Tracing the toxic ions of an endodontic tricalcium silicate-based sealer in local tissues and body organs

Evaluation of the Genotoxicity and Cytotoxicity of Bioceramic Endodontic Sealers in HepG2 and V79 Cell Lines: An In Vitro Study Using the Comet and Micronucleus Assays

BACKGROUND

The primary objective of this study was to evaluate the cytotoxic and genotoxic effects of calcium silicate-based sealers (BioRoot RCS and MTA Fillapex) compared to an epoxy-based sealer (AH Plus).

MATERIALS AND METHODS

The study was conducted in vitro with the cell lines HepG2 and V79 to evaluate cytotoxicity and genotoxicity using the comet and micronucleus assays. Eluates of the materials were tested at two different concentrations (3 cm2/mL and 0.5 cm2/mL) after an exposure time of 72 h. Data were analyzed using the Mann-Whitney and Kruskal-Wallis tests (p < 0.05).

RESULTS

At lower concentrations in both cell lines, MTA Fillapex showed no significant difference in the measured comet assay parameters compared to the negative control (p > 0.05). In addition, it showed significantly lower genotoxic effects compared to AH Plus for all comet assay parameters, concentrations, and cell lines (p ≤ 0.001). BioRoot RCS showed lower primary DNA damage (p ≤ 0.001) than AH Plus, only at higher concentrations and in the HepG2 cell line. Concerning the two tested bioceramic sealers, BioRoot RCS showed higher tail intensity values compared to MTA Fillapex (p < 0.05). In contrast to the results of the comet assay, BioRoot RCS significantly reduced the number of nuclear buds and nucleoplasmic bridges in the HepG2 cell line compared to MTA Fillapex, whereas reduction in the V79 cell line was only observed for nuclear buds (p < 0.05). Both materials increased the number of apoptotic cells compared to the negative control (p < 0.05). In comparison to AH Plus, BioRoot RCS and MTA Fillapex significantly reduced the number of cells with micronuclei and increased the number of cells with undamaged chromatin (p < 0.05).

CONCLUSIONS

The findings suggest that MTA Fillapex and BioRoot RCS exhibit superior biocompatibility over AH Plus, as evidenced by their lower cytotoxic and genotoxic effects in vitro. These results support the use of calcium silicate-based sealers in clinical practice, highlighting the need for further studies to evaluate their performance in vivo and their implications for patient safety.

Evaluation of the systemic effect of bone formation marker released by endodontic calcium silicate-based sealers in local tissues, the bloodstream, and body organs

Calcium silicate-based sealers are bioactive materials that release ions when in contact with body fluids. Therefore, this study aims mapping/trace bone formation markers released by MTA Fillapex, BioRoot RCS, and experimental tricalcium silicate-based sealer (CEO) into subcutaneous tissues, bloodstream and body organs. Toward, polyethylene tubes filled with sealers were implanted into connective tissue of Wistar rats. On days 7, 15, 30, and 45 after implantation, blood samples were collected to measure calcium (Ca2+), phosphorus (P), and alkaline phosphatase (ALP) levels. Thereafter, the animals were killed, and the brain, liver, kidneys, and subcutaneous tissue were removed and processed to determine the concentrations of Ca2+ and P by ICP-OES. Similar Ca2+ levels were observed in subcutaneous tissue for all groups, although, at 45 days, it was identified a reduction in Ca2+ serum levels of CEO compared to those two other sealers and an increase in Ca2+ levels in the liver compared to those released by MTA Fillapex. In contrast, no trace of P was detected in any tissue; moreover, plasma P and ALP serum levels of MTA Fillapex were higher at day 30. Our findings showed that Ca2+ were identified in local tissues, bloodstream, and organs from all sealers. The up-regulation of bone marker levels promoted by sealers can modify body homeostasis and induce tissue damage. Besides, MTA Fillapex was associated with a raise of bone marker levels, suggesting a possible systemic effect. The sealer composition can affect not only the local repair process but also the systemic health.

Evaluating the antimicrobial effectiveness of endodontic sealers against oral pathogens associated with failed root canal treatments

Overview

Residual pathogens lead to treatment failure. Microbes like Enterococcus faecalis, Candida albicans, and Actinomyces israelii are often isolated after failed root canal therapy. Therefore, the antimicrobial efficacy of sealers is critical for treatment outcomes.

Aim

To evaluate the antimicrobial efficacy of endodontic sealers against E. faecalis and C. albicans.

Methodology

The agar diffusion test was used to evaluate the antibacterial efficacy of four sealers: MTA Fillapex, Bio-C-Sealer, Sealapex, and Seal-Pex. Each microorganism's bacterial suspension was added to agar plates separately. The sterile discs were then placed on the plates; later, a freshly mixed sealer was coated on the sterile discs. After 24 h of incubation, inhibition zones were measured.

Results

The Kruskal-Wallis test was used to analyze the data, and the Mann-Whitney U-test was used for post hoc pairwise comparison. The results demonstrated that Seal-Pex has potent antibacterial activity against E. faecalis (P < 0.05). Against C. albicans, both MTA Fillapex and Seal-Pex were effective, with MTA Fillapex showing a statistically significant difference compared to Bio-C Sealer and Sealapex.

Conclusion

Seal-Pex, an epoxy resin-based sealer, exhibited a significant antimicrobial efficacy against E. faecalis. Conversely, MTA Fillapex demonstrated notable antifungal activity against C. albicans, surpassing other tested sealers. These findings highlight the differential antimicrobial and antifungal properties of the sealers.

Physicochemical properties and biological interaction of calcium silicate-based sealers - in vivo model

OBJECTIVES

To investigate volumetric changes, in vivo biocompatibility, and systemic migration from eight commercial endodontic sealer materials in paste/paste, powder/liquid, and pre-mixed forms.

MATERIALS AND METHODS

The sealers AH Plus Bioceramic, AH Plus Jet, BioRoot RCS, MTApex, Bio-C Sealer, Bio-C Sealer Ion+, EndoSequence BC Sealer and NeoSEALER Flo were studied. After characterisation by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy and X-ray diffractometry (XRD), tubes were implanted in Wistar rats' alveolar bone and subcutaneous tissues. Micro-CT evaluated volumetric changes pre/post 30 days of implantation. Histological and immunohistochemistry analyses assessed biocompatibility. Kidney samples underwent spectrometry (ICP-MS) for tantalum, tungsten and zirconium. Statistical analysis determined normality and significance (udp < 0.05).

RESULTS

Characterisation revealed calcium, silicon, and radiopacifiers in the materials. Volumetric changes showed greater alteration in subcutaneous tissues than alveolar bone; BioRoot RCS and MTApex (powder/liquid) were most stable. Histological analysis indicated intense inflammation for AH Plus Jet, moderate for others; IL-10 was marked positively for all materials. AH Plus Jet had an 18-fold higher tungsten and a 37-fold higher zirconium mass fraction in kidneys versus controls, while tantalum showed lower accumulation patterns.

CONCLUSION

Root canal filling materials' responses varied by implantation site and form, demonstrating acceptable biocompatibility. Tantalum and zirconium oxide radiopacifiers appear systemically safe; tungsten-based radiopacifiers are unsuitable due to metal accumulation risks.

CLINICAL RELEVANCE

This study highlights the need for further in vivo studies on endodontic sealers' chemical, biological, and physical behaviors and their systemic migration.

The efficacy of premixed bioceramic sealers versus standard sealers on root canal treatment outcome, extrusion rate and post-obturation pain: A systematic review and meta-analysis

BACKGROUND

Limited evidence is available regarding the superior clinical properties of bioceramic sealers comparted with traditional standard sealers.

OBJECTIVES

This review aimed to answer the following research questions: 'In healthy patients requiring a root canal treatment (P), what is the efficacy of premixed bioceramic sealers (I) compared with traditional root canal epoxy resin-based sealers (C) in terms of survival, success rates (PICO1) sealer extrusion and resorption (PICO2) post-obturation pain (PICO3) (O)?'

METHODS

Authors independently searched three electronic databases: PubMed (including MEDLINE), Web of Science, Embase and Scopus up to 31 October 2023. This was accompanied by both grey literature and manual search. Detailed selection criteria were applied, namely mature permanent teeth requiring root canal treatment, premixed bioceramic sealer with gutta-percha as an intervention group, a standard filling technique as control group and full-text available in English. A random-effect meta-analysis was used to synthesize the body of evidence regarding the use of bioceramic sealers in root canal treatment and their impact on post-obturation pain. Effect sizes were represented as relative risks on a logarithmic scale for binary outcomes and as mean differences for continuous outcomes.

RESULTS

A total of 941 articles were identified. Fifteen Comparative clinical studies were finally included. Eleven were randomized clinical trials, and four were prospective clinical trials with control group. The follow-up of these studies was not greater than 2 years. No publication bias was observed in any study. No significant differences were observed between the two groups in terms of survival and success rates. A small non-significant lower risk of extrusion was observed for bioceramics. A small, non-significantly lower post-operative-pain within 24-h was observed when bioceramics were used.

DISCUSSION

The majority of current evidence shows inconsistencies in reporting and is of short-term duration. Robust prospective long-term trials are needed in this area to better support future recommendations.

CONCLUSION

This systematic review is the first to analyse several clinical outcomes using premixed sealers. Included studies differed in terms of clinical protocol and operator expertise, but reported a similar outcome when comparing bioceramic versus standard sealers. Tooth survival, treatment outcome, post-operative pain and periapical extrusion were similar and presented no significant differences between the two sealer types.

REGISTRATION

PROSPERO database (CRD42023449151).

In silico toxicity and immunological interactions of components of calcium silicate-based and epoxy resin-based endodontic sealers

OBJECTIVES

The present study aimed to determine in silico toxicity predictions of test compounds from hydraulic calcium silicate-based sealers (HCSBS) and AH Plus and computationally simulate the interaction between these substances and mediators of periapical inflammation via molecular docking.

MATERIALS AND METHODS

All chemical information of the test compounds was obtained from the PubChem site. Predictions for bioavailability and toxicity analyses were determined by the Molinspiration Cheminformatics, pkCSM, ProTox-II and OSIRIS Property Explorer platforms. Molecular docking was performed using the Autodock4 AMDock v.1.5.2 program to analyse interactions between proteins (IL-1β, IL-6, IL-8, IL-10 and TNF-α) and ligands (calcium silicate hydrate, zirconium oxide, bisphenol-A epoxy resin, dibenzylamine, iron oxide and calcium tungstate) to establish the affinity and bonding mode between systems.

RESULTS

Bisphenol-A epoxy resin had the lowest maximum dose tolerated in humans and was the test compound with the largest number of toxicological properties (hepatotoxicity, carcinogenicity and irritant). All systems had favourable molecular docking. However, the ligands bisphenol-A epoxy resin and dibenzylamine had the greatest affinity with the cytokines tested.

CONCLUSION

In silico predictions and molecular docking pointed the higher toxicity and greater interaction with mediators of periapical inflammation of the main test compounds from AH Plus compared to those from HCSBS.

CLINICAL RELEVANCE

This is the first in silico study involving endodontic materials and may serve as the basis for further research that can generate more data, producing knowledge on the interference of each chemical compound in the composition of different root canal sealers.

A Review of the research methods and progress of biocompatibility evaluation of root canal sealers

The function of root canal sealer was to achieve an appropriate three-dimensional filling effect by filling the root canal and some irregular lumen, thereby inhibiting the residual bacteria. There were many types of sealers, but research to find the most suitable ones was still ongoing. In recent years, researchers had continuously improved the performance of sealers by developing new sealers or adding active ingredients to the sealers. However, most sealers exhibit varying degrees of cytotoxicity and tissue responses, which affect clinical therapy efficacy. This review describes different technical approaches, and recent research progress in the biocompatibility evaluation of root canal sealers and provides brief insights into this field by summarising the performance studies of different root canal sealers.