Human dental pulp cell responses to new calcium silicate-based endodontic materials

Advances and challenges in regenerative dentistry: A systematic review of calcium phosphate and silicate-based materials on human dental pulp stem cells

Conventional dentistry faces limitations in preserving tooth health due to the finite lifespan of restorative materials. Regenerative dentistry, utilizing stem cells and bioactive materials, offers a promising approach for regenerating dental tissues. Human dental pulp stem cells (hDPSCs) and bioactive materials like calcium phosphate (CaP) and silicate-based materials have shown potential for dental tissue regeneration. This systematic review aims to investigate the effects of CaP and silicate-based materials on hDPSCs through in vitro studies published since 2015. Following the PRISMA guidelines, a comprehensive search strategy was implemented in PubMed MedLine, Cochrane, and ScienceDirect databases. Eligibility criteria were established using the PICOS scheme. Data extraction and risk of bias (RoB) assessment were conducted, with the included studies assessed for bias using the Office of Health and Translation (OHAT) RoB tool. The research has been registered at OSF Registries. Ten in vitro studies met the eligibility criteria out of 1088 initial studies. Methodological heterogeneity and the use of self-synthesized biomaterials with limited generalizability were observed in the included study. The findings highlight the positive effect of CaP and silicate-based materials on hDPSCs viability, adhesion, migration, proliferation, and differentiation. While the overall RoB assessment indicated satisfactory credibility of the reviewed studies, the limited number of studies and methodological heterogeneity pose challenges for quantitative research. In conclusion, this systematic review provides valuable insights into the effects of CaP and silicate-based materials on hDPSCs. Further research is awaited to enhance our understanding and optimize regenerative dental treatments using bioactive materials and hDPSCs, which promise to improve patient outcomes.

Investigation of the hydration process and biological activity of a novel nanosilver incorporated dicalcium silicate based retrograde filling material

Background

Although several materials have been used for retrograde filling following apical surgeries, there is no consensus on a single best material. Tricalcium silicate-based types of cement have been developed as root-end filling materials mainly due to tricalcium silicate's hydraulic properties. However, its unfavorable setting characteristics and minimal antimicrobial properties have necessitated the introduction of new additives into the existing commercially available materials. To design an affordable product based on a dicalcium silicate with a shorter set time, minimal cytotoxic complications, and enhanced antibacterial activity, we developed a new endodontic cement from pure raw materials, intending to satisfy the prerequisites of ideal retrograde material.

Methods

The composition of the experimental calcium silicate-based cement included the addition of calcium chloride and silver nanoparticles in varying concentrations. Structural characterization was carried out using energy dispersive analysis by X-rays using scanning electron microscope (EDAX SEM) and hydration characteristics were performed using an X-ray diffractometer (XRD). The experimental material was further evaluated for biocompatibility using MTT ([3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide)assay and antibacterial activity was evaluated using an agar diffusion test against Enterococcus faecalis.

Results

The structural characterization and hydration characteristics revealed that the experimental cement was dicalcium silicate based with favorable biocompatibility and enhanced antibacterial activity. Tricalcium silicate based mineral trioxide aggregate (MTA) also had favourable biocompatibility, however, its antibacterial activity was significantly decreased when compared to the novel cement.

Conclusion

All hydraulic cements that are available in the dental market are predominantly tricalcium silicate-based materials. There has been no evidence in the literature to date wherein it has been explored whether a dicalcium silicate-based hydraulic cement can solely be used in root-end cavities. The findings of the study revealed a dicalcium silicate based retrograde filling material with favourable biocompatibility exhibited immediately as well as in the set samples. Incorporation of silver nanoparticles boosted the antibacterial activity when compared to that of ProRoot MTA. This material could potentially reinstate the usual hype created with tricalcium silicate types of cement since dicalcium silicate cements also exhibit similar properties.

Exposure to lipopolysaccharide and calcium silicate-based materials affects the behavior of dental pulp cells

This study assessed the cell viability, cytokine production, and mineralization potential of human dental pulp cells (hDPCs) after exposure to lipopolysaccharide (LPS) and application of calcium silicate-based materials (CSBM). Characterization of the CSBM was performed by infrared spectroscopy (n = 3). Extracts of Bio-C Repair, Biodentine, Cimmo HD, and MTA Repair HP were prepared and diluted (1:1, 1:4, and 1:16). Culture of hDPCs was established and treated or not with 1 µg/mL of LPS from Escherichia coli for 7 days. MTT assay was used to assess cell viability at 24, 48, and 72 h (n = 6). Alkaline phosphatase (ALP) activity was assayed on day 7 (n = 4). Il-10 and TNF-α were quantified by ELISA at 24 h (n = 6). Data were analyzed by ANOVA and Tukey's test (α = 0.05). Cell viability of LPS-activated hPDCs was higher than untreated control in 48 and 72 h (p < 0.05). Differences between non-treated and LPS-activated hPDCs were observed for Biodentine and Cimmo HP (p < 0.05). The CSBM influenced the cell viability (p < 0.05). ALP activity was higher in LPS-activated hDPCs (p < 0.05). No changes in the concentration of TNF-α were observed between groups (p > 0.05). The CSBM increased the Il-10 production (p < 0.05). LPS-activated hDPCs presented increased cell viability and ALP activity. The CSBM showed mild toxicity and was able to enhance the cell viability and mineralization potential of untreated and LPS-activated hDPCs. The CSBM also induced anti-inflammatory mechanisms without compromising pro-inflammatory ones.

Effect of biodentine coated with emdogain on proliferation and differentiation of human stem cells from the apical papilla

BACKGROUND

This study assessed the effect of Biodentine coated with Emdogain (Biodentine/Emdogain) on proliferation and differentiation of human stem cells from the apical papilla (SCAPs). METHODS AND RESULTS: In this in vitro, experimental study, SCAPs were isolated from two immature impacted third molars and cultured. After ensuring the stemness of the cells by assessing the cell surface markers, they were exposed to Biodentine, Emdogain, and Biodentine/Emdogain for 24 and 72 h. The control cells did not receive any intervention. Cell viability was evaluated by the methyl thiazolyl tetrazolium assay. Expression of odontogenic differentiation genes was analyzed by the quantitative reverse transcription polymerase chain reaction. Alkaline phosphatase (ALP) activity was quantified by the respective kit. Data were analyzed by one-way ANOVA, t-test, and Mann-Whitney test (α = 0.05). Cell viability did not change after 24 h of exposure to biomaterials. At 72 h, the viability of the cells exposed to Biodentine and Biodentine/Emdogain decreased compared with the control group. The expression of dentin sialophosphoprotein, dentin matrix protein 1, and bone sialoprotein genes, and ALP activity significantly increased in all three experimental groups, compared with the control group at both 24 and 72 h; this increase was significantly greater in Biodentine/Emdogain group. The number of mineralized nodules significantly increased in all groups after 72 h with a greater rate in Biodentine/Emdogain group.

CONCLUSIONS

All biomaterials increased the differentiation of SCAPs, expression of odontogenic genes, and ALP activity, but Biodentine/Emdogain was significantly more effective for this purpose.

Histological Evaluation of Periradicular Tissue Inflammatory Reactions and Calcified Tissue Formations After Implantation of Experimental Calcium Silicate and Hydroxyapatite Based Nanostructural Cements Into Root Canals of Rabbits Teeth

The aim of the study was to evaluate inflammatory tissue reactions and the formation of calcified tissue after implantation of experimental nanostructured calcium silicate cement (CS) and hydroxyapatite with calcium silicate cement (HA-CS) into root canals of rabbits’ teeth. The study was conducted on four rabbits of the genus Oryctolagus cuniculus. After instrumentation and irrigation, the root canals of the central incisors were dried and filled with CS, HA-CS and control material (MTA Angelus). The animals were sacrificed after 28 days. After histological preparation and hematoxylin-eosin staining, tissue samples were evaluated for the intensity and extension of inflammatory tissue reaction; continuity, morphology and thickness of the newly formed calcified tissue; and presence of giant cells, materials particles and microorganisms. Kruskal Wallis and Dunn’s post hoc test were used for data analysis (α=0.05). There were no significant differences in the intensity of inflammatory reactions between CS, HA-CS and MTA control. HA-CS showed significantly better results than MTA and CS with respect to continuity of the newly formed calcified tissue (P=0.003 and P=0.010, respectively). Significant differences in thickness of the calcified tissue existed between CS and MTA (P=0.004) and between HA-CS and MTA (P=0.012). Application of CS and HA-CS resulted in minimal inflammatory tissue response, similar to the MTA control. CS and HA-CS were more efficient than MTA in supporting hard tissue formation. The best organized newly formed calcified tissue was seen after HA-CS application.

Odontogenic differentiation of inflamed dental pulp stem cells (IDPSCs) on polycaprolactone (PCL) nanofiber blended with hydroxyapatite

The objective of this study was to develop electrospun polycaprolactone (PCL) membranes blended with hydroxyapatite (HA) and evaluate its potential in differentiating inflamed dental pulp stem/progenitor cells (IDPSCs) into odontoblasts. Electrospun nanofibrous membrane consisting of PCL blended with 10 wt% and 15 wt% of HA were fabricated and the characterization was done by Scanning electron microscopy (SEM), Fourier- transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and contact angle analysis. Cytocompatibility, cell adhesion and odontogenic differentiation ability of the membranes were assessed by MTT, Live/Dead, SEM/DAPI and qPCR studies. The mineral deposition ability of the membranes with IDPSCs was estimated by SEM-EDS. The SEM analysis revealed a nanofibrous texture with an average fiber diameter of 140 nm for PCL, 220 nm for PCL10%HA and 250 nm for PCL15%HA. Among the membranes tested, PCL10%HA favored positive cell attachments, upregulated expression of DSPP and ALP gene and higher Ca/P ratio compared to PCL and PCL15%HA.

Nitric Oxide in Dental Pulp Tissue: From Molecular Understanding to Clinical Application in Regenerative Endodontic Procedures

Nitric oxide (NO), which is synthesized by the enzyme NO synthase (NOS), is a versatile endogenous molecule with multiple biological effects on many tissues and organs. In dental pulp tissue, NO has been found to play multifaceted roles in regulating physiological activities, inflammation processes, and tissue repair events, such as cell proliferation, neuronal degeneration, angiogenesis, and odontoblastic differentiation. However, there is a deficiency of detailed discussion on the NO-mediated interactions between inflammation and reparative/regenerative responses in wounded dental pulp tissue, which is a central determinant of ultimate clinical outcomes. Thus, the purpose of this review is to outline the current molecular understanding on the roles of Janus-faced molecule NO in dental pulp physiology, inflammation, and reparative activities. Based on this knowledge, advanced physicochemical techniques designed to manipulate the therapeutic potential of NOS and NO production in endodontic regeneration procedures are further discussed. Impact statement The interaction between inflammation and reparative/regenerative responses is very important for regenerative endodontic procedures, which are biologically based approaches intended to replace damaged tissues. Inside dental pulp tissue, endogenous nitric oxide (NO) is generated mainly by immunocompetent cells and dental pulp cells and mediates not only inflammatory/immune activities but also signaling cascades that regulate tissue repair and reconstruction, indicating its involvement in both tissue destruction and regeneration. Thus, it is feasible that NO acts as one of the indicators and modulators in dental pulp repair or regeneration under physiological and pathological conditions.

Strontium-Substituted Dicalcium Silicate Bone Cements with Enhanced Osteogenesis Potential for Orthopaedic Applications

Incorporating Sr element in biomaterials for bone implants is an effective way to improve their biological performance, as Sr element has been proved to enhance bone regeneration and depress bone resorption activity. In the present study, we developed a Sr-incorporated dicalcium silicate (C2S) bone cement as a potential candidate for bioactive self-setting bone cement in orthopaedics and stomatology. The Sr-C2S powders containing 0.3–6.8% Sr in molar ratio were prepared by means of chemical co-precipitation, and the results of XRD analysis indicated the incorporation of Sr element into the lattice of C2S. Sr-C2S bone cements, as prepared by mixing the powders with water, have a final setting time of 570 to 594 min, and compressive strength higher than that of C2S bone cement within certain incorporation range. The Sr-C2S bone cements possessed good in vitro bioactivity by inducing apatite formation in simulated body fluid (SBF) within 7 days. Moreover, the proliferation activity of human bone marrow mesenchymal stem cells (hBMSCs) with Sr-C2S bone cements was significantly higher than that with C2S bone cement, and the alkaline phosphatase (ALP) activity of hBMSCs was also enhanced with addition of Sr element in Sr-C2S groups. The Sr-C2S might therefore be a bioactive self-setting material with enhanced biological performance and holds the prospect for application in the bone regeneration area.

Dental pulp stem cells and osteogenesis: an update

Dental pulp stem cells constitute an attractive source of multipotent mesenchymal stem cells owing to their high proliferation rate and multilineage differentiation potential. Osteogenesis is initiated by osteoblasts, which originate from mesenchymal stem cells. These cells express specific surface antigens that disappear gradually during osteodifferentiation. In parallel, the appearance of characteristic markers, including alkaline phosphatase, collagen type I, osteocalcin and osteopontin characterize the osteoblastic phenotype of dental pulp stem cells. This review will shed the light on the osteogenic differentiation potential of dental pulp stem cells and explore the culture medium components, and markers associated with osteodifferentiation of these cells.

Effect of MTA and CEM on Mineralization-Associated Gene Expression in Stem Cells Derived from Apical Papilla

INTRODUCTION

This study assessed the effect of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement on odontogenic differentiation and mineralization of stem cells.

METHODS AND MATERIALS

After confirmation of stemness and homogeneity of stem cells derived from apical papilla (SCAPs) using flow cytometry, the cells were exposed for 3 weeks to either osteogenic medium (OS) or CEM extract+OS (CEM+OS) or MTA extract in OS (MTA+OS) or DMEM based regular culture media (negative control). Relative expression of alkaline phosphatase (ALP), dentine sialophosphoprotein (DSPP), osteocalcin (OSC), and osterix (SP7) were measured at days 14 and 21 using RT-qPCR method. At the same time points Alizarin Red staining method was used to assess mineralization potential of SCAPS. Gene expression changes analysis were made automatically using REST® software and a P<0.05 was considered significant.

RESULTS

After 2 weeks of exposure, expression of all genes were between 3 and 52 times the expression of GADPH (all were upregulated except SP7 in the control, P<0.05). After 3 weeks, relative expressions of the genes: ALP, SP7, DSPP, and OSC were respectively 275.9, 528.3, 98.4, and 603.7 times the expression of GADPH in the control group (OS). These were respectively 17.405, 29.2, 11.8, and 6.5 in CEM+OS group, and 163.8, 119.7, 102.5, and 723.9 in MTA+OS group. All of these were confirmed as upregulated (P<0.05) except for ALP and OSC of DM+CEM group. After 2 weeks, alizarin red staining showed similar mineralized nodules in OS, MTA+OS, and CEM+OS. In third week, larger nodules were seen in MTA+OS and OS, but not in CEM+OS.

CONCLUSION

After 2 weeks, gene expressions were almost comparable in OS, CEM+OS, and MTA+OS. After 3 weeks, OS and MTA+OS upregulated genes much greater than in 2nd week. However, upregulation in CEM+OS might not increase in 3rd week compared to those in 2nd week.

Calcium Phosphate Cement with Antimicrobial Properties and Radiopacity as an Endodontic Material

Calcium phosphate cements (CPCs) have several advantages for use as endodontic materials, and such advantages include ease of use, biocompatibility, potential hydroxyapatite-forming ability, and bond creation between the dentin and appropriate filling materials. However, unlike tricalcium silicate (CS)-based materials, CPCs do not have antibacterial properties. The present study doped a nonwashable CPC with 0.25–1.0 wt % hinokitiol and added 0, 5, and 10 wt % CS. The CPCs with 0.25–0.5 wt % hinokitiol showed appreciable antimicrobial properties without alterations in their working or setting times, mechanical properties, or cytocompatibility. Addition of CS slightly retarded the apatite formation of CPC and the working and setting time was obviously reduced. Moreover, addition of CS dramatically increased the compressive strength of CPC. Doping CS with 5 wt % ZnO provided additional antibacterial effects to the present CPC system. CS and hinokitiol exerted a synergic antibacterial effect, and the CPC with 0.25 wt % hinokitiol and 10 wt % CS (doped with 5 wt % ZnO) had higher antibacterial properties than that of pure CS. The addition of 10 wt % bismuth subgallate doubled the CPC radiopacity. The results demonstrate that hinokitiol and CS can improve the antibacterial properties of CPCs, and they can thus be considered for endodontic applications.

Calcium silicate-based cements and functional impacts of various constituents

Calcium silicate-based cements have superior sealing ability, bioactivity, and marginal adaptation, which make them suitable for different dental treatment applications. However, they exhibit some drawbacks such as long setting time and poor handling characteristics. To overcome these limitations calcium silicates are engineered with various constituents to improve specific characteristics of the base material, and are the focus of this review. An electronic search of the PubMed, MEDLINE, and EMBASE via OVID databases using appropriate terms and keywords related to the use, application, and properties of calcium silicate-based cements was conducted. Two independent reviewers obtained and analyzed the full texts of the selected articles. Although the effects of various constituents and additives to the base Portland cement-like materials have been investigated, there is no one particular ingredient that stands out as being most important. Applying nanotechnology and new synthesis methods for powders most positively affected the cement properties.

Evaluation of cytocompatibility of calcium silicate-based endodontic sealers and their effects on the biological responses of mesenchymal dental stem cells

AIM

To investigate in vitro the cytocompatibility of the calcium silicate-containing endodontic sealers MTA Fillapex and TotalFill BC Sealer on human periodontal ligament stem cells (hPDLSCs) by assaying their biological responses and compare them with that observed when using an epoxy resin-based sealer (AH Plus).

METHODOLOGY

Specimens from the three different endodontic sealers were eluated with culture medium for 24 h. The cytotoxicity of these eluates was evaluated using the MTT assay. In addition, an in vitro scratch wound healing model was used to determine their effects on cell migration. Cell adhesion to collagen type I after treatment with the different sealer eluates was also measured, whereas cytotoxicity was determined using the DNA-specific fluorochrome Hoechst 33342. Finally, to assess cell morphology and attachment to the different sealers, hPDLSCs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). One-way analysis of variance (anova) followed by a Bonferroni post-test were performed (P < 0.05).

RESULTS

hPDLSCs exposed to different dilutions of TotalFill BC Sealer eluates had significantly higher cell proliferation compared with that observed when cells were treated with AH Plus and MTA Fillapex eluates (P < 0.001). In addition, TotalFill eluates were associated with significantly increased cell adhesion to collagen type I and migration of hPDLSCs in a concentration-dependent manner than displayed after treatment with MTA Fillapex or AH Plus eluates (P < 0.001). Moreover, TotalFill BC Sealer-induced cytotoxicity was significantly lower than observed using AH Plus and MTA Fillapex eluates (P < 0.001). Finally, SEM studies revealed suitable proliferation, cell spreading and attachment, especially when using TotalFill BC Sealer discs.

CONCLUSION

TotalFill BC Sealer exhibited a higher cytocompatibility than AH Plus and MTA Fillapex. Further investigations using in vivo animal models are required to validate the potential biological responses of TotalFill BC Sealer on hPDLSCs.

Potential proinflammatory and osteogenic effects of dicalcium silicate particles in vitro

BACKGROUND

Due to their biocompatibility and bioactivity, dicalcium silicate (C2S) and hydroxyapatite (HA) are used as coating materials for prosthetic orthopedic and dental implants or as bone substitute materials to fill bone defects. However, prostheses and bone substitutes can release particles that trigger an immune response in the recipient. The immunological effects of C2S particles have not yet been studied.

OBJECTIVE

The aim of this study was to determine the cytotoxic effects of C2S particles on primary human monocytes, a human monocyte cell line (THP-1) and an osteoblast-like cell line (MG-63). The proinflammatory effects of C2S particles on THP-1 were also detected. Moreover, the osteogenic effects of C2S and HA on MG-63 cells were investigated.

METHODS

Characterization of C2S and HA was performed using scanning electron microscopy (SEM), energy dispersive analysis (EDS), X-ray diffraction (XRD), Brunner-Emmett-Teller (BET) measurements and laser diffraction. The cytotoxic effect of C2S on primary human monocytes as well as THP-1 and MG-63 cells was measured using Trypan blue assays, Cell Counting Kit-8 (CCK-8) assays and flow cytometry to detect apoptosis. THP-1 human monocytes with or without lipopolysaccharide (LPS) stimulation were exposed to C2S and HA for 6 and 24h. Thereafter, the mRNA expression and protein concentrations of MMP-2, MMP-9, TIMP-2, TIMP-1 and TNF-α were evaluated using real-time PCR and ELISA, respectively. RANKL and OPG mRNA expression levels in MG-63 cells were examined using real-time PCR.

RESULTS

No significant cytotoxicity was recorded when cells were directly cultured with C2S/HA particles. After THP-1 cells were cultured with C2S/HA for 24h, MMP-2, MMP-9 and TNF-α expression increased, whereas TIMP-2 and TIMP-1 expression decreased. Compared with HA, C2S slightly increased MMP-9 expression and slightly decreased TIMP-1 expression. The MMP: TIMP ratio increased in the C2S and HA groups; however, HA significantly increased the MMP-9: TIMP-1 ratio compared with C2S. Compared with HA, C2S caused less TNF-α production. C2S/HA did not modify the expression of proinflammatory mediators in LPS-stimulated cells. Furthermore, C2S/HA significantly increased OPG expression and slightly increased RANKL expression in MG-63 cells. C2S and HA decreased the RANKL: OPG ratio.

CONCLUSION

Our in vitro data suggest that C2S is relatively safe when directly cultured with cells. In addition, C2S may exert proinflammatory effects; however, compared with HA, C2S had fewer proinflammatory effects on THP-1. C2S and HA did not alter the LPS-induced production of proinflammatory mediators and had similar osteogenic effects on MG-63 cells.

Physicochemical properties and osteogenic activity of radiopaque calcium silicate-gelatin cements

The purpose of this study is to evaluate the physicochemical properties and in vitro osteogenic activity of radiopaque calcium silicate-gelatin cements. The radiopacity, setting time, working time, flow, diametral tensile strength, pH value, washout resistance and morphology of the cements with gelatin (0, 5 and 10% by weight) were measured, which compared to a popular endodontic material, ProRoot white-colored mineral trioxide aggregate (WMTA). The cell morphology, cell attachment and proliferation, alkaline phosphatase and osteocalcin levels on the cements were measured by culturing the specimens with dental pulp cells. The results indicated that the presence of gelatin significantly (P < 0.05) reduced radiopacity and diametral tensile strength and prolonged setting time. Nevertheless, the 5 wt% gelatin cement had a radiopacity (5.1 mm of Al thickness) higher than ISO 6876:2001 standards (3 mm of Al thickness). The setting time (33 min), working time (9 min) and flow value (17.4 mm) of the 5 wt% gelatin cement were significantly (P < 0.05) better than those of WMTA (corresponding 165, 6 min and 14.2 mm). The fresh WMTA completely degraded after soaking in a physiological solution for 1 h, while the gelatin cements resisted washout, showing no noticeable breakdown even after 1 day of soaking. The gelatin cement enhanced the higher expression of cell attachment, proliferation and differentiation as compared to WMTA. It was concluded that the 5 wt% gelatin-calcium silicate hybrid cement appears to be promising as a radiopaque biomaterial for medical applications such as endodontics and vertebroplasty.

Comparative cell attachment, cytotoxicity and antibacterial activity of radiopaque dicalcium silicate cement and white-coloured mineral trioxide aggregate

AIM

To comparatively examine the cell attachment, cytotoxicity, and antibacterial activity of radiopaque dicalcium silicate cement (RDSC) and ProRoot white-coloured mineral trioxide aggregate (WMTA).

METHODOLOGY

AlamarBlue was used for real-time and repeated monitoring of MG63 cell attachment on freshly mixed and set cements. The pH changes in the growth medium at different time-points were also measured. Cytotoxicity evaluation was performed according to ISO 10993-5 specifications. The antibacterial activity of the cement specimens was evaluated using Enterococcus faecalis.

RESULTS

There were no significant differences (P > 0.05) between the two cements for cell attachment either in the fresh groups or in the set groups at all culture times. Neither freshly mixed group nor set groups had significant pH differences. In the case of cytotoxicity, RDSC was significantly (P < 0.05) superior to WMTA at 12 and 24 h of incubation. RDSC and WMTA possessed similar antimicrobial activity, substantiated by the formation of growth inhibition zones and bacteriostasis ratio in E. faecalis strains.

CONCLUSIONS

The cell attachment, cytotoxicity and antibacterial efficacy of RDSC were comparable to those reported for ProRoot WMTA. The results of the current study suggest that this RDSC could be used as a root-end filling material and root sealer.

Effect of verapamil, a calcium channel blocker, on the odontogenic activity of human dental pulp cells cultured with silicate-based materials

INTRODUCTION

This study examines how calcium silicate cement extracts influence the behavior of human dental pulp cells (hDPCs) through calcium channels and active mitogen-activated protein kinase pathways, in particular extracellular signal-related kinase (ERK).

METHODS

HDPCs are treated with various silicon concentrations both with and without verapamil, after which the cells' viability and odontogenic differentiation markers are determined by using PrestoBlue assay and Western blot, respectively.

RESULTS

The silicon promoted cell proliferation and inhibited calcium channel blockers. It was also found that silicon increased ERK and p38 activity in a dose-dependent manner. Furthermore, it raised the expression and secretion of alkaline phosphatase, osteocalcin, dentin sialophosphoprotein, and dentin matrix protein-1. In addition, statistically significant differences (P < .05) have been found in the secretion of osteocalcin in ERK inhibitor + verapamil between the silicon concentrations; these varations are dose-dependent and indicate that ERK signaling is involved in the silicon-induced odontogenic differentiation of hDPCs.

CONCLUSIONS

The current study shows that silicon ions released from calcium silicate substrates play a key role in odontoblastic differentiation of hDPCs through calcium channels and modulate ERK activation.

Rational design and fabrication of a β-dicalcium silicate-based multifunctional cement with potential for root canal filling treatment

Gypsum-introduced, CaO-rich dicalcium silicate-based cements exhibit multifunctional physicochemical and biological properties and meet some challenging criteria in root canal therapy.

Comparative Osteogenesis of Radiopaque Dicalcium Silicate Cement and White-Colored Mineral Trioxide Aggregate in a Rabbit Femur Model

The radiopaque dicalcium silicate cement (RDSC) displayed a shortened setting time and good biocompatibility. This study aimed to compare the regenerative potential of RDSC and white-colored mineral trioxide aggregate (WMTA) using a rabbit femur model. The animals were sacrificed at one, three and six months to accomplish histological and biochemical analyses. The results indicated that after one month of implantation, WMTA was associated with a greyish color alteration within its mass, while RDSC presented color stability even at six months. Histological assay with Masson's Trichrome and Von Kossa stains showed the presence of newly formed bone surrounding the implanted sites in the rabbit femur. The histochemical data revealed that the RDSC group had significantly more bone regeneration than did the WMTA groups at three and six months. The conclusion drawn is that the encouraging results support the potential applications of RDSC as an improved alternative to WMTA for endodontic uses.

Integrin binding and MAPK signal pathways in primary cell responses to surface chemistry of calcium silicate cements

Cell attachment, proliferation and differentiation on different materials depend largely on the surface properties of the materials. This study sheds light on the mechanism by which the modulation of the chemical composition of calcium silicate cements with different Si/Ca molar ratios could produce different cell responses. Two primary cell types (human mesenchymal stem cells (hMSCs) and human dental pulp cells (hDPCs)) were used to elicit the changes in total DNA content, integrin subunit levels, phosphor-focal adhesion kinase (pFAK) levels, and mitogen-activated protein kinase (MAPK) signaling pathway activity at the cell attachment stage. The effect of small interfering RNA (siRNA) transfection targeting collagen type I (COL I) and fibronectin (FN) was also evaluated. The results indicated that increased total DNA content, pFAK and total integrin levels were observed upon an increase in cement Si content. Cements with different Si/Ca ratios did not cause the variations of interleukin 1β (IL-1β), epidermal growth factor (EGF) and tumor necrosis factor-α (TNF-α) ligands. The Si-rich cement facilitated COL I and α2β1 subintegrin expression, while Ca-rich cement promoted FN and αvβ3 subintegrin expression. Si component of the calcium silicates stimulated cell adhesion via activation of MAPK/extracellular signal-regulated kinase (ERK) and p38 signaling pathways more effectively than did by Ca component, but it did not affect c-Jun NH2-terminal kinase (JNK) activity. Inhibition of MAPK/ERK and MAPK/p38 signaling pathways in hMSCs and hDPCs significantly attenuated adhesion, proliferation and differentiation as assessed according to total DNA content and alkaline phosphatase activity. hMSCs and hDPCs from the three different donors exhibited a similar preference for cell behaviors. The results of the current study suggest that calcium silicate cements with a higher Si content have the potential to serve as excellent supports for primary cells. Unraveling the mechanism by which primary cells responded to calcium silicate materials will be beneficial for materials design in their eventual clinical use.

In vitro physicochemical properties, osteogenic activity, and immunocompatibility of calcium silicate-gelatin bone grafts for load-bearing applications

The use of a composite made of natural polymer gelatin and bioactive calcium silicate resembling the morphology and properties of natural bone may provide a solution to the problem of ceramic brittleness for load-bearing applications. The in vitro bioactivity, degradability, osteogenic activity, and immunocompatibility of three types of calcium silicate-gelatin composite bone grafts were characterized. The osteogenic activity and immunocompatibility were evaluated by incubating the bone grafts with human dental pulp cells. After soaking in a simulated body fluid (SBF) for 1 day, all materials were covered with clusters of "bone-like" apatite spherulites. The control material without gelatin exhibited an insignificant change in strength, degradability, and porosity and a small weight loss of 6% after 180 days of soaking in the SBF solution. In contrast, the soaking time imposed in this study did have a statistically significant effect on compressive strength, porosity, and weight loss of the gelatin-containing composites. After 180 days of soaking, the composite with 10 wt % gelatin lost 47% and 10% in compressive strength and weight, respectively, with a porosity of 23%. However, the presence of gelatin promoted greater cell attachment and proliferation on the composite bone grafts. Pulp cells on the calcium silicate-gelatin bone grafts expressed higher levels of osteocalcin, osteopontin, and bone sialoprotein. The inhibition of inducible nitric oxide synthase and interleukin-1 expression and the activation of interleukin-10 were increased with increasing gelatin content. Overall, these findings provide evidence that composite bone grafts containing 10 wt % gelatin with a high initial strength were bioactive, nontoxic, and osteogenic and may be able to promote bone healing for load-bearing applications.