Effect of iRoot SP and mineral trioxide aggregate (MTA) on the viability and polarization of macrophages

Effects of direct pulp capping with recombinant human erythropoietin and/or mineral trioxide aggregate on inflamed rat dental pulp

OBJECTIVE

This study aimed to evaluate the dental pulp responses to recombinant human erythropoietin (rhEPO) and/or mineral trioxide aggregate (MTA) in pulp capping of inflamed dental pulp in vivo.

MATERIALS AND METHODS

In accordance with ARRIVE guidelines, pulp inflammation was induced by exposing the maxillary first molars (n = 64) of Wistar rats (n = 32) to the oral environment for two days. The exposed pulps were randomly assigned four groups based on the pulp capping material: rhEPO, MTA, MTA + rhEPO, or an inert membrane. An additional eight rats formed the healthy control group. After four weeks, the animals were euthanized, and histological, qRT-PCR, and spectrophotometric techniques were employed to analyze the left maxillary segments, right first maxillary molars, and blood samples, respectively. Statistical significance was set at p < 0.05 and < 0.001.

RESULTS

Pulp capping with rhEPO, MTA, or MTA + rhEPO resulted in lower inflammation and higher mineralization scores compared to untreated control. MTA + rhEPO group exhibited significantly decreased expression of tumor necrosis factor-alpha, and interleukin 1-beta, while MTA group showed substantially reduced expression of interferon-gamma. Both rhEPO and MTA + rhEPO groups presented elevated dentin matrix protein 1 levels compared to untreated control. Furthermore, pulp capping with rhEPO and/or MTA led to increased transforming growth factor-beta 1 expression and reductions of pro-inflammatory/immunoregulatory cytokine ratios and prooxidative markers. Pulp capping with rhEPO also resulted in increase of systemic antioxidative stress markers.

CONCLUSION

Capping with rhEPO or MTA + rhEPO resulted in a favorable effect that was similar or even superior to that of MTA.

The bioceramic sealer iRoot SP promotes osteogenic differentiation of human stem cells from apical papilla via miR-141-3p/SPAG9/MAPK signalling pathway

AIM

The premixed bioceramic sealer iRoot SP that is widely used clinically has been reported to kill bacterial biofilms and promote osteogenic differentiation of human stem cells from the apical papilla (hSCAPs). Although miR-141-3p has been substantiated to be involved in the osteogenic process, the underlying mechanisms remain unclear. The aim of this study was to investigate the role of miR-141-3p in osteogenic differentiation and underlying mechanisms of iRoot SP-treated hSCAPs.

METHODOLOGY

hSCAPs were extracted from tissue blocks with enzyme digestion and identified by using immunofluorescence, flow cytometry and alizarin red staining. The mRNA expression level of miR-141-3p in hSCPAs after culture with iRoot SP was examined by quantitative real-time PCR (qRT-PCR) assay. SPAG9 was identified as a downstream target gene of miR-141-3p by dual-luciferase report assay. Alkaline phosphatase (ALP) staining and activity detection, alizarin red staining, calcium concentration assay, qRT-PCR and western blot were used to estimate osteogenic differentiation ability and involved protein expression levels of the osteogenic makers and signalling pathway-related factors in iRoot SP-treated hSCAPs. Data were analysed by one-way anova and post hoc Tukey's test to determine any statistical differences between the experimental groups and the control group. p < .05 was considered statistically significant.

RESULTS

Expression of miR-141-3p was reduced in iRoot SP-treated hSCAPs with the increased exposure time up to 7 days, and the western blot and qRT-PCR results revealed that the osteogenic markers osteocalcin (OCN), osterix (OSX), runt-related transcription factor 2 (RUNX2) and dentin sialophosphoprotein (DSPP) were inversely correlated with miR-141-3p. The negative regulatory relationship between miR-141-3p and SPAG9/ mitogen-activated protein kinases (MAPK) signalling axis was validated in this in vitro experiments.

CONCLUSIONS

The bioceramic sealer iRoot SP promoted osteogenic differentiation of hSCAPs by inhibiting miR-141-3p following down-regulated SPAG9 expression, and activated MAPK pathway. These findings proposed a novel therapeutic impact of bioceramic sealer iRoot SP inducing bone regeneration in refractory periapical periodontitis.

Bioceramics in Endodontics: Updates and Future Perspectives

Bioceramics, with excellent bioactivity and biocompatibility, have been widely used in dentistry, particularly in endodontics. Mineral trioxide aggregate (MTA) is the most widely used bioceramic in endodontics. Recently, many new bioceramics have been developed, showing good potential for the treatment of endodontic diseases. This paper reviews the characteristics of bioceramics and their applications in various clinical endodontic situations, including root-end filling, root canal therapy, vital pulp therapy, apexification/regenerative endodontic treatment, perforation repair, and root defect repair. Relevant literature published from 1993 to 2023 was searched by keywords in PubMed and Web of Science. Current evidence supports the predictable outcome of MTA in the treatment of endodontic diseases. Although novel bioceramics such as Biodentine, EndoSequence, and calcium-enriched mixtures have shown promising clinical outcomes, more well-controlled clinical trials are still needed to provide high-level evidence for their application in endodontics. In addition, to better tackle the clinical challenges in endodontics, efforts are needed to improve the bioactivity of bioceramics, particularly to enhance their antimicrobial activity and mechanical properties and reduce their setting time and solubility.

Bioactivity analysis of calcium silicate-based sealers and repair cements on the phenotype and cytokine secretion profile of CD14+ monocytes: An ex vivo study

AIM

This study evaluated the immune bioactivity of testing media (TM) obtained from different calcium silicate-based sealers and cements on monocyte morphology, activation, differentiation and cytokine secretion.

METHODS

Blood-derived CD14⁺ monocytes were isolated and cultured for 5 days with 25% TM from the following calcium silicate-based materials: TotalFill BC RRM Fast-Set Putty, Biodentine, TotalFill BC Sealer and BioRoot-Root-Canal-Sealer (RCS). A resin-based endodontic cement was used as a control. The expression of surface markers such as CD86, HLA-DR, CD16, CD309 and CD209, and cytokine secretion were analysed by flow cytometry. Data were analysed using the one-way repeated measures analysis of variance (anova) multiple comparison test and a Holm-Sidak multiple comparison post-hoc test (p < .05).

RESULTS

This comparative analysis revealed that monocytes co-cultured with calcium silicate-based materials showed a spindle-shaped morphology compared with the round shape observed in the control. Regarding activation markers, BioRoot-RCS and Biodentine significantly increased CD86 expression compared with the control sample, whereas no significant differences (p > .05) were observed in HLA-DR expression. In addition, no differences were observed among the differentiation markers. When the inflammatory cytokines were analysed, BioRoot-RCS increased the secretion of IL-1β, IL-6, IL-10 and TNF-α, whereas BioRoot-RCS and Biodentine significantly decreased IL-8 production (p < .05).

CONCLUSIONS

These data showed that the calcium silicate-based materials tested changed the morphology of CD14⁺ monocytes; however, only BioRoot-RCS and Biodentine significantly upregulated CD86. In addition, BioRoot-RCS was the sealer with the highest immunomodulatory properties for cytokine production which means that it can contribute with the in vivo healing process and regeneration of periapical lesions.

Biological Evaluation of the Effect of Root Canal Sealers Using a Rat Model

Gutta-percha points and root canal sealers have been used for decades in endodontics for root canal obturation. With techniques such as single cone methods, the amount of sealer is larger, making their properties more critical. However, relatively few reports have comprehensively evaluated their biological effects. To this end, we evaluated three types of sealers, zinc oxide-fatty acid-, bio-glass- and methacrylate resin-containing sealers were considered. Their biological effects were evaluated using a rat subcutaneous implantation model. Each sealer was loaded inside a Teflon tube and implanted subcutaneously in the backs of rats. Inflammatory cells were observed around all samples 7 days after implantation and reduced after 28 days. Our results revealed that all samples were in contact with the subcutaneous tissue surrounding the sealer. Additionally, Ca and P accumulation was observed in only the bio-glass-containing sealer. Furthermore, each of the three sealers exhibited unique immune and inflammatory modulatory effects. In particular, bio-glass and methacrylate resin sealers were found to induce variable gene expression in adjacent subcutaneous tissues related to angiogenesis, wound healing, muscle tissue, and surrounding subcutaneous tissue. These results may help to understand the biological impacts of root canal sealers on surrounding biological tissues, guiding future research and comparisons with new generations of materials.

M1 and M2 macrophages phenotypes modulation after stimuli with materials used in endodontic treatment

The aim of this study was to evaluate the M1 and M2 macrophage modulation after stimuli with different materials used during endodontic treatment. In bone marrow-derived macrophage cell culture, from males C57BL/6 wild-type (WT) mice, gene expression analysis of markers to M1 and M2 macrophages was performed by qRT-PCR (Cxcl10, CxCL9, iNOS, Arg1, Chil3, Retnla and MRC1) and cytokine quantification by Luminex® (GM-CSF, IL-10, IL-6, IL-1β and TNF-α) after exposure to the five endodontic sealers: AH Plus, Sealapex Xpress, Endosequence BC Sealer, BioRoot RCS and a calcium hydroxide-based paste. For normal values, ANOVA test was used, followed by Tukey post-test. For non-normal values, the Kruskall-Wallis test was used. BioRootTM RCS and EndoSequence BC SealerTM stimulated the highest expression of markers for M1 macrophages, while calcium hydroxide-based paste stimulated the lowest expression of these gene markers. For M2 protein markers, BioRootTM RCS presented the highest stimulation while calcium hydroxide-based paste also presented the lowest stimulation. It was concluded that all the evaluated filling materials increased the genetic expression of pro- and anti-inflammatory markers: TNF-α and IL-10 respectively. The others proinflammatory mediators showed differences against the filling materials. However, this process did not induce the inflammatory response polarization, resulting in a hybrid macrophage.

Calcium Silicate-Based Root Canal Sealers: A Narrative Review and Clinical Perspectives

Over the last two decades, calcium silicate-based materials have grown in popularity. As root canal sealers, these formulations have been extensively investigated and compared with conventional sealers, such as zinc oxide-eugenol and epoxy resin-based sealers, in in vitro studies that showed their promising properties, especially their biocompatibility, antimicrobial properties, and certain bioactivity. However, the consequence of their higher solubility is a matter of debate and still needs to be clarified, because it may affect their long-term sealing ability. Unlike conventional sealers, those sealers are hydraulic, and their setting is conditioned by the presence of humidity. Current evidence reveals that the properties of calcium silicate-based sealers vary depending on their formulation. To date, only a few short-term investigations addressed the clinical outcome of calcium silicate-based root canal sealers. Their use has been showed to be mainly based on practitioners' clinical habits rather than manufacturers' recommendations or available evidence. However, their particular behavior implies modifications of the clinical protocol used for conventional sealers. This narrative review aimed to discuss the properties of calcium silicate-based sealers and their clinical implications, and to propose rational indications for these sealers based on the current knowledge.

In vitro biocompatibility and bioactivity of calcium silicate‑based bioceramics in endodontics (Review)

Calcium silicate-based bioceramics have been applied in endodontics as advantageous materials for years. In addition to excellent physical and chemical properties, the biocompatibility and bioactivity of calcium silicate-based bioceramics also serve an important role in endodontics according to previous research reports. Firstly, bioceramics affect cellular behavior of cells such as stem cells, osteoblasts, osteoclasts, fibroblasts and immune cells. On the other hand, cell reaction to bioceramics determines the effect of wound healing and tissue repair following bioceramics implantation. The aim of the present review was to provide an overview of calcium silicate-based bioceramics currently applied in endodontics, including mineral trioxide aggregate, Bioaggregate, Biodentine and iRoot, focusing on their in vitro biocompatibility and bioactivity. Understanding their underlying mechanism may help to ensure these materials are applied appropriately in endodontics.

Biocompatibility of Root Canal Sealers: A Systematic Review of In Vitro and In Vivo Studies

(1) Aim: To perform a systematic review of the literature on the biocompatibility of root canal sealers that encompasses the various types of sealers that are commercially available as well as both in vitro and in vivo evidence. (2) Methods: This systematic review has been registered in PROSPERO (ID 140445) and was carried out according to PRISMA guidelines using the following databases: PubMed, Cochrane Library, ClinicalTrials.gov, Science Direct, and Web of Science Core Collection. Studies published between 2000 and 11 June 2019 that evaluated cytotoxicity (cell viability/proliferation) and biocompatibility (tissue response) of root canal sealers were included. (3) Results: From a total of 1249 studies, 73 in vitro and 21 in vivo studies were included. In general, studies suggest that root canal sealers elicit mild to severe toxic effects and that several factors may influence biocompatibility, e.g., material setting condition and time, material concentration, and type of exposure. Bioactive endodontic sealers seem to exhibit a lower toxic potential in vitro. (4) Conclusions: The available evidence shows that root canal sealers exhibit variable toxic potential at the cellular and tissue level. However, the methodological heterogeneity among studies included in this systematic review and the somewhat conflicting results do not allow a conclusion on which type of sealer presents higher biocompatibility. Further research is crucial to achieve a better understanding of the biological effects of root canal sealers.

Analysis of Molecular Changes Induced By Mineral Trioxide Aggregate On sPLA2

The aim of this study was to analyze the effects of MTA on the structure and enzymatic activity of sPLA2 in order to provide subsidies for improvement in the formulation of the product. MTA powder was incubated for 60 min in the presence of sPLA2 and was analyzed by chromatography, electrospray mass (ESI-MS) and small-angle X-ray scattering (SAXS). It was find that the elution profile, retention time, and fragmentation of sPLA2 were altered after treatment with MTA. Calcium was the MTA component that most amplified the inflammatory signal. Significant interactions were found between MTA and sPLA2, which could aid in our understanding of the mechanisms of action of MTA during the inflammatory process and it may facilitate the structural modification of MTA, thereby improving its biological safety and consequently the rate of the treatment success.

Effects of mineral trioxide aggregate and bioceramics on macrophage differentiation and polarization in vitro

BACKGROUND/PURPOSE

Mineral trioxide aggregate (Pro-Root MTA, PR-MTA) and bioceramics (iRoot^® SP Injectable Root Canal Sealer, iR-BC) are used for making apical plugs used in apexification, repairing root perforations during root canal therapy, and treating internal root resorption. The purpose of the present in vitro study was to compare the biological effects of PR-MTA- and iR-BC-based dental sealers in the mouse macrophage cell line RAW 264.7.

METHODS

Cytotoxicity and cell proliferation were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell hemocytometer, respectively. Protein expression of biomarkers of cell proliferation, autophagy, and osteoclast differentiation was determined by western blotting. Pro-inflammatory gene expression was examined using quantitative reverse transcription-PCR.

RESULTS

PR-MTA induced cytotoxicity in RAW 264.7 cells in a dose-dependent manner, and iR-BC was more cytotoxic than PR-MTA. Low-dose and short-term treatments of both PR-MTA and iR-BC induced RAW 264.7 cell proliferation. PR-MTA induced autophagy, whereas iR-BC did not. Neither PR-MTA nor iR-BC induced osteoclastogenesis. Pro-inflammatory genes were activated by both materials. However, the expression of inducible nitric oxide synthase (iNOS) mRNA was upregulated by iR-BC treatment, but not by PR-MTA treatment.

CONCLUSION

Overall, dental PR-MTA and iR-BC induced pro-inflammatory genes but did not induce osteoclastogenesis in macrophages. PR-MTA and iR-BC induced M2 and M1 polarization, respectively, of RAW 264.7 cells.

Axl Involved in Mineral Trioxide Aggregate Induces Macrophage Polarization

INTRODUCTION

In this study, we examined the effect of mineral trioxide aggregate (MTA) on macrophage polarization and the potential involvement of Axl/nuclear factor kappa B (NF-κB) signaling in mediating the effect of MTA.

METHODS

The human monocyte cell line THP-1 was cultured with MTA solution for 1, 2, or 3 days, and the population change of M2 macrophages was analyzed by flow cytometry. Expression of M2 cytokines was examined by enzyme-linked immunosorbent assay. Phagocytosis and angiogenesis-induction ability were also assayed. The involvement of Axl/NF-κB signaling in MTA-treated cells was examined by analyzing phosphorylation status of Axl, Akt, IKKα/β, and IκBα. Specific inhibitors for Axl/Akt/NF-κB signaling were added to MTA-treated THP-1 cells, and their cytokine expression change was examined.

RESULTS

Flow cytometry analysis showed that MTA treatment increased CD206＋ cells in a time-dependent way. After MTA treatment, the expression of M2-related cytokines was up-regulated. MTA also enhanced phagocytic ability and the ability of THP-1 cells to induce angiogenesis. Treatment of MTA led to activate Axl/Akt/NF-kB signal axis by phosphorylation of Axl, Akt, IKKα/β, IκBα, and p65. In addition, MTA-induced interleukin 10, transforming growth factor beta, and vascular endothelial growth factor expression was suppressed as specific inhibitors were added.

CONCLUSIONS

Our findings indicate that MTA is able to induce macrophage polarization toward the M2 phenotype, with up-regulation of interleukin 10, transforming growth factor beta, and vascular endothelial growth factor, and that Axl/Akt/NF-κB signaling participates in this process. These results provide the cellular and molecular basis of MTA's anti-inflammatory action in clinical applications.

In Vivo Comparative Evaluation of Periapical Healing in Response to a Calcium Silicate and Calcium Hydroxide Based Endodontic Sealers

BACKGROUND:

The composition of the root canal filling materials together with the apical limit of the root canal obturation affect the complete periapical healing after root canal therapy.

AIM:

This study was performed to evaluate and compare the periapical healing in response to calcium-silicate (iRoot SP) and calcium-hydroxide (Apexit) based-sealers.

MATERIAL AND METHODS:

Seventy-two upper premolars root canals of six dogs were used. The teeth were randomly assigned to four groups: Group one: roots were obturated using gutta-percha and Apexit-sealer; Group two: roots were obturated using gutta-percha&iRoot SP-sealer; Group three: the teeth were left open without obturation; Group four: where healthy teeth were used as a negative control. Teeth were evaluated after one, two and three months. The newly formed mineralised apical tissue and the periapical inflammatory infiltrate of the obtained photomicrographs were evaluated, and scorings were statistically-analysed.

RESULTS:

The mean percentage of the periapical inflammatory infiltrates and mineralisation scoring after one, two and three months evaluation period were not significantly different among the four groups (P > 0.05).

CONCLUSIONS:

Regardless of the sealer used, iRoot SP and Apexit promote healing of periapical tissues. IRoot SP sealer showed early insignificant more partial and almost full healing after two and three months.

Influence of iRoot SP and mineral trioxide aggregate on the activation and polarization of macrophages induced by lipopolysaccharide

BACKGROUND

Biomaterials could affect the inflammation reaction and wound healing via the activation and polarization of macrophages. However, the influence of iRoot SP and mineral trioxide aggregate (MTA) on macrophage polarization under inflammatory conditions was not reported although these two root filling materials have been applied extensively in patients undergoing endodontic treatment. Therefore, the present study aimed to explore the mechanism how iRoot SP and MTA affect the cell behavior of RAW 264.7 macrophages when stimulated by lipopolysaccharide (LPS) in vitro.

METHODS

The gene expression of three main related pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) was examined by quantitative real-time polymerase chain reaction (qRT-PCR) in RAW 264.7 macrophages when stimulated by iRoot SP and MTA in the presence of LPS. The protein expression of the M1 and M2 phenotype specific markers, CD11c and CD206, was assessed by immunofluorescence and flow cytometry in RAW 264.7 macrophages.

RESULTS

LPS promoted the expression of IL-1β, TNF-α, and IL-6 in RAW 264.7 macrophages as compared to the control group. Both iRoot SP and MTA were significantly able to enhance the expression of IL-1β, TNF-α, and IL-6 in RAW 264.7 macrophages as compared to LPS group. LPS could increase the expression of CD11c as compared to the control group while iRoot SP and MTA were able to enhance the expression of both CD11c and CD206 as compared to LPS group.

CONCLUSIONS

iRoot SP and MTA could potentially promote the release of pro-inflammatory cytokines in RAW 264.7 macrophages and induce into M1/M2 phenotype when cultured with LPS.