Effect of an Experimental Direct Pulp-capping Material on the Properties and Osteogenic Differentiation of Human Dental Pulp Stem Cells

Effect of pulp capping materials on odontogenic differentiation of human dental pulp stem cells: An in vitro study

OBJECTIVES

Migration and differentiation of human dental pulp stem cells (hDPSCs) is a vital and key factor in the success of reparative dentin formation for maintenance of pulp vitality. Pulp capping materials are used to stimulate DPSCs to induce new dentin formation. Thus, the aim of the present study was to compare the response of DPSCs to four commercially available pulp capping materials: a bioactive bioceramic (Material 1), a nonresinous ready-to-use bioceramic cement (Material 2), a bioactive composite (Material 3), and a biocompatible, dual-cured, resin-modified calcium silicate (Material 4).

MATERIALS AND METHODS

hDPSCs were isolated and cultured from freshly extracted teeth and were then characterized by flow cytometry and multilineage differentiation. Discs prepared from pulp capping materials were tested with hDPSCs and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell migration assay and odontogenic differentiation assay was performed. Expression of osteogenic markers (osteopontin, RUNX family transcription factor 2, osteocalcin) and the odontogenic marker (dentin sialophosphoprotein) was detected using reverse transcription-polymerase chain reaction.

RESULTS

Materials 1, 2, and 3 generated more cell viability than Material 4. Furthermore, Material 4 showed the least wound exposure percentage, while Material 3 showed the highest percentage. Enhanced mineralization was found in hDSCPs cultured with Material 3, followed by Material 1, and then Material 2, while Material 4 revealed the least calcified mineralization.

CONCLUSIONS

The results of this study were inconclusive regards contemporary bioceramic materials designed for vital pulp therapy as they have different effects on hDPSC. Further testing for cytotoxicity using live-dead staining, animal experiments, clinical trials, and independent analyses of these biomaterials is necessary for clinicians to make an informed decision for their use.

Applications of quaternary ammonium compounds in the prevention and treatment of oral diseases: State-of-the-art and future directions

OBJECTIVES

The aim of this review is to comprehensively summarize the state-of-the-art developments of quaternary ammonium compounds (QACs) in the prevention and treatment of oral diseases. By discussing the structural diversity and the potential killing mechanism, we try to offer some insights for the future research of QACs.

DATA, SOURCES & STUDY SELECTION

A literature search was conducted in electronic databases (Web of Science, PubMed, Medline, and Scopus). Publications that involved the applications of QACs, especially those related to the prevention and treatment of oral diseases, are included.

RESULTS

We have reviewed the relevant research on QACs over the past two decades. The research results indicate that the current applications are mainly focused on dental material modification and direct pharmacological interventions. Concurrently, challenges such as potential risks to normal tissues and impediments in drug resistance and microbial persistence present certain application constraints. The latest studies have encompassed the exploration of smart materials and nanoparticle formulations.

CONCLUSIONS

The killing mechanism may possess a threshold related to charge density. However, the exact process remains enigmatic. The structural diversity and the exploration of intelligent materials and nanoparticle formulations provide directions in development of novel QACs.

CLINICAL SIGNIFICANCE

The intricate oral anatomy, combined with the multifaceted oral microbiome, necessitates specialized materials for the targeted prevention and treatment of oral pathologies. QACs represent a cohort of compounds distinguished by potent anti-infective and anti-tumor attributes. Innovations in intelligent materials and nanoparticle formulations amplify their potential in significantly advancing the prevention and therapeutic interventions for oral diseases.

Comparative Biocompatibility and Odonto-/Osteogenesis Effects of Hydraulic Calcium Silicate-Based Cements in Simulated Direct and Indirect Approaches for Regenerative Endodontic Treatments: A Systematic Review

BACKGROUND

Regenerative dentistry is the operation of restoring dental, oral and maxillofacial tissues. Currently, there are no guidelines for the ideal cement/material in regenerative endodontic treatments (RET). Hydraulic calcium silicate-based cements (hCSCs) are currently the material of choice for RET.

OBJECTIVES

This systematic review was conducted to gather all of the different direct and indirect approaches of using hCSCs in RET in vitro and in vivo, and to ascertain if there are any superiorities to indirect approaches.

METHODS AND MATERIALS

This systematic review was conducted according to the 2020 PRISMA guidelines. The study question according to the PICO format was as follows: Comparison of the biological behavior (O) of stem cells (P) exposed to hCSCs through direct and indirect methods (I) with untreated stem cells (C). An electronic search was executed in Scopus, Google Scholar, and PubMed.

RESULTS

A total of 78 studies were included. Studies were published between 2010 and 2022. Twenty-eight commercially available and eighteen modified hCSCs were used. Seven exposure methods (four direct and three indirect contacts) were assessed. ProRoot MTA and Biodentine were the most used hCSCs and had the most desirable results. hCSCs were either freshly mixed or set before application. Most studies allowed hCSCs to set in incubation for 24 h before application, which resulted in the most desirable biological outcomes. Freshly mixed hCSCs had the worst outcomes. Indirect methods had significantly better viability/proliferation and odonto-/osteogenesis outcomes.

CONCLUSION

Biodentine and ProRoot MTA used in indirect exposure methods result in desirable biological outcomes.

Host defense peptides combined with MTA extract increase the repair in dental pulp cells: in vitro and ex vivo study

Host Defense Peptides (HDPs) have, in previous studies, been demonstrating antimicrobial, anti-inflammatory, and immunomodulatory capacity, important factors in the repair process. Knowing these characteristics, this article aims to evaluate the potential of HDPs IDR1018 and DJK-6 associated with MTA extract in the repair process of human pulp cells. Antibacterial activity of HDPs, MTA and HDPs combined with MTA in Streptococcus mutans planktonic bacteria and antibiofilm activity was evaluated. Cell toxicity was assayed with MTT and cell morphology was observed by scanning electron microscopy (SEM). Proliferation and migration of pulp cells were evaluated by trypan blue and wound healing assay. Inflammatory and mineralization related genes were evaluated by qPCR (IL-6, TNFRSF, DSPP, TGF-β). Alkaline phosphatase, phosphate quantification and alizarin red staining were also verified. The assays were performed in technical and biological triplicate (n = 9). Results were submitted for the calculation of the mean and standard deviation. Then, normality verification by Kolmogorov Smirnov test, analyzing one-way ANOVA. Analyses were considered at a 95% significance level, with a p-value < 0.05. Our study demonstrated that HDPs combined with MTA were able to reduce biofilms performed in 24 h and biofilm performed over 7 days S. mutans biofilm (p < 0.05). IDR1018 and MTA, as well as their combination, down-regulated IL-6 expression (p < 0.05). Tested materials were not cytotoxic to pulp cells. IDR1018 induced high cell proliferation and combined with MTA induced high cellular migration rates in 48 h (p < 0.05). Furthermore, the combination of IDR1018 and MTA also induced high expression levels of DSPP, ALP activity, and the production of calcification nodules. So, IDR-1018 and its combination with MTA could assist in pulp-dentine complex repair process in vitro.

Bioinductive and anti-inflammatory properties of Propolis and Biodentine on SHED

Objectives

This study aimed to evaluate and compare the cell viability, differentiation potential and anti-inflammatory potential of propolis and Biodentine™ on stem cells isolated from human exfoliated deciduous teeth (SHED).

Materials and methods

SHED were segregated and cultured from the dental pulp of children after therapeutic extraction. Microculture Tetrazolium Assay (MTT) assay was carried out for assessing cell proliferation potential of propolis and Biodentine at different concentrations. As per the results from cell proliferation assay, cell differentiation potential of SHED was evaluated at concentration of 12.5 μg/ml using Alizarin Red staining. The anti-inflammatory potential of test materials was evaluated using gelatin zymography by detecting MMP-2 and MMP-9.

Results

The maximum cell proliferation percentage of SHED treated with propolis and Biodentine was observed at a concentration of 12.5 μg/ml, on day 7, 14 and 21 with Biodentine having maximum cell proliferation potential followed by propolis. SHED treated with Biodentine showed maximum cell differentiation on day 7 (107.16), 14 (106.29) and 21 (107.72). However, anti-inflammatory activity against MMP-2 was 95 % with propolis and 85 % with Biodentine and whereas, against MMP-9 it was 65 % for propolis and 47 % for Biodentine.

Conclusion

Propolis shows comparable cell viability, cell proliferation and differentiation potential on SHED when compared to Biodentine. It also exhibits better invitro anti-inflammatory activity on SHED compared to Biodentine. Further studies are warranted to validate the application of propolis as an effective and economical alternative biocompatible agent to Biodentine for vital pulp therapies.

Multifunctional Ca-Zn-Si-based micro-nano spheres with anti-infective, anti-inflammatory, and dentin regenerative properties for pulp capping application

While pulp capping using a variety of materials has been applied clinically to preserve the health and vitality of the dental pulp and induce dentin repair no material meets all the anti-infection, anti-inflammation, and promoting pulp tissue regeneration criteria. Micro-nano materials of bioactive glasses (BG) with the biocompatibility and osteogenesis-promoting properties were developed for this study using Zn-doped bioactive glass (BGz) micro-nano spheres for dental pulp capping to control infection and inflammation and promote tissue regeneration. Of three key findings, the co-culture of Porphyromonas gingivalis showed that the BGz had an excellent antibacterial effect, and after being stimulated with BGz in vitro, macrophages showed a significant decrease of pro-inflammatory M1 markers compared with the undoped BG group. It is also noted that the conditioned medium derived from BGz-stimulated macrophages could significantly promote mineralized dentin formation of dental pulp cells (DPCs). In rats, acute pulp restoration experiments proved that BGz used as a pulp capping agent had excellent dentin regenerative properties. This work may provide a novel strategy to promote osteo/dentinogenic differentiation through regulating early inflammation, with potential applications in pulp capping.

Chitosan-Based Accelerated Portland Cement Promotes Dentinogenic/Osteogenic Differentiation and Mineralization Activity of SHED

Calcium silicate-based cements (CSCs) are widely used in various endodontic treatments to promote wound healing and hard tissue formation. Chitosan-based accelerated Portland cement (APC-CT) is a promising and affordable material for endodontic use. This study investigated the effect of APC-CT on apoptosis, cell attachment, dentinogenic/osteogenic differentiation and mineralization activity of stem cells from human exfoliated deciduous teeth (SHED). APC-CT was prepared with various concentrations of chitosan (CT) solution (0%, 0.625%, 1.25% and 2.5% (w/v)). Cell attachment was determined by direct contact analysis using field emission scanning electron microscopy (FESEM); while the material extracts were used for the analyses of apoptosis by flow cytometry, dentinogenic/osteogenic marker expression by real-time PCR and mineralization activity by Alizarin Red and Von Kossa staining. The cells effectively attached to the surfaces of APC and APC-CT, acquiring flattened elongated and rounded-shape morphology. Treatment of SHED with APC and APC-CT extracts showed no apoptotic effect. APC-CT induced upregulation of DSPP, MEPE, DMP-1, OPN, OCN, OPG and RANKL expression levels in SHED after 14 days, whereas RUNX2, ALP and COL1A1 expression levels were downregulated. Mineralization assays showed a progressive increase in the formation of calcium deposits in cells with material containing higher CT concentration and with incubation time. In conclusion, APC-CT is nontoxic and promotes dentinogenic/osteogenic differentiation and mineralization activity of SHED, indicating its regenerative potential as a promising substitute for the commercially available CSCs to induce dentin/bone regeneration.

Biological Characteristics and Odontogenic Differentiation Effects of Calcium Silicate-Based Pulp Capping Materials

We compared calcium silicate-based pulp capping materials to conventional calcium hydroxide in terms of their biological properties and potential effects on odontogenic differentiation in human dental pulp stem cells (hDPSCs). We cultured hDPSCs on disks (7-mm diameter, 4-mm high) of ProRoot MTA (Dentsply Tulsa Dental Specialties), Biodentine (Septodont), TheraCal LC (Bisco), or Dycal (Dentsply Tulsa Dental Specialties). Cell viability was assessed with cell counting (CCK) and scanning electron microscopy (SEM). Odontogenic activity was assessed by measuring alkaline phosphatase (ALP) activity and gene expression (quantitative real-time PCR). CCK assays showed that Dycal reduced cell viability compared to the other materials (p < 0.05). SEM showed low and absent cell attachment on TheraCal LC and Dycal disks, respectively. hDPSCs exposed to TheraCal LC and Dycal showed higher ALP activity on day 6 than the control group (p < 0.05). The day-9 Runx2 expression was higher in the ProRoot MTA and TheraCal LC groups than in the control group (p < 0.05). On day 14, the ProRoot MTA group showed the highest dentin sialophosphoprotein levels (not significant; p > 0.05). In conclusion, various pulp capping materials, except Dycal, exhibited biological properties favorable to hDPSC viability. ProRoot MTA and TheraCal LC promoted higher Runx2 expression than Biodentine. Future studies should explore the odontogenic potential of pulp capping materials.

Differential Gene Expression Changes in Human Primary Dental Pulp Cells Treated with Biodentine and TheraCal LC Compared to MTA

This study aimed to analyze the effects of pulp capping materials on gene expression changes in primary tooth-derived dental pulp cells using next-generation sequencing. Dental pulp cells were extracted and treated with mineral trioxide aggregate (MTA), Biodentine (BD), or TheraCal LC (TC). Cell viability assays were performed. Total RNA was extracted and analyzed through mRNA sequencing. Bioinformatic analysis of differential gene expression in dental pulp cells exposed to BD or TC versus MTA was performed. MTA, BD, and TC exposure had no significant effect on pulp cell viability (p > 0.05). Gene sets associated with inflammatory response (p = 2.94 × 10⁻⁵) and tumor necrosis factor alpha (TNF-α) signaling via the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway (p = 2.94 × 10⁻⁵) were enriched in all materials. In BD-treated cells, Wnt/β-catenin signaling (p = 3.15 × 10⁻⁴) gene sets were enriched, whereas enrichment of interferon gamma (IFN-γ) response (p = 3 × 10⁻³) was observed in TC-treated cells. In gene plot analysis, marked increases in receptor activator of nuclear factor kappa-Β ligand (RANKL) expression were seen in TC-treated cells over time. Despite the similar cell viabilities exhibited among MTA-, BD-, and TC-treated cells, patterns of gene networks differed, suggesting that diverse functional gene differences may be associated with treatment using these materials.

Biocompatibility and Bioactivity of Set Direct Pulp Capping Materials on Human Dental Pulp Stem Cells

In this study, we assessed the biocompatibility and bioactivity of various pulp capping materials—ProRoot MTA (Dentsply Tulsa Dental Specialties), Biodentine (Septodont), TheraCal LC (Bisco), and Dycal (Dentsply Caulk)—on human dental pulp stem cells (hDPSCs). Experimental disks (diameter, 7 mm; height, 4 mm) were stored in a humified incubator at 37 °C for 48 h. Then, the pulp capping materials were tested for cytotoxic effects by methyl-thiazoldiphenyl-tetrazolium and scratch wound healing assays, and for mineralization potential by Alizarin red S (ARS) staining assay and alkaline phosphatase enzyme (ALP) activity. Cell viability and cell migration did not significantly differ between ProRoot MTA, Biodentine, and control (p > 0.05). TheraCal LC exhibited slower cell migration on days 2–4 compared to control (p < 0.05), and Dycal showed no cell migration. ALP activity was highest with Biodentine on days 10 and 14, and was lowered with TheraCal LC and Dycal (p < 0.05). In the ARS assay, hDPSCs grown in ProRoot MTA and TheraCal LC eluates showed significantly increased mineralized nodule formation on day 21 compared to Biodentine, Dycal, and control (p < 0.05). These findings indicate that ProRoot MTA, Biodentine, and TheraCal LC exhibit better biocompatibility and bioactivity than Dycal.

LncRNA H19 promotes odontoblastic differentiation of human dental pulp stem cells by regulating miR-140-5p and BMP-2/FGF9

BACKGROUND

Increasing evidence has revealed that long non-coding RNAs (lncRNAs) exert critical roles in biological mineralization. As a critical process for dentin formation, odontoblastic differentiation is regulated by complex signaling networks. The present study aimed to investigate the biological role and regulatory mechanisms of lncRNA-H19 (H19) in regulating the odontoblastic differentiation of human dental pulp stem cells (hDPSCs).

METHODS

We performed lncRNA microarray assay to reveal the expression patterns of lncRNAs involved in odontoblastic differentiation. H19 was identified and verified as a critical factor by qRT-PCR. The gain- and loss-of-function studies were performed to investigate the biological role of H19 in regulating odontoblastic differentiation of hDPSCs in vitro and in vivo. Odontoblastic differentiation was evaluated through qRT-PCR, Western blot, and Alizarin Red S staining. Bioinformatics analysis identified that H19 could directly interact with miR-140-5p, which was further verified by luciferase reporter assay. After overexpression of miR-140-5p in hDPSCs, odontoblastic differentiation was determined. Moreover, the potential target genes of miR-140-5p were investigated and the biological functions of BMP-2 and FGF9 in hDPSCs were verified. Co-transfection experiments were conducted to validate miR-140-5p was involved in H19-mediated odontoblastic differentiation in hDPSCs.

RESULTS

The expression of H19 was significantly upregulated in hDPSCs undergoing odontoblastic differentiation. Overexpression of H19 stimulated odontoblastic differentiation in vitro and in vivo, whereas downregulation of H19 revealed the opposite effect. H19 binds directly to miR-140-5p and overexpression of miR-140-5p inhibited odontoblastic differentiation of hDPSCs. H19 acted as a miR-140-5p sponge, resulting in regulated the expression of BMP-2 and FGF9. Overexpression of H19 abrogated the inhibitory effect of miR-140-5p on odontoblastic differentiation.

CONCLUSION

Our data revealed that H19 plays a positive regulatory role in odontoblastic differentiation of hDPSCs through miR-140-5p/BMP-2/FGF9 axis, suggesting that H19 may be a stimulatory regulator of odontogenesis.

microRNA-143-3p regulates odontogenic differentiation of human dental pulp stem cells through regulation of the osteoprotegerin-RANK ligand pathway by targeting RANK

NEW FINDINGS

What is the central question of this study? What is the role of miR-143-3p during human dental pulp stem cell (hDPSC) differentiation. What is the main finding and its importance? miR-143-3p negatively regulates receptor activator of nuclear factor-κB (RANK). RANK ligand (RANKL) binds to RANK and stimulates the development of osteoclasts. Osteoprotegerin (OPG) inhibits the interaction between RANK and RANKL. The OPG-RANKL signalling pathway regulates odontogenic differentiation of hDPSCs.

ABSTRACT

Human dental pulp stem cells (hDPSCs) are capable of differentiating into odontoblast-like cells, which secrete reparative dentin after injury, in which the role of microRNA-143-3p (miR-143-3p) has been identified. Therefore, we investigated the mechanism by which miR-143-3p influences odontoblastic differentiation of hDPSCs. The relationship between miR-143-3p and receptor activator of nuclear factor-κB (RANK) was initially identified by bioinformatics prediction and further verified by dual luciferase reporter gene assay. Gain- and loss-of-function analysis with miR-143-3p mimic and miR-143-3p inhibitor was subsequently conducted. Dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), alkaline phosphatase (ALP), osteocalcin (OCN) and osteopontin (OPN) mRNA levels were then evaluated by RT-qPCR. Osteoprotegerin (OPG), RANK ligand (RANKL), nuclear factor-κB (NF-κB) p65 protein levels and the extent of NF-κB p65 phosphorylation were examined by western blot analysis. Alizarin red staining was performed to assess the mineralization of hDPSCs. Cell apoptosis and cell cycle distribution were determined using flow cytometry. During odontoblastic differentiation of hDPSC, miR-143-3p had high expression, but RANK expression was low. miR-143-3p was found to target RANK, and its inhibition enhanced mineralization and hDPSC apoptosis, while blocking cell cycle entry. At the same time, miR-143-3p inhibition elevated the extent of NF-κB p65 phosphorylation, as well as the expression of RANK, RANKL, DSPP, BSP, ALP, OCN and OPN, while decreasing the OPG level. Silencing RANK had opposite effects on these markers. miR-143-3p regulates odontoblastic differentiation of hDPSCs via the OPG-RANKL pathway that targets RANK. The elucidation of the mechanisms of odontogenic differentiation of hDPSCs may contribute to the development of effective dental pulp repair therapies for the clinical setting.

Response of stem cells from human exfoliated deciduous teeth (SHED) to three bioinductive materials - An in vitro experimental study

Introduction

Stem cells have unmatched capacity and potential for regeneration and when used alone or in combination with scaffolds to replace or repair damaged cells, can differentiate into any mature cell.

Aim

To evaluate the functional differentiation potential of EMD (Enamel Matrix Derivative), MTA (Mineral Trioxide Aggregate) and Biodentine on Stem Cells from Human Exfoliated Deciduous teeth (SHED).

Objective

To determine functional differentiation potential (osteogenic/odontogenic) of various biomaterials on SHED.

Material and method

SHED derived from 5^th linear passage after sub-culturing were treated with EMD, MTA and Biodentine individually and their effect on cell viability was compared and evaluated by MTT (3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide) assay for 7 days. Alizarin red S staining was used to assess mineralization potential of these materials by the staining calcium deposits for 14 days. The results were analyzed using One-way ANOVA, Post hoc Tukey’s test for multiple comparisons.

Results

It was observed that EMD imparted the highest cell viability at the end of 7 days (p < 0.001) followed by Biodentine and MTA. Likewise EMD showed highest potential to enhanced mineralization and expression of dentine sialoprotein (p < 0.001) followed by Biodentine and MTA at the end of 14 days (p<0.001).

Conclusion

It can be concluded that all the tested materials are bioinductive to SHED. EMD can be used for various vital pulp therapies as that of Biodentine and MTA with predictable as well as enhanced success rate.

Automated digital image quantification of histological staining for the analysis of the trilineage differentiation potential of mesenchymal stem cells

BACKGROUND

Multipotent mesenchymal stem cells (MSCs) have the potential to repair and regenerate damaged tissues and are considered as attractive candidates for the development of cell-based regenerative therapies. Currently, there are more than 200 clinical trials involving the use of MSCs for a wide variety of indications. However, variations in their isolation, expansion, and particularly characterization have made the interpretation of study outcomes or the rigorous assessment of therapeutic efficacy difficult. An unbiased characterization of MSCs is of major importance and essential to guaranty that only the most suitable cells will be used. The development of standardized and reproducible assays to predict MSC potency is therefore mandatory. The currently used quantification methodologies for the determination of the trilineage potential of MSCs are usually based on absorbance measurements which are imprecise and prone to errors. We therefore aimed at developing a methodology first offering a standardized way to objectively quantify the trilineage potential of MSC preparations and second allowing to discriminate functional differences between clonally expanded cell populations.

METHOD

MSCs originating from several patients were differentiated into osteoblasts, adipocytes, and chondroblasts for 14, 17, and 21 days. Differentiated cells were then stained with the classical dyes: Alizarin Red S for osteoblasts, Oil Red O for adipocytes, and Alcian Blue 8GX for chondroblasts. Quantification of differentiation was then performed with our newly developed digital image analysis (DIA) tool followed by the classical absorbance measurement. The results from the two techniques were then compared.

RESULT

Quantification based on DIA allowed highly standardized and objective dye quantification with superior sensitivity compared to absorbance measurements. Furthermore, small differences between MSC lines in the differentiation potential were highlighted using DIA whereas no difference was detected using absorbance quantification.

CONCLUSION

Our approach represents a novel method that simplifies the laboratory procedures not only for the quantification of histological dyes and the degree of differentiation of MSCs, but also due to its color independence, it can be easily adapted for the quantification of a wide range of staining procedures in histology. The method is easily applicable since it is based on open source software and standard light microscopy.

The Relationship of Surface Characteristics and Antimicrobial Performance of Pulp Capping Materials

INTRODUCTION

Pulp capping materials need to be able to protect the pulp but also bond to the overlying restorative materials. Light-curable pulp capping materials bond better to restorative materials and are easier to place than most water-based cements. The aim of this study was to characterize new light-curable tricalcium silicate-based pulp capping materials and compare their surface and antimicrobial properties with clinically available Theracal (Bisco, Schaumburg, IL) and Biodentine (Septodont, Saint-Maur-des-Fossés, France).

METHODS

The surface characteristics of 3 light-curable pulp capping materials based on a resin and filled with tricalcium silicate and tantalum oxide radiopacifier and Theracal and Biodentine were assessed by scanning electron microscopy, X-ray diffraction, and contact angle measurement. The radiopacity was measured following ISO 6876 standards. The antimicrobial activity was determined by the direct contact test and the antibiofilm activity by the adenosine triphosphate assay and the confocal laser scanning Live/Dead assay (Invitrogen, Eugene, OR) using a polymicrobial culture.

RESULTS

The surface characteristics of the materials varied with the unfilled resin and Biodentine exhibiting a hydrophobic surface. Biodentine showed significantly higher antimicrobial properties in the direct contact test, but this property was absent in the antibiofilm activity tests. The resins filled with tricalcium silicate and Theracal showed higher antimicrobial activity than Biodentine in the adenosine triphosphate and live/dead assays.

CONCLUSIONS

The surface characteristics of a material affect its antimicrobial properties. The experimental resin-modified materials exhibited comparable antimicrobial properties with other light-curable pulp capping agents. Further long-term studies on the materials' antimicrobial activity are required to assess whether they can result in better clinical outcomes.

Therapeutic effects of hepatocyte growth factor-overexpressing dental pulp stem cells on liver cirrhosis in a rat model

Cirrhosis is the terminal stage of hepatic diseases and is prone to develop into hepatocyte carcinoma. Increasing evidence suggests that the transplantation of dental pulp stem cells (DPSCs) may promote recovery from cirrhosis, but the key regulatory mechanisms involved remain to be determined. In this study, we overexpressed human hepatocyte growth factor (hHGF) in primary rat DPSCs and evaluated the effects of HGF overexpression on the biological behaviors and therapeutic efficacy of grafted DPSCs in cirrhosis. Liver cirrhosis was induced via the intraperitoneal injection of CCl₄ twice weekly for 12 weeks and was verified through histopathological and serological assays. HGF was overexpressed in DPSCs via transduction with a hHGF-lentiviral vector and confirmed based on the elevated expression and secretion of HGF. The HGF-overexpressing DPSCs were transplanted into rats intravenously. The HGF-overexpressing DPSCs showed increased survival and hepatogenic differentiation in host liver tissue at 6 weeks after grafting. They also exhibited a significantly greater repair potential in relation to cirrhosis pathology and impaired liver function than did DPSCs expressing HGF at physiological levels. Our study may provide an experimental basis for the development of novel methods for the treatment of liver cirrhosis in clinical practice.

Biocompatibility of New Pulp-capping Materials NeoMTA Plus, MTA Repair HP, and Biodentine on Human Dental Pulp Stem Cells

INTRODUCTION

The aim of the present study was to evaluate the in vitro cytotoxicity of MTA Repair HP, NeoMTA Plus, and Biodentine, new bioactive materials used for dental pulp capping, on human dental pulp stem cells (hDPSCs).

METHODS

Biological testing was carried out in vitro on hDPSCs. Cell viability and cell migration assays were performed using eluates of each capping material. To evaluate cell morphology and cell attachment to the different materials, hDPSCs were directly seeded onto the material surfaces and analyzed by scanning electron microscopy. The chemical composition of the pulp-capping materials was determined by energy-dispersive X-ray and eluates were analyzed by inductively coupled plasma-mass spectrometry. Statistical differences were assessed by analysis of variance and Tukey test (P < .05).

RESULTS

Cell viability was moderate after 24 and 48 hours in the presence of MTA Repair HP and NeoMTA Plus, whereas at 48 and 72 hours, Biodentine showed higher rates of cell viability than MTA Repair HP and NeoMTA Plus (P < .001). A cell migration assay revealed adequate cell migration rates for MTA Repair HP and NeoMTA Plus, both similar to the control group rates, meanwhile the highest cell migration rate was observed in the presence of Biodentine (P < .001). Scanning electron microscope studies showed a high degree of cell proliferation and adhesion on Biodentine disks but moderate rates on MTA Repair HP and NeoMTA Plus disks. Energy-dispersive X-ray pointed to similar weight percentages of C, O, and Ca in all 3 materials, whereas other elements such as Al, Si, and S were also found.

CONCLUSIONS

The new pulp-capping materials MTA Repair HP, NeoMTA Plus, and Biodentine showed a suitable degree of cytocompatibility with hDPSCs, and good cell migration rates, although Biodentine showed higher rates of proliferation time-dependent.

In Vitro Findings of Titanium Functionalized with Estradiol via Polydopamine Adlayer

To improve orthopedic implant fixation and reduce post-operative complications, osteogenic molecules are delivered locally by immobilizing them on the surface of implants, which will modulate the biology of cell attachment and differentiation on the implant surface. Estradiol, a natural steroid hormone, maintains bone metabolism by decreasing bone resorption. It either directly or indirectly affects osteoclasts. In this work, estradiol was immobilized on a titanium surface by polydopamine adlayer. Immobilization of estradiol was confirmed by X-ray electron spectroscopy (XPS), immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA). Estradiol-modified substrates enhanced alkaline phosphatases activity (ALP) and calcium deposition of osteoblasts. However, these substrates did not decrease tartrate-resistant acid phosphatase (TRAP) activity and actin ring formation of the osteoclast. The scanning electron microscopic (SEM) images of estradiol-modified substrates showed the formation of estradiol crystals, which decreased the potency of immobilized estradiol. Despite having a successful immobilization of estradiol via the polydopamine technique, the bioavailability and potency of coated estradiol is reduced due to crystallization, suggesting that this is not a suitable system for localized estradiol delivery as tested in vitro here. Consequently, other suitable platforms have to be explored for immobilizing estradiol that will prevent crystal formation while preserving the biological activity.

The Role of MicroRNA-143-5p in the Differentiation of Dental Pulp Stem Cells into Odontoblasts by Targeting Runx2 via the OPG/RANKL Signaling Pathway

This study aims to elucidate the mechanisms by which microRNA-143-5p (miR-143-5p) targets runt-related transcription factor 2 (Runx2) in the differentiation of dental pulp stem cells (DPSCs) into odontoblasts, through regulating the osteoprotegerin receptor activator of the nuclear factor-κB ligand (OPG/RANKL) signaling pathway. Following transfection, DPSCs were divided into blank, control, miR-143-5p mimics, miR-143-5p inhibitors, miR-143-5p inhibitors + siRunx2 and siRunx2 groups. Alkaline phosphatase (ALP) activity and mineralized nodules were detected using ALP kit and alizarin red staining. Quantitative reverse transcriptase real time PCR (qRT-PCR) was conducted to measure mRNA expressions of miR-143-5p, Runx2, OPG, and RANKL. Western blotting was used to assess protein expression of odontoblast differentiation-related proteins. Transwell assay and an extracellular matrix (ECM) adhesion cell assay were employed to examine cell migration and cell adhesion. Compared with the blank group, the miR-143-5p mimics and siRunx2 groups showed decreased ALP activity, decreased mineralized nodules and displays of calcium. Fewer migrated cells, weakened cell adhesion, decreased protein expression of dentin phosphoprotein (DPP), dentin sialoprotein (DSP), dentin matrix protein 1 (DMP1), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), OPG and Runx2, and increased RANKL protein expressions were observed. Additionally, opposite results were observed in the miR-143-5p inhibitors group, demonstrating that down-regulated miR-143-5p promotes the differentiation of DPSCs into odontoblasts by enhancing Runx2 expression via the OPG/RANKL signaling pathway. Based on findings in this study, it is postulated that the enhancement of Runx2 expression via the regulation of the OPG/RANKL signaling pathway could be a beneficial approach for dental pulp regeneration. J. Cell. Biochem. 119: 536-546, 2018. © 2017 Wiley Periodicals, Inc.

Physicochemical properties and cytotoxicity of an experimental resin-based pulp capping material containing the quaternary ammonium salt and Portland cement

AIM

To evaluate in vitro the physicochemical properties, cytotoxicity and calcium phosphate nucleation of an experimental light-curable pulp capping material composed of a resin with antibacterial monomer (MAE-DB) and Portland cement (PC).

METHODOLOGY

The experimental material was prepared by mixing PC with a resin containing MAE-DB at a 2 : 1 ratio. Cured pure resin containing MAE-DB served as control resin. ProRoot MTA and Dycal served as commercial controls. The depth of cure, degree of monomer conversion, water absorption and solubility of dry samples, calcium release, alkalinizing activity, calcium phosphate nucleation and the cytotoxicity of materials were evaluated. Statistical analysis was carried out using anova followed by Tukey's HSD test (equal variance assumed) or Tamhane test (equal variance not assumed) and independent-samples t-tests.

RESULTS

The experimental material had a cure depth of 1.19 mm, and the mean degree of monomer conversion was 70.93% immediately post-cure and 88.75% at 24 h post-cure. The water absorption of the experimental material was between those of MTA and Dycal, and its solubility was significantly less (P < 0.05) than that of Dycal and higher than that of MTA. The experimental material exhibited continuous calcium release and an alkalinizing power between those of MTA and Dycal throughout the test period. Freshly set experimental material, control resin and all 24-h set materials had acceptable cytotoxicity. The experimental material, MTA and Dycal all exhibited the formation of apatite precipitates after immersion in phosphate-buffered saline.

CONCLUSIONS

The experimental material possessed adequate physicochemical properties, low cytotoxicity and good calcium phosphate nucleation.