Human dental pulp cells response to mineral trioxide aggregate (MTA) and MTA Plus: cytotoxicity and gene expression analysis

Anti-inflammatory cerium-containing nano-scaled mesoporous bioactive glass for promoting regenerative capability of dental pulp cells

AIMS

This study aimed to investigate the anti-inflammatory and odontoblastic effects of cerium-containing mesoporous bioactive glass nanoparticles (Ce-MBGNs) on dental pulp cells as novel pulp-capping agents.

METHODOLOGY

Ce-MBGNs were synthesized using a post-impregnation strategy based on the antioxidant properties of Ce ions and proposed the first use of Ce-MBGNs for pulp-capping application. The biocompatibility of Ce-MBGNs was analysed using the CCK-8 assay and apoptosis detection. Additionally, the reactive oxygen species (ROS) scavenging ability of Ce-MBGNs was measured using the 2,7-Dichlorofuorescin Diacetate (DCFH-DA) probe. The anti-inflammatory effect of Ce-MBGNs on THP-1 cells was further investigated using flow cytometry and quantitative real-time polymerase chain reaction (RT-qPCR). Moreover, the effect of Ce-MBGNs on the odontoblastic differentiation of the dental pulp cells (DPCs) was assessed by combined scratch assays, RT-qPCR, western blotting, immunocytochemistry, Alizarin Red S staining and tissue-nonspecific alkaline phosphatase staining. Analytically, the secretions of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were detected with enzyme-linked immunosorbent assay (ELISA).

RESULTS

Ce-MBGNs were confirmed to effectively scavenge ROS in THP-1-derived macrophages and DPCs. Flow cytometry and RT-qPCR assays revealed that Ce-MBGNs significantly inhibited the M1 polarization of macrophages (Mφ). Furthermore, the protein levels of TNF-α and IL-1β were downregulated in THP-1-derived macrophages after stimulation with Ce-MBGNs. With a step-forward virtue of promoting the odontoblastic differentiation of DPCs, we further confirmed that Ce-MBGNs could regulate the formation of a conductive immune microenvironment with respect to tissue repair in DPCs, which was mediated by macrophages.

CONCLUSIONS

Ce-MBGNs protected cells from self-produced oxidative damage and exhibited excellent immunomodulatory and odontoblastic differentiation effects on DPCs. As a pulp-capping agent, this novel biomaterial can exert anti-inflammatory effects and promote restorative dentine regeneration in clinical treatment. We believe that this study will stimulate further correlative research on the development of advanced pulp-capping agents.

"Biological responses of two calcium-silicate-based cements on a tissue-engineered 3D organotypic deciduous pulp analogue"

OBJECTIVES

The biological responses of MTA and Biodentine™ has been assessed on a three-dimensional, tissue-engineered organotypic deciduous pulp analogue.

METHODS

Human endothelial (HUVEC) and dental mesenchymal stem cells (SHED) at a ratio of 3:1, were incorporated into a collagen I/fibrin hydrogel; succeeding Biodentine™ and MTA cylindrical specimens were placed in direct contact with the pulp analogue 48 h later. Cell viability/proliferation and morphology were evaluated through live/dead staining, MTT assay and Scanning Electron Microscopy (SEM), and expression of angiogenic, odontogenic markers through real time PCR.

RESULTS

Viable cells dominated at day 3 after treatment presenting typical morphology, firmly attached within the hydrogel structures, as shown by live/dead staining and SEM images. MTT assay at day 1 presented a significant increase of cell proliferation in Biodentine™ group. Real-time PCR showed significant upregulation of odontogenic markers DSPP, BMP-2 (day 3,6), RUNX2, ALP (day 3) in contact with Biodentine™ compared to MTA and the control, whereas MTA promoted significant upregulation of DSPP, BMP-2, RUNX2, Osterix (day 3) and ALP (day 6) compared to the control. MSX1 presented downregulation in both experimental groups. Expression of angiogenic markers VEGFa and ANGPT-1 at day 3 was significantly upregulated in contact with Biodentine™ and MTA respectively, while the receptors VEGFR1, VEGFR2 and Tie-2, as well as PECAM-1 were downregulated.

SIGNIFICANCE

Both calcium silicate-based materials are biocompatible and exert positive angiogenic and odontogenic effects, although Biodentine™ during the first days of culture, seems to induce higher cell proliferation and provoke a more profound odontogenic and angiogenic response from SHED.

Biocompatibility and Cytotoxicity of Pulp-Capping Materials on DPSCs, With Marker mRNA Expressions

OBJECTIVES

The present study aimed to (1) investigate biocompatibility and cytotoxicity of pulp-capping materials on viability of human dental pulp stem cells (hDPSCs); (2) determine angiogenic, odontogenic, and osteogenic marker mRNA expressions; and (3) observe changes in surface morphology of the hDPSCs using scanning electron microscopy (SEM).

METHODS

Impacted third molars were used to isolate the hDPSCs, which were treated with extract-release fluids of the pulp-capping materials (Harvard BioCal-Cap, NeoPUTTY MTA, TheraCal LC, and Dycal). Effects of the capping materials on cell viability were assessed using 3-(4,5-di-methyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium (MTS) assay and the apoptotic/necrotic cell ratios and reactive oxygen species (ROS) levels from flow cytometry. Marker expressions (alkaline phosphatase [ALP], osteocalcin [OCN], collagen type I alpha 1 [Col1A], secreted protein acidic and rich in cysteine [SPARC], osteonectin [ON], and vascular endothelial growth factor [VEGF]) were determined by quantitative reverse-transcription polymerase chain reaction. Changes in surface morphology of the hDPSCs were visualised by SEM.

RESULTS

The MTS assay results at days 1, 3, 5, and 7 indicated that Harvard BioCal-Cap, NeoPUTTY MTA, and TheraCal LC did not adversely affect cell viability when compared with the control group. According to the MTS assay results at day 14, no significant difference was found amongst Dycal, Harvard BioCal-Cap, NeoPUTTY MTA, and TheraCal LC affecting cell viability. Dycal was the only capping material that increased ROS level. High levels of VEGF expression were observed with Harvard BioCal-Cap, TheraCal LC, and NeoPUTTY MTA. NeoPUTTY MTA, and Dycal upregulated OCN expression, whereas TheraCal LC upregulated Col1A and SPARC expression. Only Dycal increased ALP expression. HDSCs were visualized in characteristic spindle morphology on SEM when treated with TheraCal LC and Harvard BioCal-Cap.

CONCLUSIONS

NeoPUTTY MTA and Harvard BioCal-Cap showed suitable biocompatibility values; in particular, these pulp-capping materials were observed to support the angiogenic marker.

Histological evaluation of tissue reaction and new bone formation of different calcium silicate-based cements in rats

BACKGROUND

The purpose of this study was to evaluate the local reactions and new bone formation of rat subcutaneous and bone tissue to different calcium silicate cements.

METHODS

In this study, 80 rats were divided into five groups as control, BIOfactor MTA (BIO), NeoMTA Plus (NEO), MTA Repair Hp (REP), Biodentine (DENT) and then into two subgroups according to sacrification times (7, 30 days; n = 8). Polyethylene tubes filled with appropriate materials (test groups); empty tubes (control group) were implanted into the dorsum of each rat subcutaneously. For intraosseous implantation, materials were placed in the cavities created in tibia of rats. Subcutaneous tissue and tibia samples were stained with haematoxylin-eosin and subjected to histopathological analysis. A score (0-3) was used to grade inflammatory reaction and new bone formation. Data were analysed by Kruskal-Wallis and Mann-Whitney U tests (P < 0.05).

RESULTS

Inflammatory reaction observed in subcutaneous and intraosseous tissues for 7 days decreased significantly in all groups over time (P < 0.05). It was determined that there was significant increase in new bone formation in REP, BIO, DENT groups over time (P < 0.05).

CONCLUSION

Four contemporary bioceramic materials induced local inflammation and tissues changes shortly after subcutaneous implantation, which were reduced over time. In ıntraosseous implantation, all materials induced new bone formation over time.

REGISTRATION NUMBER

ADJ-03-23-0134. © 2023 Australian Dental Association.

Injectable CNPs/DMP1-loaded self-assembly hydrogel regulating inflammation of dental pulp stem cells for dentin regeneration

Vital pulp preservation, which is a clinical challenge of aseptic or iatrogenic accidental exposure of the pulp, in cases direct pulp capping is the main technology. Human dental pulp stem cells (hDPSCs) play a critical role in pulp tissue repair, but their differentiative ability could be inhibited by the potential infection and inflammatory response of the exposed pulp. Therefore, inflammatory regulation and differentiated promotion of hDPSCs are both essential for preserving living pulp teeth. In this study, we constructed a functional dental pulp-capping hydrogel by loading cerium oxide nanoparticles (CNPs) and dentin matrix protein-1 (DMP1) into an injectable Fmoc-triphenylalanine hydrogel (Fmoc-phe3 hydrogel) as CNPs/DMP1/Hydrogel for in situ drugs delivery. With a view to long-term storage and release of CNPs (anti-inflammatory and antioxidant) to regulate the local inflammatory environment and DMP1 to promote the regeneration of dentin. Results of CCK-8, LDH release, hemolysis, and Live/Dead assessment of cells demonstrated the good biocompatibility of CNPs/DMP1/Hydrogel. The levels of alkaline phosphatase activity, quantification of the mineralized nodules, expressions of osteogenic genes and proteins demonstrated CNPs/DMP1/Hydrogel could protect the activity of hDPSCs' osteogenic/dentinogenic differentiation by reducing the inflammation response via releasing CNPs. The therapy effects were further confirmed in rat models, CNPs/DMP1/Hydrogel reduced the necrosis rate of damaged pulp and promoted injured pulp repair and reparative dentin formation with preserved vital pulps. In summary, the CNPs/DMP1/Hydrogel composite is an up-and-coming pulp-capping material candidate to induce reparative dentin formation, as well as provide a theoretical and experimental basis for developing pulp-capping materials.

Evaluation of the genotoxicity, cytotoxicity, and bioactivity of calcium silicate-based cements

BACKGROUND

As calcium silicate-based cements (CSCs) have found success in various vital pulp therapy applications, several new CSC products have emerged. This study aimed to assess the genotoxicity, cytotoxicity, and bioactivity of four CSCs by comparing the newly introduced materials Bio MTA+ and MTA Cem with previously studied materials, Biodentine and NeoMTA.

METHODS

Genotoxicity was evaluated using the micronucleus (MN) assay in human peripheral blood lymphocyte cells, measuring MN frequency and nuclear division index (NDI). Cytotoxicity was assessed in human dental pulp stem cells through the Water-Soluble Tetrazolium Salt-1 (WST-1) colorimetric assay. Bioactivity was determined by ELISA, measuring the levels of angiogenic and odontogenic markers (BMP-2, FGF-2, VEGF, and ALP). Statistical analyses included ANOVA, Dunnet and Sidak tests, and Wald chi-square test. (p < .05).

RESULTS

The MN frequency in the groups was significantly lower than that in the positive control group (tetraconazole) (p < .05). NDI values decreased with increasing concentration (p < .05). Bio MTA+ and NeoMTA showed decreased cell viability at all concentrations in 7-day cultures (p < .01). All materials increased BMP-2, FGF-2, and VEGF levels, with Biodentine and NeoMTA showing the highest levels of BMP-2 and FGF-2 on day 7. Biodentine displayed the highest VEGF levels on day 7. Biodentine and NeoMTA groups exhibited significantly higher ALP activity than the Bio MTA+ and MTA Cem groups by day 7.

CONCLUSION

Bio MTA+ and MTA Cem demonstrated no genotoxic or cytotoxic effects. Moreover, this study revealed bioactive potentials of Bio MTA+ and MTA Cem by enhancing the expression of angiogenic and osteogenic growth factors.

The Cytotoxic Assessment of Antibacterial-Enhanced Mineral Trioxide Aggregate Compared to Commercially Available Bioceramic Cements by Using Methyl-Thiazoldiphenyl-Tetrazolium (MTT) Assay on Human Dental Pulp Stem Cells: An In Vitro Study

Background and objective Preserving the vitality of the tooth is of prime significance during therapies such as direct pulp capping and pulpotomy that promote tertiary dentine formation and healing of pulp stumps. Procedures like apexogenesis and apexification also stimulate dentin and bone formation for root growth and closure. Conventional mineral trioxide aggregate (MTA) has good biocompatible and physical properties like longer setting time, presence of a cytotoxic component, i.e., tricalcium aluminate (TCA), moderate compressive strength, and moderate antimicrobial activity. Eliminating TCA and the addition of antibacterial components would improve the properties of the cement. In this study, we aimed to assess the cytotoxicity of MTA Angelus, Biodentine, and two antibacterial-enhanced MTAs by using methyl-thiazoldiphenyl-tetrazolium (MTT) assay. Materials and methods Human dental pulp was extirpated from extracted third molars, and human dental pulp stem cells (HDPSCs) were isolated and characterized by flow cytometry. HDPSCs were treated with MTA, Biodentine, or two antibacterial-enhanced MTAs depending on the study group. The control group constituted the untreated HDPSCs. The cell viability of HDPSCs was assessed using an MTT assay on days one, three, and seven. Results Varied levels of cytotoxicity were noticed at different time periods assessed using the tested materials, which was statistically significant (p=0.01). At all time periods assessed, the highest cell viability was noticed with Biodentine (88.7% on the first day, 80.4% on the third day, and 91.8% on the seventh day). Antibacterial-enhanced MTAs, either added with metronidazole or doxycycline, had more mean viable cells compared to conventional MTA on the third and seventh day (p=0.043 and 0.018 respectively). Conclusion Antibacterial-enhanced MTAs showed reduced cytotoxic properties when compared to conventional MTA. Biodentine was associated with the highest cell viability at all time periods.

Chitosan (CS)/Hydroxyapatite (HA)/Tricalcium Phosphate (β-TCP)-Based Composites as a Potential Material for Pulp Tissue Regeneration

This research focused on developing new materials for endodontic treatments to restore tissues affected by infectious or inflammatory processes. Three materials were studied, namely tricalcium phosphate β-hydroxyapatite (β-TCP), commercial and natural hydroxyapatite (HA), and chitosan (CS), in different proportions. The chemical characterization using infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the composition of the composite. Scanning electron microscopy (SEM) demonstrated that the design and origin of the HA, whether natural or commercial, did not affect the morphology of the composites. In vitro studies using Artemia salina (A. salina) indicated that all three experimental materials were biocompatible after 24 h, with no significant differences in mortality rate observed among the groups. The subdermal implantation of the materials in block form exhibited biocompatibility and biodegradability after 30 and 60 days, with the larger particles undergoing fragmentation and connective tissue formation consisting of collagen type III fibers, blood vessels, and inflammatory cells. The implanted material continued to undergo resorption during this process. The results obtained in this research contribute to developing endodontic technologies for tissue recovery and regeneration.

Effects of a mineralization-promoting peptide on the physical and chemical properties of mineral trioxide aggregate

Mineral trioxide aggregate (MTA) has been used widely in dentistry due to its sealing ability and biocompatibility. Delayed setting time is one of the major limitations of MTA. Various additives have been studied to further improve the properties of MTA with varied degrees of success. In this study, we have investigated the effect of a calcium phosphate mineralization promoting-peptide (MPP3) on the physical and chemical properties of MTA in comparison with Na₂HPO₄. Based on the reported effects of MPP3 on calcium-phosphate mineralization reaction, our hypothesis was that MPP3 may also show beneficial effects on the calcium-silicate mineralization system of MTA. Na₂HPO₄ was used for comparison since its setting accelerant effect on MTA has been well documented. The cements were prepared by mixing with distilled water, 0.40 mM MPP3 solution, 15% Na₂HPO₄ solution, and a combination of MPP3 and Na₂HPO₄ solution. Initial and final setting times were measured via Vicat needle. Microhardness values were measured via Vickers indenter at 1,3,7, and 28 days after hydration. Compressive strength after setting was measured via universal testing machine. Morphological and compositional analyses were performed via FESEM imaging, XRD and Raman spectroscopy. The microhardness data was evaluated via repeated-measures ANOVA. Setting time and compressive strength data were evasluated via one-way ANOVA. Initial setting time was reduced to ∼3 min in the Na₂HPO₄ containing groups but remained at ∼5 min in the control and MPP3 groups. Final setting times were significantly reduced in all groups compared to the control group. The reduction in the final setting times in the Na₂HPO₄ containing groups were significantly higher compared to the MPP3 group. Microhardness was significantly higher in the MPP3 group at all time points. No statistically significant difference in compressive strength was observed among the groups. FESEM analysis showed presence of ettringite crystals in the MPP3 group, and NaBiO₃ crystals in the Na₂HPO₄ containing groups. XRD analysis showed a broadening of peaks at 2θ = 32° in the Na₂HPO₄ containing groups, possibly due to presence of NaBiO₃. Raman spectroscopy showed statistically higher ettringite content in the MPP3 containing groups. Our findings indicate that MPP3 is a beneficial additive to eliminate some of the drawbacks associated with MTA with no detrimental effects on mechanical properties and without resulting in phases that potentially cause discoloration, such as NaBiO₃. We propose that the reduced final setting time and increased microhardness by MPP3 may be associated with the increased ettringite content. Future studies, where wider range of MPP3 concentrations are studied may help elucidate and optimize the beneficial effects of MPP3 observed in this study.

Survival analysis of pulpectomy in primary molars performed under dental general anaesthesia: a two-year retrospective study

BACKGROUND

To retrospectively investigate the success rate of primary-molar pulpectomy performed under general anaesthesia and the potential risk factors that affect the 24-month success rate.

METHODS

The case data and two-year follow-up records of children (aged 3-6 years) who received pulpectomy in primary molars performed under general anaesthesia were reviewed and assessed. Potential risk factors included age, gender, decayed-missing-filled teeth, endodontic diagnosis, tooth location, and postobturation sealing of the pulp chamber floor with MTA. With a two-year follow-up period, the outcomes of all the primary molars were classified into success and failure. Survival analysis was used to assess the outcomes. The Kaplan-Meier method was used to analyse the success rate. Univariate and multivariate Cox proportional hazards regression models were used to evaluate the potential risk factors associated with the overall survival of primary molars.

RESULTS

A total of 410 teeth from 163 children (88 boys and 75 girls) were included in this study. The overall two-year success rate was 66.1% for all primary molars. The mean overall survival time for this study was 22.1 (95% CI, 21.73‒22.48) months. Multivariate Cox regression analysis demonstrated that endodontic diagnosis (irreversible pulpitis or periapical periodontitis), tooth location (maxillary or mandibular primary molar), and postobturation sealing of the pulp chamber floor (MTA or no-MTA) were significant risk factors for overall survival in this study (P < .05). The differences in success rates were not statistically significant in terms of age, gender, and decayed-missing-filled teeth (P > .05).

CONCLUSIONS

When compared to teeth diagnosed with irreversible pulpitis, those with periapical periodontitis failed more frequently. Postobturation sealing of the pulp chamber floor with MTA improved the success rate of pulpectomy in primary molars, especially when the inflammation did not spread to the periradicular area.

Alkalizing Properties of Six Calcium-Silicate Endodontic Biomaterials

INTRODUCTION

Calcium silicate-based cements (CSC), are self-setting hydraulic biomaterials widely used for reparative procedures in dentistry and endodontics. These materials possess physical properties, such as ion release, porosity, solubility, and radiopacity. Their biological properties are connected to their alkalizing activity and calcium release capacity.

MATERIALS AND METHODS

Six calcium silicate-based materials were selected for this study: TheraCal LC (Bisco Inc., Schaumburg, IL, USA), MTA Plus (PrevestDenpro, Jammu, India Avalon Biomed Inc., Bradenton, FL, USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), RetroMTA (BioMTA, Seoul, Korea), MTA Flow (Ultradent Products, Inc., South Jordan, UT, USA), and OrthoMTA (BioMTA, Seoul, Korea). The pH was analyzed immediately after immersion (baseline) and after 1 h, 3 h, 1 day, 2 days, 3 days, 1 week, 2 weeks, 3 weeks, and 1 year with a pH meter, previously calibrated with solutions of known pH. All testing materials had alkaline pH.

RESULTS

Analysis of the tested materials showed statistically significant differences in terms of pH changes as a function of the time showed a gradual rise in the pH of all materials.

CONCLUSIONS

All tested materials exhibited continuous hydroxyl ion release resulting in a rise in pH until the end of time of experience.

A Breakthrough in the Era of Calcium Silicate-Based Cements: A Critical Review

Calcium silicate-based cements (CSCs) or mineral trioxide aggregate (MTA) lookalike materials are blocks of cement or root canal sealers produced from calcium (Ca) and silicate. They have superior sealing ability, bioactivity, and marginal adaptability, making them appropriate for various dental treatment applications. Mineral trioxide aggregate is widely used in numerous endodontic repair techniques. The capacity of this cement to promote tissue regeneration and stimulate mineralization accounts for its widespread usage in pulp capping, apexification, apical surgeries, and revascularization. Several studies have been conducted to investigate changes in the components of MTA-based types of cement directed to improve their presentation clinically. To improve flowability, new Ca silicate-based formulations have been introduced commercially. In these new formulations, essential features such as adequate radiopacity and setting time, color stability, alkaline pH, and calcium ion release and biocompatibility must be considered. Owing to an increased range of indications of CSCs, including some for restorative dentistry, and with the emergence of novel silicate calcium-based materials with considerable changes in their compositions, it is necessary to examine the available scientific literature that evaluates their usage in these applications. Therefore, this review paper aims to assess the existing knowledge of CSCs, emphasizing their potential uses in restorative and endodontic dentistry. This report strives to update doctors' understanding of CSCs, allowing for a better therapeutic approach.

Cytotoxicity and bioactive potential of new root repair materials for use with BMP-2 transfected human osteoblast cells

Modified formulations of calcium silicate repair materials with additives have been developed to enhance handling, consistency, biocompatibility and bioactivity. Considering the relevance of osteoblastic cell response to mineralized tissue repair, human osteoblastic cells (Saos-2 cells overexpressing BMP-2) were exposed to mineral trioxide aggregate (MTA) (with calcium tungstate - CaWO4), MTA HP Repair, Bio-C Repair and Bio-C Pulpo. Cell viability was assessed by 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) and neutral red (NR), and cell death, by flow cytometry. Gene expression of bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (RUNX-2), and alkaline phosphatase (ALP) osteogenic markers were evaluated by real-time polymerase chain reaction (RT-qPCR). ALP activity and alizarin red staining (ARS) were used to detect mineralization nodule deposition. Bioactive cements presented no cytotoxic effect, and did not induce apoptosis at the higher dilution (1:12). MTA, Bio-C Repair and Bio-C Pulpo exhibited higher ALP activity than the control group (P < 0.05) after 7 days. MTA, MTA HP and Bio-C Pulpo affected the formation of mineralized nodules (p < 0.05). Exposure to all cement extracts for 1 day increased BMP-2 gene expression. RUNX-2 mRNA was greater in MTA, MTA HP and Bio-C Repair. MTA, MTA HP and Bio-C Pulpo increased the ALP mRNA expression, compared with BMP-2 unexposed cells (P < 0.05). Calcium silicate cements showed osteogenic potential and biocompatibility in Saos-2 cells transfected BMP-2, and increased the mRNA expression of BMP-2, RUNX-2, and ALP osteogenic markers in the BMP-2 transfected system, thereby promoting a cellular response to undertake the mineralized tissue repair.

Present status and future directions: Hydraulic materials for endodontic use

BACKGROUND

Hydraulic materials are used in Endodontics due to their hydration characteristics namely the formation of calcium hydroxide when mixing with water and also because of their hydraulic properties. These materials are presented in various consistencies and delivery methods. They are composed primarily of tricalcium and dicalcium silicate, and also include a radiopacifier, additives and an aqueous or a non-aqueous vehicle. Only materials whose primary reaction is with water can be classified as hydraulic.

OBJECTIVES

Review of the classification of hydraulic materials by Camilleri and the literature pertaining to specific uses of hydraulic cements in endodontics namely intra-coronal, intra-radicular and extra-radicular. Review of the literature on the material properties linked to specific uses providing the current status of these materials after which future trends and gaps in knowledge could be identified.

METHODS

The literature was reviewed using PUBMED, and for each clinical use, the in vitro properties such as physical, chemical, biological and antimicrobial characteristics and clinical data were extracted and evaluated.

RESULTS

A large number of publications were retrieved for each clinical use and these were grouped depending on the property type being investigated.

CONCLUSIONS

The hydraulic cements have made a difference in clinical outcomes. The main shortcoming is the poor testing methodologies employed which provide very limited information and also inhibits adequate clinical translation. Furthermore, the clinical protocols need to be updated to enable the materials to be employed effectively.

Nano-hydroxyapatite-incorporated polycaprolactone nanofibrous scaffold as a dentin tissue engineering-based strategy for vital pulp therapy

OBJECTIVES

Targeting a tissue engineering-based vital pulp therapy (VPT), this study investigated the incorporation of nano-hydroxyapatite (nHA) into polycaprolactone (PCL) nanofibers, and the metabolism of human dental pulp cells (HDPCs) seeded on the scaffolds.

METHODS

PCL-based solutions (10% w/v) containing nHA (0 - control; 0.5; 1.0; or 2.0% w/v) were electrospun into nanofibrous scaffolds. The scaffolds were characterized for morphology and composition (MEV/EDS), solubility, the release of calcium/phosphate (C/P), and modulation of medium pH. Then, HDPCs were seeded on the scaffolds and evaluated for cell viability (alamarBlue and live/dead), adhesion and spreading (F-actin), total protein (TP; Lowry), alkaline phosphatase activity (ALP; thymolphthalein assay), expression of odontogenic genes (RT-qPCR), and formation of a mineralized matrix (Alizarin Red). Data were analyzed with ANOVA and post-hocs (α = 5%).

RESULTS

Higher nHA concentrations roughened fiber surfaces, whereas PCL+ 2%nHA increased the interfibrillar spaces. PCL+ 1%nHA or PCL+ 2%nHA significantly released more C/P but the medium pH was maintained below 8.0. HDPCs viability was not affected by nHA, while cell adhesion/spreading was favored, especially for PCL+ 2%nHA. Higher protein content and ALP activity were seen for scaffolds incorporated with nHA, after 21 days. PCL+ 1%nHA and PCL+ 2%nHA upregulated the expression of DSPP and DMP1 in 14 days, and COL1A1, ALPL, and DMP1 in 21 days. The formation of a mineralized matrix was nHA concentration-dependent, and it was about 9 × higher for PCL+ 2%nHA.

SIGNIFICANCE

nHA-incorporated PCL nanofibrous scaffolds are cytocompatible and can stimulate the adhesion and odontogenic potential of HDPCs. PCL+ 2%nHA formulation is a bioactive tissue engineering-based cell-homing strategy for VPT.

The Effects of 3-Dimensional Bioprinting Calcium Silicate Cement/Methacrylated Gelatin Scaffold on the Proliferation and Differentiation of Human Dental Pulp Stem Cells

A calcium silicate cement/methacrylated gelatin (GelMa) scaffold has been applied in tissue engineering; however, the research on its applications in dental tissue regeneration remains lacking. We investigate the effect of this scaffold on human dental pulp stem cells (hDPSCs). hDPSCs were cultured in 3D-printed GelMa and MTA-GelMa scaffolds. Cell adhesion was evaluated using scanning electron microscopy images. Cells were cultured in an osteogenic differentiation medium, which contained a complete medium or α-MEM containing aqueous extracts of the 3D-printd GelMa or MTA-GelMa scaffold with 2% FBS, 10 mM β-glycerophosphate, 50 μg/mL ascorbic acid, and 10 nM dexamethasone; cell viability and differentiation were shown by WST-1 assay, Alizarin Red S staining, and alkaline phosphatase staining. Quantitative real-time PCR was used to measure the mRNA expression of DSPP and DMP-1. One-way analysis of variance followed by Tukey’s post hoc test was used to determine statistically significant differences, identified at p < 0.05. hDPSCs adhered to both the 3D-printed GelMa and MTA-GelMa scaffolds. There was no statistically significant difference between the GelMa and MTA-GelMa groups and the control group in the cell viability test. Compared with the control group, the 3D-printed MTA-GelMa scaffold promoted the odontogenic differentiation of hDPSCs. The 3D-printed MTA-GelMa scaffold is suitable for the growth of hDPSCs, and the scaffold extracts can better promote odontoblastic differentiation.

Hydroxamate-Based Histone Deacetylase Inhibitors as Potential Mediators to Induce Dentine Regeneration by Human Dental Pulp Cell

Human dental pulp cells (hDPCs) have shown their plasticity when treated with the hydroxamate-based histone deacetylase (HDAC) inhibitor members, Trichostatin A (TSA), and suberoylanilide hydroxamic acid (SAHA). However, a comparison of their potency to stimulate odontoblast-like differentiation and mineralization has not been reported. The aim of our study was to confirm and compare these TSA and SAHA effects. Primary hDPCs cultured with/without various TSA or SAHA concentrations were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), ALP activity, alizarin red staining, and scratch wound healing assays. The inhibitory effect of TSA and SAHA on inhibiting the activity of HDAC was evaluated by HDAC activity assay. Odontoblast-related gene expression was determined using RT-qPCR. The MTT assay indicated that TSA or SAHA did not affect hDPC viability. TSA or SAHA treatment-induced odontoblast-like differentiation as evidenced by a significant increase in alkaline phosphatase activity and mineral deposition after 400 nM TSA or 1 μM SAHA treatment. A significant increase in nuclear factor I C, kruppel like factor 4, dentin matrix acidic phosphoprotein 1, dentin sialophosphoprotein, collagen type I alpha 1 chain, alkaline phosphatase (ALPL), integrin-binding sialoprotein, bone gamma-carboxyglutamate protein, vascular endothelial growth factor A, and cyclin-dependent kinase inhibitor 1A gene expression analyzed by RT-qPCR, at 24, 72 h, 7, and 10 days of treatment. The activity of HDAC in hDPCs culture was significantly inhibited after 72 h TSA and SAHA treatment. The scratch wound healing assay displayed enhanced cell migration at 72 h after TSA or SAHA treatment. Our findings demonstrated that TSA and SAHA have similar stimulatory effects in inducing HDPC odontogenic differentiation and mineralization and propose another potential use of TSA and SAHA to promote dentin regeneration.

Concentrated MTA Repair HP reduced biofilm and can cause reparative action at a distance

AIM

To evaluate in vitro whether MTA Repair HP can induce repair processes at a distance, including its effects on biofilm, cell viability, migration, production of TGF-β, phosphate and ALP, evaluated through MTA diluted extracts.

METHODOLOGY

Initially, antibacterial tests were performed with the bacterium Streptococcus mutans (ATCC 25175) in the presence of MTA extracts (dilutions of 1:1, 1:2 and 1:4). Growth inhibition assay by microdilution in broth, antibiofilm plate assay of young biofilm and antibiofilm assay in confocal microscopy of mature biofilm were carried out. Then, pulp cells were stimulated in the presence of several MTA dilutions, and cell viability (MTT assay), proliferation and migration capacity (scratch assay) were evaluated. To evaluate the capacity of 1:1, 1:2 and 1:4 dilutions of MTA Repair HP to promote the production of important agents of odontogenic differentiation and mineralization, ALP activity, TGF-β secretion and phosphate quantification were measured. Statistical differences were verified using one-way and two-way anova and Tukey's post-tests.

RESULTS

The test dilutions of MTA Repair HP did not inhibit planktonic S. mutans growth but were able to reduce young and mature S. mutans biofilm (p < 0.001). In addition, none of the MTA Repair HP dilutions was cytotoxic for pulp cells. The 1:2 and 1:4 dilutions of MTA Repair HP induced migration and proliferation of pulp cells (p < 0.05). ALP activity and TGF-β secretion were independent of the tested dilution (p < 0.001). Diluted 1:4 MTA Repair HP produced less phosphate than the more concentrated 1:1 and 1:2 MTA dilutions (p < 0.001).

CONCLUSIONS

Undiluted MTA Repair HP reduced S. mutans biofilm, when compared to 1:2 and 1:4 MTA dilutions. Furthermore, none of the tested dilutions was cytotoxic to pulp cells. MTA Repair HP promoted cell migration and proliferation at a distance, assessed through the dilution of the MTA. Even from a distance, MTA Repair HP has the ability to participate in some events related to repair, such as migration, proliferation and TGF production.

Human three-dimensional dental pulp organoid model for toxicity screening of dental materials on dental pulp cells and tissue

AIM

To establish a 3D model for screening the biocompatibility of dental materials/drugs on dental pulp cells and tissue.

METHODOLOGY

Human dental pulp cells (hDPC) and endothelial cells (EC) were mixed with or without human dental pulp derived extracellular matrix (hDP-ECM) according to several protocols and cultured in 3D plates to fabricate 3D organoids. Cell viability and proliferation in organoids were evaluated using Live/Dead cell viability assay and ATPase assay. Organoids were fixed, cut and stained with a H&E staining kit. The expressions of DSPP, DMP-1, CD31, vWF and COL1A in 3D organoids were evaluated using immunofluorescence. To assess the feasibility of 3D organoids on drug/material toxicity screening, the organoids were treated with lipopolysaccharides (LPS) or iRoot BP. Then, cell viability and apoptosis were assessed. The expressions of IL-6, TNF-α, and IL-1β were compared in LPS-treated and non-treated organoids. Alizarin Red S staining was used to evaluate calcium deposit formation in organoids. Data were analysed using one-way anova followed by Tukey's post hoc comparison.

RESULTS

The 3D spheres/organoids were formed at day 1 or day 2. Cells in 3D organoids maintained a high viability rate and low proliferation activity. The level of CD31 increased significantly (p < .05) when EC were added to coculture with hDPC. The expressions of odontogenesis-associated proteins (DSPP, COL1A) upregulated (p < .05) with the addition of hDP-ECM. Level of IL-6 expression and rates of dead and apoptotic cells in 3D organoids were increased significantly (p < .05) in response to LPS. Calcium deposit formation was observed in iRoot BP-treated organoids.

CONCLUSIONS

Coculture of hDPC and EC in the presence of hDP-ECM formed functional dental pulp organoids. The experimental model provides an alternative tool for toxicity screening of dental pulp capping agents and dental pulp regeneration research.

The molecular functions of Biodentine and mineral trioxide aggregate in lipopolysaccharide-induced inflamed dental pulp cells

AIM

To explore the proliferation, adhesion and differentiation response and the underlying mechanisms that occur in lipopolysaccharide (LPS)-induced inflamed dental pulp cells (DPCs) in contact with Biodentine and mineral trioxide aggregate (MTA).

METHODOLOGY

The DPCs were isolated from three healthy donors and named DPC-H1 to DPC-H3. The DPCs were pre-cultured with 2 or 5 μg mL^-1 LPS for 24 h to induce inflammation. The expression of inflammation marker miR-146a was detected by q-PCR. The normal and LPS-induced DPCs were further treated with 0.14 mg mL^-1 Biodentine or 0.13 mg mL^-1 MTA for 24 h. MTT assay and adhesion assay were used to analyse the changes of cell phenotypes. DSPP, AKT and ERK expressions were detected by Western blotting. The data were analysed by Mann-Whitney test or two-way anova. Differences were considered statistically significant when P < 0.05.

RESULTS

In LPS-induced DPCs, Biodentine and MTA treatment neither induced nor aggravated LPS-induced inflammation, but their presence did increase the expression of the odontogenic differentiation marker DSPP. Under 2 or 5 μg mL^-1 LPS-induced inflammation, Biodentine and MTA promoted the proliferation of DPC cells, and significantly in DPC-H2 (P < 0.0001 for both reagents). With the treatment of 2 μg mL^-1 LPS, the cell adhesion of DPCs on the fibronectin-coated culture plates was increased significantly by Biodentine (P = 0.0413) and MTA (P < 0.0001). Biodentine and MTA regulated cell adhesion on the fibronectin-coated culture plates (P < 0.0001 for both reagents) and proliferation (P < 0.0001 for both reagents) via the AKT pathway. However, the AKT pathway was not involved in the expression of DSPP induced by Biodentine and MTA.

CONCLUSION

Biodentine and MTA enhanced the proliferation, adhesion and differentiation of LPS-induced DPCs. The proliferation and adhesion process induced by Biodentine and MTA was via the AKT pathway. However, the cellular differentiation process might not use the same pathway, and this needs to be explored in future studies.

Cytocompatibility and bioactive properties of the new dual-curing resin-modified calcium silicate-based material for vital pulp therapy

OBJECTIVE

The aim of the present study was to evaluate the in vitro biocompatibility of Theracal PT, Theracal LC, and MTA Angelus, considered as bioactive materials used for vital pulp treatment, on human dental pulp stem cells (hDPSCs).

MATERIALS AND METHODS

Human dental pulp stem cells (hDPSCs) were isolated from third molars, and material eluates were prepared (undiluted, 1:2, and 1:4 ratios). The hDPSC cytotoxicity, adhesion, morphology, viability, and cell migration were assessed. The mineralization nodule formation was determined by Alizarin red S staining (ARS). The odonto/osteogenic differentiation potential was assessed by osteo/odontogenic marker expression real-time qPCR. The chemical composition and ion release of the vital pulp materials were determined by energy dispersive X-ray (EDX) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. Statistical differences were assessed by ANOVA and Tukey's test (p < 0.05).

RESULTS

The three vital pulp materials showed variable levels of calcium, tungsten, silicon, and zirconium release and in their chemical composition. Cytocompatibility assays revealed higher hDPSC viability and migration rates when treated with Theracal PT than with Theracal LC. The lowest cell adhesion and spreading were observed in all Theracal LC-treated groups, whereas the highest were observed when treated with MTA. Theracal PT and MTA promoted the upregulation of DSPP and RUNX2 gene expression (p < 0.05). After 21 days, both MTA Angelus and Theracal PT-treated cells exhibited a significantly higher mineralized nodule formation than the negative control (p < 0.05).

CONCLUSIONS

This study demonstrates the favorable in vitro cytocompatibility and bioactive properties of the recently introduced Theracal PT and the well-established MTA Angelus on hDPSCs, as opposed to Theracal LC. More studies, including in vivo animal testing are suggested before these new formulations might be used in the clinical setting.

CLINICAL RELEVANCE

Theracal PT is a new material that could be clinically suitable for vital pulp therapy. Further studies considering its biocompatibility and bioactivity are necessary.

Cytocompatibility and Bioactive Properties of Hydraulic Calcium Silicate-Based Cements (HCSCs) on Stem Cells from Human Exfoliated Deciduous Teeth (SHEDs): A Systematic Review of In Vitro Studies

The implementation of hydraulic calcium silicate-based endodontic cements (HCSCs) in biologically based endodontic procedures for the primary dentition has been recently investigated, focusing on the biological response of stem cells from human exfoliated deciduous teeth (SHEDs) towards them. The present systematic review aimed to present a qualitative synthesis of the available literature consisting of in vitro assays, which assessed the cytocompatibility and bioactive properties of HCSCs in direct contact with SHEDs. Following the PRISMA statement, an electronic database search was carried out in Medline, Scopus, Embase, Web of Science, and SciELO on March 31st and updated on November 16th, 2020. In vitro studies evaluating the biological response of SHEDs to the treatment with HCSCs were eligible. Within the term biological response, assays assessing the cytocompatibility (i.e., cell viability, migration, proliferation), cell plasticity or differentiation (i.e., osteo/odontogenic marker expression), and bioactivity or biomineralization (i.e., mineralized nodule formation) were included. A total of seven studies were included after the selection process. The study sample comprised an extensive range of cell viability, migration, proliferation, adhesion, and bioactivity assays regarding the biological response of SHEDs towards five different commercially available HCSCs (MTA, ProRoot MTA, Biodentine, iRoot BP Plus, and Theracal LC). Biodentine, MTA, and iRoot BP Plus showed significant positive results in cytocompatibility and bioactivity assays when cultured with SHEDs. The results from in vitro assays assessing the cytocompatibility and bioactivity of the HCSCs MTA, Biodentine, and iRoot BP Plus towards SHEDs support their use in vital pulp treatment for the primary dentition.

Cytotoxicity of NeoMTA Plus, ProRoot MTA and Biodentine on human dental pulp stem cells

Background/purpose

Dental pulp stem cells (DPSCs) play a crucial role in the tissue healing process through odontoblast like cell differentiation. The aim of this study was to evaluate the biocompatibility and compare the potential invitro cytotoxic effects of NeoMTA Plus, ProRootMTA and Biodentine on human dental pulp stem cells (hDPSCs).

Materials and methods

To assess the effects of NeoMTA Plus, ProRoot MTA and Biodentine extracts at 1st, 3rd and 7th d on hDPCs, cell populations was determined by flow cytometry using an Annexin V detection kit. The data were analyzed statistically using the Kruskal–Wallis test. A p < 0.05 was considered as statistically significant.

Results

All groups showed cell viability similar to that of the control group on 1st, 3rd and 7th d. Although Biodentine exhibited higher cell viability rates than the other material groups, no statistically significant differences were noted between the sampled days (p > 0.05).

Conclusion

All materials extracts are not cytotoxic and do not induce apoptosis in the hDPSCs. These results suggest that all the tested materials can lead to positive outcomes when used as reparative biomaterials.

Characterization of Living Dental Pulp Cells in Direct Contact with Mineral Trioxide Aggregate

Mineral trioxide aggregate (MTA) was introduced as a material for dental endodontic regenerative therapy. Here, we show the dynamics of living dental pulp cells in direct contact with an MTA disk. A red fluorescence protein (DsRed) was introduced into immortalized porcine dental pulp cells (PPU7) and cloned. DsRed-PPU7 cells were cultured on the MTA disk and cell proliferation, chemotaxis, the effects of growth factors and the gene expression of cells were investigated at the biological, histomorphological and genetic cell levels. Mineralized precipitates formed in the DsRed-PPU7 cells were characterized with crystal structural analysis. DsRed-PPU7 cells proliferated in the central part of the MTA disk until Day 6 and displayed a tendency to move to the outer circumference. Both transforming growth factor beta and bone morphogenetic protein promoted the proliferation and movement of DsRed-PPU7 cells and also enhanced the expression levels of odontoblastic gene differentiation markers. Mineralized precipitates formed in DsRed-PPU7 were composed of calcium and phosphate but its crystals were different in each position. Our investigation showed that DsRed-PPU7 cells in direct contact with the MTA disk could differentiate into odontoblasts by controlling cell–cell and cell–substrate interactions depending on cell adhesion and the surrounding environment of the MTA.

Influence of resveratrol application with pulp-capping materials on the genetic expression levels of stem cells

AIM

To evaluate in a laboratory setting the response of human mesenchymal stem cells (MSCs) to pulp-capping materials with and without resveratrol (RSV).

METHODOLOGY

Five materials, Calcimol LC, Life, TheraCal LC, ProRoot MTA and Biodentine, were prepared according to the manufacturers' instructions. Human MSCs were then exposed to these materials, with and without RSV, for 24 h (n = 8). Cell viability was evaluated using the MTT assay, and total cell death was quantified by annexin V-FITC staining with flow cytometry. The expression levels of the IL-8, IL-10, HBD-2 and BCL-2 genes were investigated using real-time polymerase chain reaction (RT-PCR). Data obtained from MTT test were analysed using one-way anova, and Tukey's multiple-comparison test. The paired Student t test was employed to compare the effects of materials on gene expression (significance level of 5%).

RESULTS

The group cell viabilities were Calcimol LC 53%, Life 43%, TheraCal LC 78%, ProRoot MTA 75% and Biodentine 78%. Calcimol LC and Life exhibited significant differences compared with the control groups (P < 0.05). The percentages of necrotic/late apoptotic cells associated with Calcimol LC and TheraCal LC were greater than in the other materials. However, when RSV was added to wells containing materials, cell viability increased to Calcimol LC 63%, Life 52%, TheraCal LC 82%, ProRoot MTA 91% and Biodentine 96%, and the percentages of early apoptotic and late apoptotic/necrotic cells decreased. Calcimol LC + RSV and Life + RSV differed significantly from the control group (P < 0.05). The expression of IL-8 gene was high for all materials, ProRoot MTA caused significant overexpression, and the addition of RSV reduced the expression of IL-8 in the Calcimol LC, TheraCal LC and ProRoot MTA groups and led to increased expression of IL-10 in the Calcimol LC, Life and Biodentine groups. HBD-2 and BCL-2 exhibited increased expression in ProRoot MTA with RSV (P < 0.05).

CONCLUSIONS

The addition of RSV exerted a protective effect on MSCs and regulated the inflammatory process by altering the expression levels of pro- and anti-inflammatory genes.

Cytotoxicity and Bioactivity of Dental Pulp-Capping Agents towards Human Tooth-Pulp Cells: A Systematic Review of In-Vitro Studies and Meta-Analysis of Randomized and Controlled Clinical Trials

Background. In the era of biology-driven endodontics, vital pulp therapies are regaining popularity as a valid clinical option to postpone root-canal treatment. In this sense, many different materials are available in the market for pulp-capping purposes. Objectives. The main aim of this systematic review and meta-analysis was to examine literature regarding cytotoxicity and bioactivity of pulp-capping agents by exposure of human dental pulp cells of primary origin to these materials. A secondary objective was to evaluate the inflammatory reaction and reparative dentin-bridge formation induced by the different pulp-capping agents on human pulp tissue. Data sources. A literature search strategy was carried out on PubMed, EMBASE and the Web of Science databases. The last search was done on 1 May 2020. No filters or language restrictions were initially applied. Two researchers independently selected the studies and extracted the data. Study selection included eligibility criteria, participants and interventions, study appraisal and synthesis methods. In vitro studies were included when human dental pulp cells of primary origin were (in) directly exposed to pulp-capping agents. Parallel or split-mouth randomized or controlled clinical trials (RCT or CCT) were selected to investigate the effects of different pulp-capping agents on the inflammation and reparative bridge-formation capacity of human pulp tissue. Data were synthesized via odds ratios (95% confidence interval) with fixed or random effects models, depending on the homogeneity of the studies. The relative risks (95% confidence interval) were presented for the sake of interpretation. Results. In total, 26 in vitro and 30 in vivo studies were included in the systematic review and meta-analysis, respectively. The qualitative analysis of in vitro data suggested that resin-free hydraulic calcium-silicate cements promote cell viability and bioactivity towards human dental pulp cells better than resin-based calcium-silicate cements, glass ionomers and calcium-hydroxide cements. The meta-analysis of the in vivo studies indicated that calcium-hydroxide powder/saline promotes reparative bridge formation better than the popular commercial resin-free calcium-silicate cement Pro-Root MTA (Dentsply-Sirona), although the difference was borderline non-significant (p = 0.06), and better than calcium-hydroxide cements (p < 0.0001). Moreover, resin-free pulp-capping agents fostered the formation of a complete reparative bridge better than resin-based materials (p < 0.001). On the other hand, no difference was found among the different materials tested regarding the inflammatory effect provoked at human pulp tissue. Conclusions. Calcium-hydroxide (CH) powder and Pro-Root MTA (Dentsply-Sirona) have shown excellent biocompatibility in vitro and in vivo when tested on human cells and teeth. Their use after many years of research and clinical experience seems safe and proven for vital pulp therapy in healthy individuals, given that an aseptic environment (rubber dam isolation) is provided. Although in vitro evidence suggests that most modern hydraulic calcium-silicate cements promote bioactivity when exposed to human dental pulp cells, care should be taken when these new materials are clinically applied in patients, as small changes in their composition might have big consequences on their clinical efficacy. Key findings (clinical significance). Pure calcium-hydroxide powder/saline and the commercial resin-free hydraulic calcium-silicate cement Pro-Root MTA (Dentsply-Sirona) are the best options to provide a complete reparative bridge upon vital pulp therapy. Systematic review registration number. PROSPERO registration number: CRD42020164374.

The effect of four materials on direct pulp capping: An animal study

The aim of this study was to investigate the outcomes of direct pulp capping performed with two types of tricalcium silicate-based materials (mineral trioxide aggregate/MTA and Biodentine/BD); nano-hydroxyapatite (nHAP) crystals or calcium hydroxide (CH) in dogs. Following mechanical exposure, the pulps were randomly capped with one of the four materials. Histological analyses were performed to examine the outcomes after 7 days or 3 months. At 7 days, BD and nHAP showed significantly less inflammatory cell response than MTA and CH. At 3 months, the inflammatory cell response and tissue necrosis were significantly higher in the CH group. There was no significant difference between the tested materials in the calcific bridge formation after 7 days; however, a significant difference was noticed at the 3-month period. Tricalcium silicate-based cements and nHAP are potential alternatives to CH in vital pulp therapy following accidental pulp exposure.

Histopathological, histoenzymological, immunohistochemical and immunofluorescence analysis of tissue response to sealing materials after furcation perforation

AIM

To evaluate in vivo tissue responses after sealing furcation perforations in dog's teeth with either Biodentine™, mineral trioxide aggregate (MTA) or gutta-percha, by means of histopathological, histoenzymological, immunohistochemical and immunofluorescence analysis.

METHODOLOGY

After root canal treatment, perforations were created in the central region of the pulp chamber floor using a round diamond bur and filled with one or other of the materials. The animals were euthanized after 120 days, and the teeth (n = 30) were processed for histopathological analysis of new mineralized tissue formation and collagen fibre reinsertion, immunohistochemical analysis of osteopontin (OPN) and alkaline phosphatase (ALP) and immunofluorescence analysis for bone morphogenetic protein (BMP-2), cementum attachment protein (CAP), bone sialoprotein (BSP), osteocalcin (OCN) and cementum protein1 (CEMP1). Histoenzymology was performed for TRAP activity and osteoclast count. Data were analysed statistically (α = 0.05) using chi-square and Kruskal-Wallis tests.

RESULTS

Gutta-percha did not induce mineralized tissue formation. MTA and Biodentine^TM formed mineralized tissue in 88% and 92% of specimens, respectively, with no significant difference (P > 0.05). Gutta-percha was associated with scattered collagen fibres parallel to the perforations. Groups treated with MTA or Biodentine^TM had partial fibre reinsertion perpendicular to the newly formed mineralized tissue. All materials induced OPN and ALP expression, weakest for gutta-percha and strongest for MTA (P < 0.05). Only MTA induced BMP-2, BSP, OCN, CAP and CEMP1 expression. Osteoclast counts were similar in all groups (P = 0.97).

CONCLUSIONS

Mineral trioxide aggregate and Biodentine^TM were biocompatible, with formation of mineralized tissue and partial reinsertion of collagen fibres. In addition, the participation of several molecules by which calcium silicate-based materials induce the formation of mineralized tissue were noted, with expression of ALP and OPN mineralization markers, without interference in the number of osteoclasts. Only MTA stimulated the expression of proteins associated with the formation of a cementum-like mineralized tissue.

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.

Addition of zirconium oxide to Biodentine increases radiopacity and does not alter its physicochemical and biological properties

Objectives:

To evaluate the radiopacity of Biodentine (BD) and BD associated with 15% calcium tungstate (BDCaWO₄) or zirconium oxide (BDZrO₂), by using conventional and digital radiography systems, and their physicochemical and biological properties.

Materials and Methods:

Radiopacity was evaluated by taking radiographs of cement specimens (n=8) using occlusal film, photostimulable phosphor plates or digital sensors. Solubility, setting time, pH, cytocompatibility and osteogenic potential were also evaluated. Data were analyzed using one-way ANOVA and Tukey post-test or two-way ANOVA and Bonferroni post-test (α=0.05).

Results:

BD radiopacity was lower than 3 mm Al, while BD ZrO₂ and BD CaWO₄ radiopacity was higher than 3 mm Al in all radiography systems. The cements showed low solubility, except for BDCaWO₄. All cements showed alkaline pH and setting time lower than 34 minutes. MTT and NR assays revealed that cements had greater or similar cytocompatibility in comparison with control. The ALP activity in all groups was similar or greater than the control. All cements induced greater production of mineralized nodules than control.

Conclusions:

Addition of 15% ZrO₂ or CaWO₄ was sufficient to increase the radiopacity of BD to values higher than 3 mm Al. BD associated with radiopacifiers showed suitable properties of setting time, pH and solubility, except for BDCaWO₄, which showed the highest solubility. All cements had cytocompatibility and potential to induce mineralization in Saos-2 cells. The results showed that adding 15% ZrO₂ increases the radiopacity of BD, allowing its radiography detection without altering its physicochemical and biological properties.

Bioactivity of Bioceramic Materials Used in the Dentin-Pulp Complex Therapy: A Systematic Review

Dentistry-applied bioceramic materials are ceramic materials that are categorized as bioinert, bioactive and biodegradable. They share a common characteristic of being specifically designed to fulfil their function; they are able to act as root canal sealers, cements, root repair or filling materials. Bioactivity is only attributed to those materials which are capable of inducing a desired tissue response from the host. The aim of this study is to present a systematic review of available literature investigating bioactivity of dentistry-applied bioceramic materials towards dental pulp stem cells, including a bibliometric analysis of such a group of studies and a presentation of the parameters used to assess bioactivity, materials studied and a summary of results. The research question, based on the PICO model, aimed to assess the current knowledge on dentistry-based bioceramic materials by exploring to what extent they express bioactive properties in in vitro assays and animal studies when exposed to dental pulp stem cells, as opposed to a control or compared to different bioceramic material compositions, for their use in the dentin-pulp complex therapy. A systematic search of the literature was performed in six databases, followed by article selection, data extraction, and quality assessment. Studies assessing bioactivity of one or more bioceramic materials (both commercially available or novel/experimental) towards dental pulp stem cells (DPSCs) were included in our review. A total of 37 articles were included in our qualitative review. Quantification of osteogenic, odontogenic and angiogenic markers using reverse transcriptase polymerase chain reaction (RT-PCR) is the prevailing method used to evaluate bioceramic material bioactivity towards DPSCs in the current investigative state, followed by alkaline phosphatase (ALP) enzyme activity assays and Alizarin Red Staining (ARS) to assess mineralization potential. Mineral trioxide aggregate and Biodentine are the prevalent reference materials used to compare with newly introduced bioceramic materials. Available literature compares a wide range of bioceramic materials for bioactivity, consisting mostly of in vitro assays. The desirability of this property added to the rapid introduction of new material compositions makes this subject a clear candidate for future research.

Tricalcium silicate-based cements: properties and modifications

Mineral trioxide aggregate (MTA) has been widely used for different reparative procedures in endodontics. The extensive use of this cement for pulp capping, apexifications, apical surgeries, and revascularization is related to its ability to induce tissue repair and to stimulate mineralization. Several research studies have tested modifications in the composition of MTA-based cements in order to enhance their clinical performance. Novel formulations have been introduced in the market with the aim of increasing flowability. Important properties such as appropriate radiopacity and setting time, color stability, alkaline pH, release of calcium ions, and biocompatibility have to be considered in these new formulations. The latest research studies on the physical, chemical, and biological properties of tricalcium silicate-based cements are discussed in this critical review.

Bone tissue reaction, setting time, solubility, and pH of root repair materials

OBJECTIVES

This study aims to compare the bone tissue reaction, setting time, solubility, and pH of NeoMTA Plus, Biodentine (BD), and MTA Angelus (MTA-A).

MATERIALS AND METHODS

Initial and final setting times (n = 7) and solubility up to 7 days (n = 11) were evaluated in accordance with ASTM C266-15 and ANSI/ADA Specification No. 57, respectively. pH (n = 10) was measured up to 28 days. Bone tissue reactions in 48 rats' femur were histologically analyzed after 7, 30, and 90 days. ANOVA and Tukey's tests compared setting time, solubility, and pH data; bone reactions data were compared by Kruskal-Wallis and Dunn's tests.

RESULTS

NeoMTA Plus had longer initial and final setting times than MTA-A and BD (P < 0.05). At 7 days, BD showed the highest solubility, similar to NeoMTA Plus (P > 0.05) and different from MTA-A (P < 0.05). NeoMTA Plus had a progressive mass loss over time; at 7 days, it was significantly different from the initial mass (P < 0.05). BD showed higher pH in the periods assessed when compared to the other materials (P < 0.05). Bone tissue repair had no differences between groups in each experimental period (P > 0.05). All groups presented no difference from 30 to 90 days (P > 0.05) and had better bone repair at 90 days than at 7 days (P < 0.05).

CONCLUSIONS

NeoMTA Plus, BD, and MTA-A showed satisfactory setting time, high mass loss, alkaline pH, and allowed bone repair.

CLINICAL RELEVANCE

Calcium silicate-based cements are indicated for multiple clinical situations. NeoMTA Plus and BD showed satisfactory physical-chemical and biological properties, being considered as alternatives to MTA-A, as root repair materials for clinical use.

Physico-chemical and Biological Properties of a New Portland Cement-based Root Repair Material

Could conventional endodontic treatment have an impact on oral health-related quality of life? There are still unresolved questions regarding this theme. In order to answer them, a systematic review on the available literature was undertaken to identify the methodological quality of and the risk of bias in all relevant studies. A broad search for articles was conducted, and only articles published before May 2016 were considered for review. The following portals were used: Pubmed, VHL (Medline, SciELO, Lilacs and BBO), Cochrane Library, and Web of Science. The keywords used for the search were ‘quality of life’ and ‘root canal treatment.’ Furthermore, we included MeSH synonyms, related terms and free terms. Articles written in any language were included according to the PICOS approach (population, intervention, comparison, outcome and study design). After application of these eligibility criteria, selected articles were qualified by assessing their methodological quality and potential risk of bias. The initial search identified 302 references. After excluding duplicated abstracts and analysing the titles and abstracts, 6 were selected. One study was added via manual search of the reference lists. From these, 2 were eligible for quality assessment and were classified as being of high methodological quality and as having low risk of bias. Based on these studies, it can be concluded that conventional endodontic treatment improves oral health-related quality of life. However, these results should be interpreted with caution, due to the lack of important methodological details in the included studies. Additional investigations are warranted to provide more evidence on this subject.