The evaluation of cytotoxicity and cytokine IL-6 production of root canal sealers with and without the incorporation of simvastatin: an invitro study

Characterisation and evaluation of physical properties of AH-Plus sealer with and without the incorporation of petasin, pachymic acid, curcumin and shilajit-an invitro study

BACKGROUND

AH Plus, an epoxy resin-based sealer, is widely used in endodontic practice, owing to its good physical properties that confers longstanding dimensional stability and good adhesion to dentin. Nevertheless, its propensity to trigger inflammation, especially in its freshly mixed state, has been extensively documented. Phytochemicals such as Petasin, Pachymic acid, Curcumin, and Shilajit are known for their anti-inflammatory and analgesic effects. This study aimed to analyze and determine the effect of these natural products on the physical properties of AH Plus sealer when incorporated with the sealer.

METHODS

AH Plus (AHR) sealer was mixed with 10% petasin, 0.75% pachymic, 0.5% and 6%shilajit to obtain AHP, AHA, AHC and AHS in the ratio of 10:1 and 5:1 respectively. Five samples of each material were assessed for setting time, solubility, flow, and dimensional stability in accordance with the ISO 6876:2012 standardization. Sealers were characterized through scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Statistical evaluation involved the Kolmogorov-Smirnov and Shapiro-Wilks tests for normality and the one-way ANOVA test for analysis.

RESULTS

In this investigation, the characterisation analysis revealed a relatively similar microstructure in all the experimental root canal sealers. All experimental groups, excluding the control group, exhibited an increase in flow ranging from 11.9 to 31.4% at a 10:1 ratio. Similarly, for the 5:1 ratio, the increase ranged from 12.02 to 31.83%. In terms of dimensional stability, all groups at the 10:1 ratio showed a decrease compared to the control group. The addition of natural agents to AHR in 10:1 ratio led to a reduction in setting time by 8.9-31.6%, and at a 5:1 ratio, the reduction ranged from 8.1 to 31.5%. However, regarding solubility, the addition of natural agents did not induce any significant alterations.

CONCLUSION

Based on the results of this study, it can be concluded that all tested root canal sealers exhibited properties that met the acceptable criteria outlined in the ISO 6876:2012 standardization.

In vitro and in silico evaluation of the design of nano-phyto-drug candidate for oral use against Staphylococcus aureus

Onopordum acanthium is a medicinal plant with many important properties, such as antibacterial, anticancer, and anti-hypotensive properties. Although various studies reported the biological activities of O. acanthium, there is no study on its nano-phyto-drug formulation. The aim of this study is to develop a candidate nano-drug based on phytotherapeutic constituents and evaluate its efficiency in vitro and in silico. In this context, poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) of O. acanthium extract (OAE) were synthesized and characterized. It was determined that the average particle size of OAE-PLGA-NPs was 214.9 ± 6.77 nm, and the zeta potential was -8.03 ± 0.85 mV, and PdI value was 0.064 ± 0.013. The encapsulation efficiency of OAE-PLGA-NPs was calculated as 91%, and the loading capacity as 75.83%. The in vitro drug release study showed that OAE was released from the PLGA NPs with 99.39% over the 6 days. Furthermore, the mutagenic and cytotoxic activity of free OAE and OAE-PLGA-NPs were evaluated by the Ames test and MTT test, respectively. Although 0.75 and 0.37 mg/mL free OAE concentrations caused both frameshift mutation and base pair substitution (p < 0.05), the administered OAE-PLGA NP concentrations were not mutagenic. It was determined with the MTT analysis that the doses of 0.75 and 1.5 mg/mL of free OAE had a cytotoxic effect on the L929 fibroblast cell line (p < 0.05), and OAE-PLGA-NPs had no cytotoxic effect. Moreover, the interaction between the OAE and S. aureus was also investigated using the molecular docking analysis method. The molecular docking and molecular dynamics (MD) results were implemented to elucidate the S. aureus MurE inhibition potential of OAE. It was shown that quercetin in the OAE content interacted significantly with the substantial residues in the catalytic pocket of the S. aureus MurE enzyme, and quercetin performed four hydrogen bond interactions corresponding to a low binding energy of -6.77 kcal/mol with catalytic pocket binding residues, which are crucial for the inhibition mechanism of S. aureus MurE. Finally, the bacterial inhibition values of free OAE and OAE-PLGA NPs were determined against S. aureus using a microdilution method. The antibacterial results showed that the inhibition value of the OAE-PLGA NPs was 69%. In conclusion, from the in vitro and in silico results of the nano-sized OAE-PLGA NP formulation produced in this study, it was evaluated that the formulation may be recommended as a safe and effective nano-phyto-drug candidate against S. aureus.

Immunomodulatory Effects of Endodontic Sealers: A Systematic Review

Inflammation is a crucial step prior to healing, and the regulatory effects of endodontic materials on the immune response can influence tissue repair. This review aimed to answer whether endodontic sealers can modulate the immune cells and inflammation. An electronic search in Scopus, Web of Science, PubMed, and Google Scholar databases were performed. This systematic review was mainly based on PRISMA guidelines, and the risk of bias was evaluated by SYRCLEs and the Modified CONSORT checklist for in vivo and in vitro studies, respectively. In total, 28 articles: 22 in vitro studies, and six in vivo studies were included in this systematic review. AH Plus and AH 26 can down-regulate iNOS mRNA, while S-PRG sealers can down-regulate p65 of NF-κB pathways to inhibit the production of TNF-α, IL-1, and IL-6. In vitro and in vivo studies suggested that various endodontic sealers exhibited immunomodulatory impact in macrophages polarization and inflammatory cytokine production, which could promote healing, tissue repair, and inhibit inflammation. Since the paradigm change from immune inert biomaterials to bioactive materials, endodontic materials, particularly sealers, are required to have modulatory effects in clinical conditions. New generations of endodontic sealers could hamper detrimental inflammatory responses and maintain periodontal tissue, which represent a breakthrough in biocompatibility and functionality of endodontic biomaterials.