Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

Cytotoxicity and genotoxicity of bioceramic root canal sealers compared to conventional resin-based sealer

The aim of this study was to evaluate cytotoxicity and genotoxicity of calcium-silicate based sealers and comparing them with a gold standard-an epoxy-based sealant. Two experimental cell lines were used, gingival fibroblasts (hGF) and monocyte/macrophage peripheral blood cell line (SC). The cytotoxicity (XTT assay) and genotoxicity (comet assay) were evaluated both after 24-h and 48-h incubation. Additionally, after 48-h incubation, the cell apoptosis and cell cycle progression was detected. BioRoot Flow induced a significant decrease in hGF cells viability compared to the negative control groups both after 24-h (p < 0.001) and 48-h incubation (p < 0.01). In group with SC cells, after 24-h incubation significant increase in cells viability was detected for AH Plus Bioceramic Sealer in comparison to negative control (p < 0.05). BioRoot Flow and BioRoot RCS can be considered potentially genotoxic for the hGF cells after 48-h incubation (> 20% DNA damage). BioRoot Flow and BioRoot RCS, may have potential genotoxic effects and induce apoptosis in hGF cells which may irritate periapical tissues, resulting in a delayed healing. The findings of the study would be useful in selection of an appropriate sealant for root canal filling without causing cytotoxicity and genotoxicity.

The Effects of Calcium Silicate- and Calcium Hydroxide-based Root Canal Sealers on Postoperative Pain: A Randomized Clinical Trial

INTRODUCTION

This study aimed to compare the postoperative pain level changes resulting from using calcium silicate- (EndoSeal MTA) and calcium hydroxide-based (Sealapex) root canal sealers in mandibular first and second molar teeth with symptomatic apical periodontitis.

METHODS

A total of 60 patients with symptomatic apical periodontitis in their lower molar teeth were randomly allocated into 2 groups according to sealer type (n = 30). Demographic data, including gender, age, and smoking habit, and preoperative pain measures were recorded. Root canal treatments were performed in a single visit. Postoperative pain measurements and analgesic intake were measured at 6, 12, 24, and 48 hours and after 3, 5, and 7 days using the visual analog scale. The data were statistically analyzed using a chi-squared test (to compare gender, age, smoking habit, analgesic intake, and sealer extrusion), the Mann-Whitney U test (to compare pain levels), Friedman tests (for the evaluations of the reduction in pain levels over time), and Spearman's correlation test (to analyze the relationships of age, gender, smoking habit factors with postoperative pain) (P = .05).

RESULTS

The statistical analysis showed no significant differences between the groups in postoperative pain and analgesic intake at any of the time intervals evaluated (P > .05).

CONCLUSIONS

Patients treated with calcium silicate- and calcium hydroxide-based root canal sealers experienced similar postoperative pain and no statistically significant differences were observed in analgesic intake.

Cytocompatibility and cell migration evaluation of calcium silicate-based root canal sealer compared to epoxide-amine resin sealer in stem cells from human apical papilla: An in-vitro study

The purpose of this study was to assess the effect of a calcium silicate-based sealers (CeraSeal) and an epoxy resin-based sealer (AH Plus) on cytotoxicity and cell migration of stem cell from the human apical papilla (hSCAPs) by using the Alamar Blue, Annexin V-FICT and wound healing assays. In Alamar Blue assay, hSCAPs exposed to undiluted CeraSeal extract had significantly higher cell viability compared with that observed when cells were treated with AH Plus in all experimental period (p < 0.001). The flow cytometry analysis confirmed the comparison on viable cells and indicated that AH Plus increased apoptosis compared to CeraSeal and the control groups (p < 0.001). Additionally, AH Plus exhibited significantly lower level of cell migration than CeraSeal and the control for up to 48 h observation (p < 0.01). In summary, calcium silicate-based sealer (CeraSeal) is less cytotoxic and more biocompatible than epoxy resin-based sealer (AH Plus).

TNF-α, IL-1B and IL-6 affect the differentiation ability of dental pulp stem cells

BACKGROUND

This in vitro study examined the effect of the inflammatory cytokines (tumour necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6) on osteogenic, chondrogenic, and adipogenic differentiation of dental pulp stem cells (DPSCs) which have significant relevance in future regenerative therapies.

METHODS

DPSCs were isolated from the impacted third molar dental pulp and determined with flow cytometry analysis. DPSCs were divided into into 5 main groups with 3 subdivisions for each group making a total of 15 groups. Experimental groups were stimulated with TNF-α, IL-1β, IL-6, and a combination of all three to undergo osteogenic, chondrogenic, and adipogenic differentiation protocols. Next, the differentiation of each group was examined with different staining procedures under a light microscope. Histological analysis of osteogenic, chondrogenic, and adipogenic differentiated pellets was assessed using a modified Bern score. Statistical significance determined using one-way analysis of variance, and correlations were assessed using Pearson's test (two-tailed).

RESULTS

Stimulation with inflammatory cytokines significantly inhibited the osteogenic, chondrogenic and adipogenic differentiation of DPSCs in terms of matrix and cell formation resulting in weak staining than the unstimulated groups with inflammatory cytokines. On contrary, the unstimulated groups of MSCs have shown to be highly proliferative ability in terms of osteogenic, chondrogenic, and adipogenic differentiation.

CONCLUSIONS

DPSCs have high osteogenic, chondrogenic, and adipogenic differentiation capabilities. Pretreatment with inflammatory cytokines decreases the differentiation ability in vitro, thus inhibiting tissue formation.

Cytotoxicity comparison of Bio C Sealer against multiple root canal sealers

Background

The aim of this study was to compare the cytotoxicity of calcium silicate-based endodontic sealer, Bio-C® Sealer, with other calcium silicate-based sealers: BioRoot™ RCS, one silicon-based sealer combined with calcium silicate particles: GuttaFlow® Bioseal, one resin MTA-based root canal sealer: MTA Fillapex®, and an epoxy resin-based sealer: AH Plus®.

Material and Methods

NIH 3T3 fibroblasts were cultured and sealers extracts were obtained. Cytotoxicity was evaluated by the MTS assay and the optical densities of the solutions were measured with a microplate reader. This study was designed with one sample for each control group and n=10 for each treatment group of the different sealants. The results were classified according to the degree of cell viability and underwent statistical analysis with the ANOVA test (p<0.05). The samples were examined under an inverted microscope to evaluate the effect of each sealer on fibroblast cell morphology.

Results

Cells incubated with GuttaFlow® Bioseal extract showed the highest cell viability without statistically significant differences with the control group. BioRoot™ RCS and Bio-C® Sealer showed moderate (tending to slight) cytotoxicity and both AH Plus® and MTA Fillapex® showed severe cytotoxicity in comparison with the control group (p<0.05). AH Plus® and MTA Fillapex® were not significantly different from one another; nor was BioRoot™ RCS from Bio-C® Sealer. Microscope examination found that fibroblasts in contact with GuttaFlow® Bioseal and Bio-C® Sealer presented the most similar aspects to the control group both in terms of number and shape.

Conclusions

Bio-C® Sealer showed moderate (tending to slight) cytotoxicity compared with the control group, GuttaFlow® Bioseal showed no cytotoxicity, BioRoot™ RCS moderate-slight cytotoxicity and AH Plus® and MTA Fillapex® severe cytotoxicity. Key words:Biocompatibility, calcium silicate-based endodontic sealers, cytotoxicity, endodontic sealer.

Antimicrobial Action, Genotoxicity, and Morphological Analysis of Three Calcium Silicate-Based Cements

This study is aimed at evaluating five mineral oxides (5MO), mineral trioxide aggregate repair high plasticity (MTA HP), and mineral trioxide aggregate (MTA) in relation to the antimicrobial action over Porphyromonas gingivalis, Porphyromonas endodontalis, Parvimonas micra, Fusobacterium nucleatum, and Prevotella intermedia; the genotoxicity over mouse macrophage (RAW 264.7) and osteoblast (Mg-63) cultures; and the morphological analysis using scanning electron microscopy (SEM) analysis (50 k and ×100 k). Sodium hypochlorite (NaOCl), calcium hydroxide, and saline solution were used as control groups in the different analysis. All data were submitted to a normality test and then analyzed with one-way ANOVA, Tukey, and Kruskal-Wallis and Dunn tests, considering α ≤ 0.05 significance level. It was found that over P. gingivalis and P. endodontalis, there was no a significant difference between the calcium silicate-based cements (CSC) and the control group of saline solution, and only 5MO was similar to the NaOCl group. However, over P. micra, all groups were effective and showed a statistically significant difference compared to the saline solution group. Conversely, none of the groups were effective over F. nucleatum and P. intermedia, except of the NaOCl group. There was a significant difference between 5MO and MTA groups in comparison with NaOCl and MTA HP over osteoblasts and macrophages after 24 hours. SEM images showed small irregular particles interspersed with some elongated needle-like particles and small irregular particles with some larger particles as well as elongated particles. It was concluded that 5MO, MTA, and MTA HP have effective antimicrobial action over P. micra. However, only 5MO is effective over P. gingivalis and P. endodontalis. Besides, 5MO and MTA are not genotoxic over mouse macrophage (RAW 264.7) and osteoblast (Mg-63) cultures.

The response of Mesenchymal Stem Cells to endodontic materials

An endodontic material must be minimally harmful to stem cells since they are essential, thanks to their capacity for cell proliferation, self-renewal, and differentiation. For this reason, in this in vitro study, the cell viability and the expression of genes involved in cell plasticity and differentiation were investigated in stem cells recovered from human dental pulp (hDPSCs) that were in contact with four endodontic materials (Endofill, MTA, Pulp Canal Sealer, and Sealer 26). The viability of HDPSCs was assessed by MTT and trypan blue exclusion assays. PCR evaluated cellular plasticity by determining the CD34, CD45, Nestin, CD105, Nanog, and OCT4 expressions. The effect on cell differentiation was determined by RT-PCR expression of the RUNX2, ALP, OC/BGLAP, and DMP1 genes. The data were analyzed using ANOVA with Bonferroni correction (p <0.05). Pulp Canal Sealer and Endofill decreased cell viability after 48 hours (p <0.001). MTA and Sealer 26 did not disrupt cell viability (p> 0.05). When cultivated in the presence of MTA and Sealer 26, hDPSCs expressed Nestin, CD105, NANOG, and OCT-4 and did not express CD34 and CD45. MTA and Sealer 26 interfered with DMP1, OC/BGLAP and RUNX2 expressions (p <0.05) but did not change ALP gene expression (p> 0.05). MTA and Sealer 26 showed biological compatibility in the presence of hDPSCs.

Cytotoxicity assessment of Bio-C Repair Íon+: A new calcium silicate-based cement

Background. Direct pulp capping is a method designed to preserve the exposed dental pulp. Due to good biological, physical, and mechanical properties, new versions of calcium silicate-based materials have been developed as pulp capping materials. The present study aimed to evaluate the cytotoxic effects of four calcium silicate-based pulp capping materials, of which the Bio-C Repair Íon+ is still in an experimental phase.

Methods. Biodentine, MTA Repair HP, Bio-C Repair, and Bio-C Repair Íon+ cements were dispensed in a metallic matrix to produce 125-mm³ specimens, which were immersed in Dulbecco’s Modified Eagle Medium (DMEM) to obtain extracts. NIH 3T3 cells were cultured and exposed to the extracts for 24 hours and seven days. Cell viability was assessed by the methyl tetrazolium test (MTT). The mean values for the experimental and control groups (without treatment) were compared by analysis of variance (ANOVA) and post hoc Tukey tests, considering a significance level of 5%.

Results. All the tested materials demonstrated a reduction in cell viability (P < 0.05). According to ISO 10993-5: 2009 (E), Bio-C Repair Íon+ exhibited mild and moderate cytotoxicity in the 24- hour and 7-day analyses, respectively. Bio-C Repair and Biodentine showed mild cytotoxicity, and MTA Repair HP exhibited moderate cytotoxicity at both intervals.

Conclusion. The highest cell viability was demonstrated by Biodentine, MTA, and Repair HP, in descending order. Bio-C Repair and Bio-C Repair Íon+ showed moderate cytotoxicity, similar to MTA Repair HP in the 7-day analysis.

Influence of human teeth matrix on the cellular and biological properties of dental pulp stem cells - An in vitro study

Background

A major challenge in bone tissue regeneration is the use of right combination of stem cells with osteoinductive biomaterials. Hence, the present in vitro study was aimed at evaluating the effect of mineralized teeth matrix (MTM) and demineralized teeth matrix (DTM) on the selected cellular and biological characteristics of human dental pulp stem cells (DPSCs).

Methods

Established DPSCs were cultured in conditioned media (CM) of MTM and DTM and analyzed on their morphology, proliferation rate, population doubling time (PDT), viability, migration ability, ploidy and expression of cell surface markers, Further, the effect of MTM and DTM on the biocompatibility and osteogenic differentiation ability of DPSCs was evaluated.

Results

The DPSCs exhibited a fibroblast-like morphology with >80% viability. Cells were highly proliferative with an average PDT of 61 ​± ​12 ​h. A greater proliferation of DPSCs in the scratched area was observed when cultured in CM of teeth matrix compared to the cells in basal media. Moreover, no chromosomal abnormalities were induced during the culture of DPSCs. Flow cytometry analysis showed that DPSCs in basal media and CM of MTM and DTM were positive for CD29, CD44, CD73, CD90 (>70%), and negative for CD34 and CD45 (<0.1%). Alizarin red staining showed the higher deposition of mineralized nodules in DPSCs cultured with DTM compared to MTM.

Conclusion

MTM and DTM-derived CM enhanced the proliferation and selected phenotypic markers expression with no chromosomal abnormalities in DPSCs. In addition, both matrices were biocompatible with DPSCs and increased the osteogenic differentiation through higher nodule formation.

Biological assessment of a new ready-to-use hydraulic sealer

Objectives

This study compared the cytotoxicity, biocompatibility, and tenascin immunolabeling of a new ready-to-use hydraulic sealer (Bio-C Sealer) with MTA-Fillapex and white MTA-Angelus.

Materials and Methods

L929 fibroblasts were cultivated and exposed to undiluted and diluted material extracts. Polyethylene tubes with or without (the control) the materials were implanted into the dorsa of rats. At 7 days and 30 days, the rats were euthanized, and the specimens were prepared for analysis; inflammation and immunolabeling were measured, and statistical analysis was performed (p < 0.05).

Results

MTA-Fillapex exhibited greater cytotoxicity than the other materials at all time points (p < 0.05). The undiluted Bio-C Sealer exhibited greater cytocompatibility at 6 and 48 hours than white MTA-Angelus, with higher cell viability than in the control (p < 0.05). White MTA-Angelus displayed higher cell viability than the control at 24 hours, and the one-half dilution displayed similar results at both 6 and 48 hours (p < 0.05). At 7 days and 30 days, the groups exhibited moderate inflammation with thick fibrous capsules and mild inflammation with thin fibrous capsules, respectively (p > 0.05). At 7 days, moderate to strong immunolabeling was observed (p > 0.05). After 30 days, the control and MTA-Fillapex groups exhibited strong immunolabeling, the white MTA-Angelus group exhibited moderate immunolabeling (p > 0.05), and the Bio-C Sealer group exhibited low-to-moderate immunolabeling, differing significantly from the control (p < 0.05).

Conclusions

Bio-C Sealer and white MTA-Angelus exhibited greater cytocompatibility than MTA-Fillapex; all materials displayed adequate biocompatibility and induced tenascin immunolabeling.

Cytotoxicity and Bioactivity of Mineral Trioxide Aggregate and Bioactive Endodontic Type Cements: A Systematic Review

Background

Knowledge of the cytotoxicity and bioactivity of endodontic materials may assist in understanding their ability to promote dental pulp stem cell activity and pulp healing in primary teeth.

Materials and methods

This systematic review was carried out by searching the electronic databases such as PubMed, Google Scholar, and Cochrane reviews for the articles published between January 2000 and December 2018 using the appropriate MeSH keywords. An independent investigator evaluated the abstracts and titles for possible inclusion, as per the stipulated inclusion and exclusion criteria. The topics considered for extracting data from each study were: cell lineage, cytotoxicity assay used, and type of material tested.

Results

Seven eligible studies were selected for assessing the quality of evidence on the bioactivity of bioactive endodontic cements (BECs) (1 human cell line, 2 animal cell lines, and 4 in vitro, animal, and human studies) and 13 studies were selected for reviewing the quality of evidence on cytotoxicity (7 human cell lines, 4 animal cell lines, and 2 animal model studies). Very limited studies had been conducted on the bioactivity of materials other than mineral trioxide aggregate (MTA). With regards to cytotoxicity, the studies were diverse and most of the studies were based on MTT assay. Mineral trioxide aggregate is the most frequently used as well as studied root-end filling cement, and the literature evidence corroborated its reduced cytotoxicity and enhanced bioavailability.

Conclusion

There was a lack of sufficient evidence to arrive at a consensus on the ideal material with minimal cytotoxicity and optimal bioactivity. More focused human/cell line-based studies are needed on the available root filling materials.

Clinical significance

The present systematic review provides an update on the available literature evidence on the cytotoxicity and bioactivity of various BECs including MTAs and their influence on the different cells with respect to their composition and strength.

How to cite this article

Maru V, Dixit U, Patil RSB, et al. Cytotoxicity and Bioactivity of Mineral Trioxide Aggregate and Bioactive Endodontic Type Cements: A Systematic Review. Int J Clin Pediatr Dent 2021;14(1):30–39.

The Effect of Selected Dental Materials Used in Conservative Dentistry, Endodontics, Surgery, and Orthodontics as Well as during the Periodontal Treatment on the Redox Balance in the Oral Cavity

Oxidative stress (OS) is a redox homeostasis disorder that results in oxidation of cell components and thus disturbs cell metabolism. OS is induced by numerous internal as well as external factors. According to recent studies, dental treatment may also be one of them. The aim of our work was to assess the effect of dental treatment on the redox balance of the oral cavity. We reviewed literature available in PubMed, Medline, and Scopus databases, including the results from 2010 to 2020. Publications were searched according to the keywords: oxidative stress and dental monomers; oxidative stress and amalgam; oxidative stress and periodontitis, oxidative stress and braces, oxidative stress and titanium; oxidative stress and dental implants, oxidative stress and endodontics treatment, oxidative stress and dental treatment; and oxidative stress and dental composite. It was found that dental treatment with the use of composites, amalgams, glass-ionomers, materials for root canal filling/rinsing, orthodontic braces (made of various metal alloys), titanium implants, or whitening agents can disturb oral redox homeostasis by affecting the antioxidant barrier and increasing oxidative damage to salivary proteins, lipids, and DNA. Abnormal saliva secretion/composition was also observed in dental patients in the course of OS. It is suggested that the addition of antioxidants to dental materials or antioxidant therapy applied during dental treatment could protect the patient against harmful effects of OS in the oral cavity.

Comparison of Biocompatibility of Calcium Silicate-Based Sealers and Epoxy Resin-Based Sealer on Human Periodontal Ligament Stem Cells

The aim of this study was to evaluate the biocompatibility of calcium silicate-based sealers (CeraSeal and EndoSeal TCS) and epoxy resin-based sealer (AH-Plus) in terms of cell viability, inflammatory response, expression of mesenchymal phenotype, osteogenic potential, cell attachment, and morphology, of human periodontal ligament stem cells (hPDLSCs). hPDLSCs were acquired from the premolars (n = 4) of four subjects, whose ages extended from 16 to 24 years of age. Flow cytometry analysis showed stemness of hPDLSCs was maintained in all materials. In cell viability test, AH-Plus showed the lowest cell viability, and CeraSeal showed significantly higher cell viability than others. In ELISA test, AH-Plus showed higher expression of IL-6 and IL-8 than calcium silicate-based sealers. In an osteogenic potential test, AH-Plus showed a lower expression level than other material; however, EndoSeal TCS showed a better expression level than others. All experiments were repeated at least three times per cell line. Scanning electronic microscopy studies showed low degree of cell proliferation on AH-Plus, and high degree of cell proliferation on calcium silicate-based sealers. In this study, calcium silicate-based sealers appear to be more biocompatible and less cytotoxic than epoxy-resin based sealers.

Genotoxicity of root canal sealers: a literature review

OBJECTIVES

Root canal sealers are widely used worldwide in endodontics to prevent reinfection and growth of surviving microorganisms. Considering the strong correlation between genetic damage and carcinogenesis, evaluation of genotoxicity induced by endodontic sealers is recommended for elucidating the true health risks to patients and professionals. The purpose of this article was to provide a comprehensive review of studies involving genotoxicity analysis of endodontic sealers and the used methodologies.

MATERIALS AND METHODS

A literature search was made in PubMed using the following combination of words "genotoxicity," "mutagenicity," "endodontic sealers," and "root canal sealers." A total of 39 articles with genotoxicity studies were selected for the present study.

RESULTS

Sealers have been ranked in decreasing order of their genotoxicity as: ZOE sealers > GIC sealers > S sealers > ER sealers > MR sealers > Novel sealers > CH sealers > CS sealers.

CONCLUSIONS

All published data showed some evidence of genotoxicity for most of the commercial root canal sealers; however, contradictory results were found, mainly for AH Plus, the most studied sealer.

CLINICAL RELEVANCE

The information provided would direct the endodontists to use the less genotoxic materials in endodontic treatment in a way to reduce DNA damage promoting oral healthcare.

Biological Effects of Tricalcium Silicate Nanoparticle-Containing Cement on Stem Cells from Human Exfoliated Deciduous Teeth

Nanomaterials can enhance interactions with stem cells for tissue regeneration. This study aimed to investigate the biological effects of tricalcium silicate nanoparticle-containing cement (Biodentine™) during or after setting on stem cells from human exfoliated deciduous teeth (SHED) to mimic clinically relevant situations in which materials are adapted. Specimens were divided into four groups depending on the start of extraction time (during (3, 6 and 12 min) or after setting (24 h)) and extracted in culture medium for 24 h for further physicochemical and biological analysis. After cell viability in serially diluted extracts was evaluated, odontogenic differentiation on SHED was evaluated by ARS staining using nontoxic conditions. A physicochemical analysis of extracts or specimens indicated different Ca ion content, pH, and surface chemistry among groups, supporting the possibility of different biological functionalities depending on the extraction starting conditions. Compared to the 'after setting' group, all 'during setting' groups showed cytotoxicity on SHED. The during setting groups induced more odontogenic differentiation at the nontoxic concentrations compared to the control. Thus, under clinically simulated extract conditions at nontoxic concentrations, Biodentine™ seemed to be a promising odontoblast differentiating biomaterial that is helpful for dental tissue regeneration. In addition, to simulate clinical situations when nanoparticle-containing cement is adjusted, biological effects during setting need to be considered.

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.

Cytocompatibility and cell proliferation evaluation of calcium phosphate-based root canal sealers

Objectives

This study aimed to evaluate the cell viability and migration of Endosequence Bioceramic Root Canal Sealer (BC Sealer) compared to MTA Fillapex and AH Plus.

Materials and Methods

BC Sealer, MTA Fillapex, and AH Plus were placed in contact with culture medium to obtain sealers extracts in dilution 1:1, 1:2 and 1:4. 3T3 cells were plated and exposed to the extracts. Cell viability and migration were assessed by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and Scratch assay, respectively. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05).

Results

The MTT assay revealed greater cytotoxicity for AH Plus and MTA Fillapex at 1:1 dilution when compared to control (p < 0.05). At 1:2 and 1:4 dilutions, all sealers were similar to control (p > 0.05) and MTA Fillapex was more cytotoxic than BC Sealer (p < 0.05). Scratch assay demonstrated the continuous closure of the wound according to time. At 30 hours, the control group presented closure of the wound (p < 0.05). At 36 hours, only BC Sealer presented the closure when compared to AH Plus and MTA Fillapex (p < 0.05). At 42 hours, AH Plus and MTA Fillapex showed a wound healing (p > 0.05).

Conclusions

All tested sealers demonstrated cell viability highlighting BC Sealer, which showed increased cell migration capacity suggesting that this sealer may achieve better tissue repair when compared to other tested sealers.

Depth-Dependent Cellular Response from Dental Bulk-Fill Resins in Human Dental Pulp Stem Cells

The proper choice of dental composite resins is necessary based on the minimal cytotoxicity and antiodontogenesis on human dental pulp stem cells for dental pulp-dentin tissue repair and regeneration. The aim of this study was to evaluate the cytotoxicity and antidifferentiation effects of dental bulk-fill resins, able to be polymerized as a bulk status for filling deep cavity of a tooth by single light curing, against human dental pulp stem cells (hDPSCs) from three compartments corresponding to depth (0-2, 2-4, and 4-6 mm) from the light-curing site. Three bulk-fill composite resins (SDR, Venus bulk-fill (VBF), and Beautifil Bulk Flowable (BBF)) and a conventional flowable composite resin (Filtek Z350 XT flowable restorative (ZFF)) were individually filled into a cylindrical hole (h = 2 mm, Ф = 10 mm), and three compartments (total ~6 mm of height) were combined as a single assembly for light curing. The resin samples from the three layers were separated and eluted in the culture medium. The extracts were exposed to hDPSCs, and cytotoxicity and differentiation capability were evaluated. Depth of cure and surface hardness according to depth were determined. All bulk-fill resins except BBF revealed cytotoxicity from 4 to 6 or 2 to 4 mm, while ZFF was cytotoxic at over 2 mm. Depth of cure was detected from 3.55 to 4.02 mm in the bulk-fill resins (vs. ~2.25 mm in conventional resin), and 80% hardness compared with that of a fully polymerized top surface was determined from 4.2 to 6 mm in the bulk-fill resin (vs. 2.4 mm in conventional resin). Antidifferentiation was revealed at a depth of 4-6 mm in the bulk-fill resin. There was a difference in depth of cytotoxicity and antidifferentiation between the bulk-fill composite resins, which was mainly due to different cure depths and ingredients. Therefore, careful consideration of choice of bulk-fill resins is necessary especially for restoration of deep cavities for maintaining the viability and differentiation ability of dental pulp stem cells.

In Vitro Comparison of Biocompatibility of Calcium Silicate-Based Root Canal Sealers

The aim of this study was to assess the effect of three calcium silicate-based sealers (EndoSeal MTA, Nano-ceramic Sealer, and Wellroot ST) and two epoxy resin-based sealers (AH-Plus, AD Seal) on various aspects, such as cell viability, inflammatory response, and osteogenic potential, of human periodontal ligament stem cells (hPDLSCs). AH-Plus showed the lowest cell viability on hPDLSCs in all time periods in fresh media. In set media, hPDLSCs showed no significant differences in cell viability among all the tested materials. Wellroot ST showed the highest level of cell adhesion and the morphology of attached cells. AH-plus presented a significantly higher expression of IL-6 and IL-8 than the other sealers. AD Seal and three calcium silicate sealers showed high expression of the mesenchymal stem cell markers. ALP mRNA expression showed a significant increase in time-dependent manner on all of three calcium silicate-based sealers, which do not seem to interfere with the differentiation of hPDLSCs into osteoblasts. Based on the results from this study, calcium silicate-based sealers appear to be more biocompatible and less cytotoxic than epoxy resin-based sealers. Meanwhile, further and long-term clinical follow-up studies are required.

Tricalcium silicate cements: osteogenic and angiogenic responses of human bone marrow stem cells

Tricalcium silicate cements (TSCs) are used in endodontic procedures to promote wound healing and hard tissue formation. The aim of this study was to evaluate and compare the effect of commonly used TSCs [mineral trioxide aggregate (MTA), Biodentine, and TotalFill] on cellular metabolism and osteogenic/angiogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) in vitro. We tested the null hypothesis of no difference between MTA, Biodentine, and TotalFill in stem cell responses. Cells were subjected to eluates of the tested materials for up to 14 d. Cell viability was evaluated using the 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Real-time PCR was used to determine the levels of expression of the osteogenic factors alkaline phosphatase (ALP), osteoprotegerin (OPG), osteocalcin (OC), and collagen 1A (COL1A1), and the angiogenic factors vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 1 (FGF1). ELISAs were used to measure the levels of VEGFA and ALP in culture supernatants. Mineralization in vitro of hBMSCs was assessed using Alizarin Red staining. The hBMSCs tolerated exposure to TSCs well, with Biodentine showing the most favorable effect on cell viability. Expression of ALP, COL1A1, OPG, and VEGFA were differentially affected by the materials, with Biodentine and TotalFill inducing earlier changes at gene level. Increased mineralization was observed with time, after exposure to all TSCs tested, with MTA showing the greatest effect. The results revealed different responses of hBMSCs to TSCs in vitro.

Cytotoxicity of Two Experimental Epoxy Resin-Based Sealers

INTRODUCTION

Many endodontic sealers are available, but search for the ideal sealer continues. This study aimed to assess the cytotoxicity of two experimental endodontic sealers in comparison with AH-26 resin sealer.

METHODS AND MATERIALS

This in vitro study was conducted on conventional and experimental root canal sealers: AH-26, an epoxy resin experimental sealer A (ES-A) composed of calcium tungstate, zirconium oxide, aerosil, bismuth oxide, titanium oxide, hexamine and an epoxy resin and experimental sealer B (ES-B) with compositions similar to ES-A except for the presence of imidazoline as a catalyst. The experimental sealers containing nano-particles were mixed with 37.5% of an epoxy resin. The extraction of five samples of each experimental sealer (A, B) and AH-26 sealer were subjected to MTT assay in the form of set and fresh at 1, 24 and 72 h with 1, 10, 100% dilution according to the International Standard ISO:10993-2012. Data were analyzed using the one-way ANOVA.

RESULTS

The set ES-A had the least cytotoxicity from the first hour but the cytotoxicity of ES-B and AH-26 extraction decreased over time. In fresh form, except for 100% concentration, ES-A showed the least cytotoxicity compared to the other two sealers.

CONCLUSION

All three sealers had high cytotoxicity in 100% concentration but had low cytotoxicity in 10% and 1% concentrations.

Mineral Trioxide Aggregate-A Review of Properties and Testing Methodologies

Mineral trioxide aggregate (MTA) restoratives and MTA sealers are commonly used in endodontics. Commonly referenced standards for testing of MTA are ISO 6876, 9917-1 and 10993. A PubMed search was performed relating to the relevant tests within each ISO and "mineral trioxide aggregate". MTA restoratives are typically tested with a mixture of tests from multiple standards. As the setting of MTA is dependent upon hydration, the results of various MTA restoratives and sealers are dependent upon the curing methodology. This includes physical properties after mixing, physical properties after setting and biocompatibility. The tests of flow, film thickness, working time and setting time can be superseded by rheology as it details how MTA hydrates. Physical property tests should replicate physiological conditions, i.e. 37 °C and submerged in physiological solution. Biocompatibility tests should involve immediate placement of samples immediately after mixing rather than being cured prior to placement as this does not replicate clinical usage. Biocompatibility tests should seek to replicate physiological conditions with MTA tested immediately after mixing.