF4 may be recommended as an alternative irrigating solution particularly in persistent root canal infections and in root canals of patients having a high incidence of oral candidosis.

Effect of White-Colored Mineral Trioxide Aggregate in Different Concentrations on Candida albicans In Vitro

The antifungal action of different concentrations of white-colored mineral trioxide aggregate (MTA) against Candida albicans was assessed in vitro. Fresh mix of MTA was prepared at concentrations varying from 0.78 mg/ml to 50 mg/ml by dilution with 10 ml molten agar at 45 degrees C. The MTA-agar compound was thoroughly mixed and the uniform mix was then poured into sterile Petri dishes and allowed to set. A total of 348 agar plates were prepared and divided into experimental groups of 11 plates each and control groups of 5 plates each. Plates of agar without MTA served as positive control and plates without C. albicans served as negative control. Fresh inoculate of C. albicans was prepared by growing an overnight culture from a stock culture. Aliquots of C. albicans were then taken from the stock culture and plated on the agar compound of the experimental and positive control groups. All plates were incubated at 37 degrees C for 1, 24, 48, and 72-h periods. At each time period, the presence of C. albicans colonies was assessed and recorded. A direct correlation was found between MTA concentration and its inhibition effect on C. albicans growth. Plates containing MTA in concentration of 50 mg/ml showed significantly better killing action against C. albicans in all of the time periods tested (p < 0.001). Plates containing MTA in concentration of 25 mg/ml showed antifungal activity only at 1 and 24-h time periods. Plates containing lower concentrations of MTA did not show any antifungal activity. It appears that under the conditions of this study, white-colored MTA in concentration of 50 mg/ml is effective in killing C. albicans for periods of up to 3 days. Lower MTA concentrations may not be effective.

Susceptibility of some oral microorganisms to chlorhexidine and paramonochlorophenol

Since the use of antimicrobial agents is required in endodontic therapies, this study aimed at determining the minimum inhibitory concentrations (MICs) of chlorhexidine digluconate and paramonochlorophenol (PMC) against microorganisms commonly found in endodontic infections. Both agents were tested by agar dilution tests against Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Candida albicans, Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella denticola and Prevotella melaninogenica. The MIC of chlorhexidine ranged from 2.67 to 80.00 µg/ml, and the MIC of PMC from 46.67 to 213.33 µg/ml. The highest MIC value of PMC was detected for E. faecalis whereas E. coli was the most susceptible microorganism to this agent. The highest MIC values of chlorhexidine were observed for P. aeruginosa whereas E. coli and P. denticola were the most susceptible microorganisms to this agent. Since the MIC values observed are much lower than the concentrations currently used in the endodontic therapy, it is suggested that both agents are effective in reducing the microbiota in the root canal.

In vitro evaluation of the effectiveness of irrigants and intracanal medicaments on microorganisms within root canals

AIM

To evaluate in vitro the effectiveness of sodium hypochlorite (NaOCl), chlorhexidine (CHX) and five intracanal medicaments on microorganisms within root canals.

METHODOLOGY

Ninety-six human single-rooted extracted teeth were used. After removing the crowns, canal preparation was completed and the external root surfaces were coated with epoxy resin. Following sterilization, the teeth were contaminated with Candida albicans and Enterococcus faecalis, and were incubated at 37 +/- 1 degrees C for 7 days. The teeth were divided according to the irrigant solution or intracanal medicament: group 1, sterile physiologic solution (SPS) and calcium hydroxide (Ca(OH)2) paste; group 2, SPS and camphorated paramonochlorophenol (CPMC); group 3, SPS and tricresol formalin; group 4, SPS and CaOH2 + CPMC paste; group 5, SPS and PMC furacin; group 6, 2.5% NaOCl without intracanal medication; group 7, 2.0% CHX without intracanal medication and group 8, SPS without intracanal medication (control group). Microbiological samples were collected with sterile paper points, and bacterial growth was determined. The data were submitted to the analysis of variance (anova, P = 0.05).

RESULTS

For C. albicans, groups 3 and 8 were statistically less effective than groups 1, 2, 4 and 5 (Kruskal-Wallis (K-W) = 65.241; gl = 7; P = 0.001). For E. faecalis, groups 6 and 8 were statistically less effective than groups 1-4 and 7 (K-W = 61.048; gl = 7; P = 0.001).

CONCLUSIONS

Ca(OH)2 + CPMC paste was the most effective intracanal medicament for the elimination of the two microorganisms; 2.0% CHX solution was more effective than 2.5% NaOCl against E. faecalis.