Antibacterial Efficacy of Synthetic and Natural-Derived Novel Endodontic Irrigant Solutions

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.

Effect of sodium/calcium hypochlorite on adhesion and adaptation of fiber posts luted with a dual resin cement

This study aimed to evaluate the effect of different concentrations of sodium hypochlorite (NaOCl) and calcium hypochlorite [Ca(OCl)2] on the bond strength and adaptation of glass fiber posts luted with a dual-curing resin cement. Fifty decoronated premolars were sectioned 14 mm from the apex and endodontically treated. The root canal filling was partially removed. The specimens were divided into 5 groups (n=10) according to the irrigant for post space irrigation: 0.9% sodium chloride (NaCl), (control); 2.5% NaOCl; 5.25% NaOCl; 2.5% Ca(OCl)2; and 5.25% Ca(OCl)2. For each group, irrigation was performed with 5 ml of solution. Afterward, the posts were luted with a dual-curing resin cement. One slice from each third was obtained and submitted to the push-out test and failure modes analysis. An additional slice from the middle third was submitted to confocal images for analysis of adaptation failures (gaps). Two-way ANOVA, Tukey's post-hoc, Kruskal-Wallis with Bonferroni adjusted, and chi-square tests, analyzed data. The group treated with 5.25% NaOCl showed lower bond strength values and generated more cohesive failures compared to the control (p < 0.05). Bond strength decreased from coronal to apical in the post space (p < 0.001). The groups treated with NaOCl had the highest percentages of gaps compared to the control (p < 0.05). Regardless of concentration, Ca(OCl)2 did not influence the bond strength and the occurrence of gaps (P > 0.05). Ca(OCl)2 is a good option for irrigating the post space before luting a fiber post with a dual-curing resin cement.

Comparative analysis of peracetic acid (PAA) and permaleic acid (PMA) in disinfection processes

The growing demand to reduce chlorine usage and control disinfection byproducts increased the development of new strategies in wastewater treatments. Organic peracids are increasingly attracting interest in disinfection activities as a promising alternative to chlorine and chlorine-based agents. In this study, we assessed the antimicrobial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of a new organic peracid, permaleic acid (PMA) compared with the reference peracetic acid (PAA). Disinfectant properties were evaluated by i) disk diffusion agar, ii) broth microdilution, iii) antibiofilm properties. PMA demonstrated a 10- and 5-fold decrease in the microbial inhibitory concentration (MIC) value against E. coli and S. aureus respectively, compared to PAA. Results showed greater efficacy of PMA regarding wastewater (WW) and treated wastewater (TWW) disinfection at low concentrations. Furthermore, the biofilm degradation ability was only observed following PMA treatment, for both strains. Bacterial regrowth from biofilm matrix after PAA and PMA disinfection, in the absence and presence of organic matter, was evaluated. PMA was more efficient than PAA to prevent the regrowth of planktonic cells of S. aureus and E. coli. After PAA and PMA treatment, in the presence of organic matter, the bacterial regrowth inhibition was maintained up to 10 and 5 g/L, respectively. Based on these results, PMA could be used as a valid alternative to the currently used disinfection methods.

Environmental sustainability in endodontics. A life cycle assessment (LCA) of a root canal treatment procedure

Background

To analyse via life cycle analysis (LCA) the global resource use and environmental output of the endodontic procedure.

Methodology

An LCA was conducted to measure the life cycle of a standard/routine two-visit RCT. The LCA was conducted according to the International Organization of Standardization guidelines; ISO 14040:2006. All clinical elements of an endodontic treatment (RCT) were input into OpenLCA software using process and flows from the ecoinvent database. Travel to and from the dental clinic was not included. Environmental outputs included abiotic depletion, acidification, freshwater ecotoxicity/eutrophication, human toxicity, cancer/non cancer effects, ionizing radiation, global warming, marine eutrophication, ozone depletion, photochemical ozone formation and terrestrial eutrophication.

Results

An RCT procedure contributes 4.9 kg of carbon dioxide equivalent (CO2 eq) emissions. This is the equivalent of a 30 km drive in a small car. The main 5 contributors were dental clothing followed by surface disinfection (isopropanol), disposable bib (paper and plastic), single-use stainless steel instruments and electricity use. Although this LCA has illustrated the effect endodontic treatment has on the environment, there are a number of limitations that may influence the validity of the results.

Conclusions

The endodontic team need to consider how they can reduce the environmental burden of endodontic care. One immediate area of focus might be to consider alternatives to isopropyl alcohol, and look at paper, single use instrument and electricity use. Longer term, research into environmentally-friendly medicaments should continue to investigate the replacement of current cytotoxic gold standards with possible natural alternatives. Minimally invasive regenerative endodontics techniques designed to stimulate repair or regeneration of damaged pulp tissue may also be one way of improving the environmental impact of an RCT.

Evaluation of the biological properties of two experimental calcium silicate sealers: an in vivo study in rats

AIM

To evaluate the biological properties of experimental sealers based on tricalcium silicate and dicalcium silicate, manipulated with polyethylene glycol (CE-1) and with the addition of calcium hypochlorite (CE-2) compared to AH Plus (AHP) and TotalFill BC Sealer (TBC).

METHODOLOGY

The tissue reaction caused by the materials in the subcutaneous tissue of rats was evaluated after implantation of polyethylene tubes filled with the materials at 7, 15, 30 and 60 days. Sections were stained with haematoxylin and eosin (HE) for morphological analysis and to evaluated number of inflammatory cells/mm² (ICs). Sections were used for immunohistochemical detection of interleukin-6 (IL-6) and osteocalcin (OC). The von Kossa method was used to identify calcium precipitation in the capsules. The data were submitted to anova and Tukey's tests, with 5% significance level.

RESULTS

At 7 days, CE-1, CE-2 and AHP had higher numbers of ICs. AHP presented higher immunolabelling for IL-6. After 15 days, regarding IL-6, there was no difference between CE-2 and the control group. At 30 days, AHP exhibited the highest number of IC (P < 0.05) and CE-2 and the control group presented the lowest ICs and IL-6-positive cells. After 60 days, all materials exhibited decreases in ICs. CE-2, TBC and the control had the lowest values (P < 0.05). No significant difference was detected between CE-1 and TBC, and between CE-2 and control considering the immunoexpression of IL-6. In this period, AHP had the greatest number of IC and IL-6 (P < 0.05). In all periods, CE-1, CE-2 and TBC sealers had von Kossa-positive structures and OC-immunolabelled cells. CE-2 had higher number of OC-positive cells than the CE-1 and TBC sealers (P < 0.05), in all periods. OC immunolabelling was not observed in the capsules of AH Plus and the control groups.

CONCLUSIONS

The experimental sealer and its association with calcium hypochlorite, in addition to TotalFill BC Sealer, were biocompatible and had bioactive potential.

Antibacterial Efficacy of the Grape Seed Extract as an Irrigant for Root Canal Preparation

Objective:

The purpose of this research was to compare relative effectiveness of sodium hypochlorite 5.25% (NaOCl), 2% chlorhexidine gel (CHX) and 6.5 % grape seed extract (GSE) against Enterococcus faecalis using instrument Reciproc R25 in root canal preparation.

Methods:

Forty-five mesiobuccal root canals from extracted human maxillary molars were collected and infected with Enterococcus faecalis. The samples were divided into five groups according to the different types of irrigants: saline (positive control) (n=5); in the other groups were used 10 root canals for each group: NaOCl+EDTA; CHX gel+EDTA; GSE solution+EDTA; GSE gel+EDTA. All the groups were prepared with reciprocating instruments Reciproc R25. Bacterial reduction was measured by two-way ANOVA (P<0.001) followed by Tukey HSD post-hoc tests, from the counting of colony forming units (CFUs) from samples collected before instrumentation and after. The significance level established at 5% (P<0.05).

Results:

The group prepared with the NaOCl resulted in highest antimicrobial capacity among of all (P>0.05), followed by CHX and GSE gel (P<0.05). Control and GSE solution showed similar results (P<0.05) and resulted in the lowest percentage of the reduction of the microorganism into the root canals.

Conclusion:

NaOCl had the higher elimination capacity of Enterococcus faecalis than GSE and CHX.