The Antifungal Effect of Propolis Endodontic Irrigant with Three Other Irrigation Solutions in Presence and Absence of Smear Layer: An In Vitro Study

Decrease from main root canal and intratubular Fusobacterium nucleatum and its endotoxin after ultrasonic activation of conventional and alternative irrigation solutions

This study evaluated conventional and alternative irrigation solutions combined with ultrasonic irrigant activation (UIA) against Fusobacterium nucleatum (F. nucleatum) and its endotoxin (LPS) in main root canal and dentinal tubules, using a new intratubular infection model. Seventy dentin cylinders were infected with F. nucleatum for seven days under anaerobic conditions and treated with 2.5% sodium hypochlorite (NaOCl), limewater + 2.5% NaOCl, and 10% ethanolic propolis extract (EEP), administered by syringe irrigation (SI) or UIA. Microbiological samples were collected before and after irrigation to determine CFU ml-1 and LPS levels. Confocal microscopy assessed bacterial membrane damage with Live/Dead staining. Irrigation solutions effectively reduced CFU ml-1. UIA caused greater damage to the bacterial membranes and reduced LPS levels. The ultrasonic activation of 10% EEP and limewater + 2.5% NaOCl were comparable to 2.5% NaOCl (p > 0.05). UIA improved the effectiveness of solutions, suggesting potential for alternative substances. Randomized clinical trials using these protocols are recommended.

Comparative Evaluation of Smear Layer Removal Efficacy of Neem Leaf Extract, Propolis, and Orange Oil when used as Endodontic Irrigants: An in vitro Scanning Electron Microscopic Study

Introduction

In root canal treatment, chemical debridement of the root canal with the help of irrigants is important due to the complex internal anatomy of the teeth. Biomechanical root canal preparation produces a smear layer. It covers the dentinal tubules, which may interfere with the penetration of various irrigants and intracanal medicaments, so the smear layer has to be removed. The potential side effects and certain limitations of chemical irrigants for smear layer removal have led to a shift toward herbal alternatives.

Objective

The aim of the present study was to evaluate and compare the smear layer removal efficacy of Neem leaf extract, Propolis, and Orange oil as endodontic irrigants using the scanning electron microscope.

Materials and Methods

Ninety samples were taken and then randomly (simple random sampling method) divided into three experimental groups (n = 30) depending upon different endodontic irrigants used: Group 1-Neem leaf extract, Group 2-Orange oil and Group 3-Propolis and smear layer removal evaluation was done under the scanning electron microscope Scanning Electron Microscope (SEM) at all the levels, i.e., coronal, middle, and apical.

Results

The collected data were analyzed using the Chi-square test. Group 1 (Neem leaf extract) showed the highest smear layer removal efficacy, which was followed by Group 2 (Orange oil) and the least efficacy of smear layer removal was shown by Group 3 (Propolis) at coronal, middle, and apical levels.

Conclusion

Group 1 (Neem leaf extract) performed significantly better in removing the smear layer at coronal, middle, and apical levels as compared to the other two groups.

Antibiofilm Potential of Medicinal Plants against Candida spp. Oral Biofilms: A Review

The use of natural products to promote health is as old as human civilization. In recent years, the perception of natural products derived from plants as abundant sources of biologically active compounds has driven their exploitation towards the search for new chemical products that can lead to further pharmaceutical formulations. Candida fungi, being opportunistic pathogens, increase their virulence by acquiring resistance to conventional antimicrobials, triggering diseases, especially in immunosuppressed hosts. They are also pointed to as the main pathogens responsible for most fungal infections of the oral cavity. This increased resistance to conventional synthetic antimicrobials has driven the search for new molecules present in plant extracts, which have been widely explored as alternative agents in the prevention and treatment of infections. This review aims to provide a critical view and scope of the in vitro antimicrobial and antibiofilm activity of several medicinal plants, revealing species with inhibition/reduction effects on the biofilm formed by Candida spp. in the oral cavity. The most promising plant extracts in fighting oral biofilm, given their high capacity to reduce it to low concentrations were the essential oils extracted from Allium sativum L., Cinnamomum zeylanicum Blume. and Cymbopogon citratus (DC) Stapf.

Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal

To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I-saline; group II-propolis 100 µg/mL; group III-propolis 300 µg/mL; group IV-propolis nanoparticle 100 µg/mL; group V-propolis nanoparticle 300µg/mL; group VI-6% sodium hypochlorite; group VII-2% chlorhexidine. Dentin shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and β-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm^-1 band and an increase in the 870 cm^-1 band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.

Effects of Brown and Green Propolis on Bond Strength of Fiberglass Posts to Root Canal Dentin

Introduction

The purpose of this study was to evaluate the effect of brown and green propolis on bond strength of the fiberglass posts to root canal dentin, and to compare it with conventional endodontic irrigants.

Methods and Materials

Sixty bovine teeth were selected, decoronated and randomly distributed into six groups (n=10), according to the irrigation solution: 0.9% saline solution (Control); 2% chlorhexidine (CHX); 5% malic acid (MA); 0.5% ethanolic extract of brown propolis (BP); 0.25% ethanolic extract of green propolis (GP); 2.5% sodium hypochlorite (NaOCl). After root canal treatment, fiber posts were cemented into prepared root canals with a self-adhesive resin cement. The roots were cross-sectioned to obtain two discs from each third and submitted to the micro push-out test. Failure patterns were evaluated under optical microscopy. The influence of irrigants agents was analyzed using one-way ANOVA followed by Games-Howell's test (α=0.05). Failure modes were analyzed using Fischer's exact test (α=0.05).

Results

There were statistically significant differences among the groups (P<0.05). The control, NaOCl and BP groups showed the highest bond strength with no statistically significant difference between them (P>0.05). Adhesive failure type was the predominant in all groups.

Conclusion

Based on this in vitro study, the use of 0.5% brown propolis did not influence the bond strength of fiberglass posts to root canal dentin, while the use of 0.25% green propolis did affect it negatively.

Effectiveness of Sodium Hypochlorite plus EDTA Compared with Peracetic Acid in Removing Smear Layer and Killing Enterococcus faecalis

Introduction

The aim of this study was to evaluate the effectiveness of 2.5% sodium hypochlorite associated with 17% Ethylenediaminetetraacetic acid (NaOCl-EDTA), versus that of 1% peracetic acid (PA), in removing the smear layer, as assessed by scanning electron microscopy (SEM), and in exerting bactericidal action against Enterococcus faecalis (E. faecalis ) , as assessed by the real-time polymerase chain reaction (real-time PCR).

Methods and Materials

Fifty-five extracted mandibular single-rooted premolars were selected, and divided into two experimental groups (NaOCl-EDTA and PA; n=25) and one control group (0.9% saline; n=5). Pre- and post-instrumentation samples were collected and assessed for the presence of E. faecalis using real-time PCR. The teeth were instrumented using hand files and the ProTaper Universal system (hybrid technique) for a standardized time of 7 min. A total of 20 mL of NaOCl followed by 5 mL of EDTA were applied during instrumentation in the NaOCl-EDTA group, whereas 20 mL of PA and 20 mL of saline were applied in the PA and control groups, respectively. An additional 5 mL of saline was applied in all the groups to neutralize the environment. A scoring system was used to conduct the SEM assessment. The results were submitted to the Kruskal-Wallis test, complemented by Dunn's test (SEM analysis) (P<0.05).

Results

A significant microbial reduction was observed in both the PA and the NaOCl-EDTA groups (P<0.05). In the PA group, the presence of a smear layer in the apical third was significantly greater than in the cervical third (P<0.05); no significant differences were observed between the middle and cervical thirds, or between the middle and apical thirds (P>0.05). In the NaOCl-EDTA group, the smear layer scores were significantly higher in the apical third than in the cervical and middle thirds (P<0.05).

Conclusion

This in vitro study showed that there was no significant difference between PA and NaOCl-EDTA irrigation regimens regarding either antimicrobial action against E. faecalis or removal of the smear layer, except for greater removal in the middle third by the NaOCl-EDTA group.