Effects of ProRoot MTA, Bioaggregate, and Micromega MTA on Odontoblastic Differentiation in Human Dental Pulp Cells

Effect of magnesium oxide nanoparticles and LED irradiation on the viability and differentiation of human stem cells of the apical papilla

PURPOSE

Currently, regenerative endodontic treatments are gaining more and more attention, and stem cells play a significant role in these treatments. In order to enhance stem cell proliferation and differentiation, a variety of methods and materials have been used. The purpose of this study was to determine the effects of magnesium oxide nanoparticles and LED irradiation on the survival and differentiation of human stem cells from apical papilla.

METHODS

The MTT test was used to measure the cell survival of SCAPs that had been exposed to different concentrations of magnesium oxide nanoparticles after 24 and 48 h, and the concentration with the highest cell survival rate was picked for further studies. The cells were classified into four distinct groups based on their treatment: (1) control, which received no exposure, (2) exposure to magnesium oxide nanoparticles, (3) exposure to light emitting diode (LED) irradiation (635 nm, 200 mW/cm2) for 30 s, (4) exposure simultaneously with magnesium oxide nanoparticles and LED irradiation. A green approach was employed to synthesize magnesium oxide nanoparticles. Quantitative real time PCR was used to measure the gene expression of osteo/odontogenic markers such as BSP, DSPP, ALP and DMP1 in all four groups after treatment, and Alizarin red S staining (ARS) was used to determine the osteogenic differentiation of SCAPs by demonstrating the Matrix mineralization.

RESULTS

The highest viability of SCAPs was observed after 24 h in concentration 1 and 10 µg/mL and after 48 h in concentration 1 µg/mL, which were not significantly different from the control group. In both times, the survival of SCAPs decreased with increasing concentration of magnesium oxide nanoparticles (MgONPs). According to the results of Real-time PCR, after 24 and 48 h, the highest differentiation of BSP, DMP1, ALP and DSPP genes was observed in the LED + MgONPs group, followed by MgONPs and then LED, and in all 3 experimental groups, it was significantly higher than control group (P < 0.05). Also, after 24 and 48 h, the density of ARS increased in all groups compared to the control group, and the highest density was observed in the MgONPs + LED and MgONPs groups.

CONCLUSION

This research concluded that exposure to SCAPs, MgONPs, and LED irradiation has a significant effect on enhancing gene expression of odontogenic/osteogenic markers and increasing matrix mineralization.

Chemomechanical Properties and Biocompatibility of Various Premixed Putty-type Bioactive Ceramic Cements

INTRODUCTION

This study aimed to evaluate the chemomechanical properties and biocompatibility of recently introduced premixed putty-type bioactive ceramic cements (PPBCs).

METHODS

Including ProRoot MTA (PMTA) as a control, BC RRM fast-set putty (BCPT), Well-Root PT (WRPT), One-Fil PT (OFPT), and Endocem MTA premixed (ECPM) were compared to evaluate setting time, radiopacity, pH change, and microhardness. Biocompatibility on human dental pulp cells was compared using CCK-8 assay. Mineralization potential was evaluated using alkaline phosphatase activity, Alizarin Red S (ARS) staining, and quantitative real-time polymerase chain reaction with odontogenic gene marker. For data analysis, 1-way analysis of variance and Tukey's post hoc test were used at the significance level of 95%.

RESULTS

Among the PPBCs, BCPT presented the longest (552 ± 27) setting time (minutes) and others showed significantly shorter time than PMTA (334 ± 22) (P < .05). WRPT (6.20 ± 0.54) and OFPT (5.82 ± 0.50) showed significantly higher radiopacity values (mmAl) and others showed similar value compared with PMTA (P > .05). All PPBCs showed high alkaline pH from fresh materials and tended to increase according to time periods from 30 minutes to 12 hours. ECPM showed the highest value of microhardness (81.62 ± 5.90), WRPT showed similar, and others showed lower than PMTA (P < .05). All PPBCs showed biocompatibility in CCK-8 assay. All PPBCs showed similar or better value compared with PMTA in ALP and ARS staining, and ALP and DSPP marker expression (P < .05).

CONCLUSIONS

The PPBCs showed clinically acceptable chemomechanical properties and favorable mineralization potential.

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.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Molecular mechanism of a novel root-end filling material containing zirconium oxide on the osteogenic/odontogenic differentiation of human osteosarcoma MG-63 cells

Although the novel root-end filling material containing zirconium oxide (NRFM-Zr) which is hydroxyapatite-based may promote osteoblast differentiation, the molecular mechanism remains unclear. The aim of this study is to investigate it underlying the osteogenic/odontogenic differentiation of human osteosarcoma MG-63 cells induced by NRFM-Zr, compared with calcium silicate-based mineral trioxide aggregate (MTA), and glass ionomer cement (GIC). Firstly, three different types of root filling materials were co-cultured with MG-63 cells, and their cell toxicity, alkaline phosphatase (ALP) activity, and calcium ion concentration were evaluated. Next, gene expression profiling microarray was employed to analyze the impact of the materials on the gene expression profile of MG-63 cells. The results of cell viability revealed that NRFM-Zr group had no significant difference compared to the negative control group. After 5 and 7 days of cultivation, both the NRFM-Zr and MTA groups exhibited significantly higher ALP activity compared to the negative control (p < 0.05). Moreover, the NRFM-Zr group had the highest calcium ion concentration, while the GIC group was the lowest (p < 0.05). Gene expression profiling microarray analysis identified 2915 (NRFM-Zr), 2254 (MTA) and 392 (GIC) differentially expressed genes, respectively. GO functional and KEGG pathway analysis revealed that differentially expressed genes of NRFM-Zr, MTA and GIC participated in 8, 6 and 0 differentiation-related pathways, respectively. Comparing the molecular mechanisms of osteogenic/odontogenic differentiation induced by hydroxyapatite-based NRFM-Zr and calcium silicate-based MTA, it was found that they shared similarities in their molecular mechanisms of promoting osteogenic differentiation. NRFM-Zr primarily promotes differentiation and inhibits cell apoptosis, thereby enhancing osteogenic/odontogenic differentiation of MG-63 cells. Furthermore, the inducing efficacy of NRFM-Zr was found to be superior to MTA.

Role of alpha smooth muscle actin in odontogenic differentiation of dental pulp stem cells

Pulpotomy is an effective treatment for retaining vital pulp after pulp exposure caused by caries removal and/or trauma. The expression of alpha smooth muscle actin (α-SMA) is increased during the wound-healing process, and α-SMA-positive fibroblasts accelerate tissue repair. However, it remains largely unknown whether α-SMA-positive fibroblasts influence pulpal repair. In this study, we established an experimental rat pulpotomy model and found that the expression of α-SMA was increased in dental pulp after pulpotomy relative to that in normal dental pulp. In vitro results showed that the expression of α-SMA was increased during the induction of odontogenic differentiation in dental pulp stem cells (DPSCs) compared with untreated DPSCs. Moreover, α-SMA overexpression promoted the odontogenic differentiation of DPSCs via increasing mitochondrial function. Mechanistically, α-SMA overexpression activated the mammalian target of rapamycin (mTOR) signaling pathway. Inhibition of the mTOR signaling pathway by rapamycin decreased the mitochondrial function in α-SMA-overexpressing DPSCs and suppressed the odontogenic differentiation of DPSCs. Furthermore, we found that α-SMA overexpression increased the secretion of transforming growth factor beta-1 (TGF-β1). In sum, our present study demonstrates a novel mechanism by which α-SMA promotes odontogenic differentiation of DPSCs by increasing mitochondrial respiratory activity via the mTOR signaling pathway.

Assessment of pH Value and Release of Calcium Ions in Calcium Silicate Cements: An In Vitro Comparative Study

The goal of this study was to evaluate the pH and the release of calcium from four calcium-silicate-based cements.

METHODS

Four materials were tested (ProClinic MTA; Angelus MTA; ProRoot MTA; Biodentine). The palatal canal root of acrylic upper molars was filled with each cement. Afterwards, they were set in phosphate-buffered saline. Measurements were taken by atomic adsorption spectroscopy (AAS) at 3, 24, 72, 168, 336, 672, and 1008 h. The pH was measured at the same timepoints. Kruskal-Wallis tests were carried out in each period, as the Kolmogorov-Smirnov and Shapiro-Wilk tests showed no parametric results.

RESULTS

Significant differences (p < 0.05) in calcium release were found at the 3-, 24-, and 72-hour evaluations. All of the analyzed groups presented a release of calcium ions up to 168 h, and the general tendency was to increase up to 672 h, with a maximum release of 25.45 mg/g in the ProRoot group. We could only observe significant differences (p < 0.05) in pH value over 168 h between the Biodentine (7.93) and Angelus MTA (7.31) groups.

CONCLUSIONS

There were significant differences (p < 0.05) in calcium release. Nevertheless, no significant differences (p > 0.05) in the pH values were found at the studied timepoints, except for the values at 168 h.

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.

Analysis of Pulp Tissue Viability and Cytotoxicity of Pulp Capping Agents

The present research study assessed the cell viability and cytotoxic effect of mineral tri-oxide aggregate (MTA), Tetric N-Bond Universal bonding agent, Theracal PT (pulpotomy treatment), and platelet-rich fibrin (PRF) as pulp capping agents on human dental pulp stem cells (hDPSCs). The cells were isolated from the pulp tissue of an extracted healthy permanent third molar. After four passages in Dulbecco’s Modified Eagle’s Medium, the primary cells were employed for the investigation. The test materials and untreated cells (negative control) were subjected to an Methylthiazol-diphenyl-tetrazolium (MTT) cytotoxicity assay and assessed at 24-, 48-, and 72-h intervals. The Wilcoxon matched-paired t-test and Kruskal−Wallis analysis of variance (ANOVA) test were applied (p < 0.05). PRF imparted the highest cell viability at 48 h (p < 0.001), followed by MTA, Theracal PT, and Tetric N-Bond. Similarly, PRF had the highest potential to enhance cell proliferation and differentiation (p < 0.001), followed by Theracal PT, MTA, and the bonding agent at the end of 24 h and 72 h, respectively. Finally, PRF sustained the viability of human primary dental pulp stem cells more effectively than Theracal PT and MTA; however, the application of a Tetric N-Bond as a pulp capping agent was ineffective.

Biomimetic Approaches in Clinical Endodontics

In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area.

Outcome of pulpotomy in permanent teeth with irreversible pulpitis: a systematic review and meta-analysis

Treatment planning is key to clinical success. Permanent teeth diagnosed with "irreversible pulpitis" have long been implied to have an irreversibly damaged dental pulp that is beyond repair and warranting root canal treatment. However, newer clinical approaches such as pulpotomy, a minimally invasive and biologically based procedure have re-emerged to manage teeth with pulpitis. The primary aim of the study was to conduct a meta-analysis to comprehensively estimate the overall success rate of pulpotomy in permanent teeth with irreversible pulpitis as a result of carious pulp exposure. The secondary aim of the study was to investigate the effect of predictors such as symptoms, root apex development (closed versus open), and type of pulp capping material on the success rate of pulpotomy. Articles were searched using PubMed, Scopus, CENTRAL, and Web of Science databases, until January 2021. Outcomes were calculated by pooling the success rates with a random effect model. Comparison between the different subgroups was conducted using the z statistic test for proportion with significance set at alpha = 0.05. A total of 1,116 records were retrieved and 11 studies were included in the quantitative analysis. The pooled success rate for pulpotomy in teeth with irreversible pulpitis was 86% [95% CI: 0.76-0.92; I² = 81.9%]. Additionally, prognostic indicators of success were evaluated. Stratification of teeth based on (1) symptoms demonstrated that teeth with symptomatic and asymptomatic irreversible pulpitis demonstrated success rate of 84% and 91% respectively, with no significant difference (p = 0.18) using z-score analysis; (2) open apex teeth demonstrated a significantly greater success rate (96%) compared to teeth with closed apex (83%) (p = 0.02), and (3) pulp capping materials demonstrated that Biodentine yielded significantly better success rates compared to Mineral Trioxide Aggregate (MTA), calcium hydroxide, and Calcium Enriched Mixture (CEM.) Collectively, this is the first meta-analytical study to determine the clinical outcome of pulpotomy for carious teeth with irreversible pulpitis and it's predictors for success. Moreover, we identify the stage of root development and type of biomaterial as predictors for success of pulpotomy.

Multiple growth factors accommodated degradable submicron calcium sulfate hemihydrate/porous hydroxyapatite for dentin-pulp regeneration

Vital pulp therapy (VPT) has gained significant consideration by utilizing the natural healing capacity of the inflamed pulp in healing process. However, the protective pulp capping materials that facilitate this healing process are still under investigation for the successful promotion of dentin-pulp regeneration. Herein, we developed a bioactive and biodegradable pulp capping material (denoted as sCSHA-GFs) by synthesizing inorganic submicron calcium sulfate hemihydrate (sCS)/porous hydroxyapatite (HA) loaded with growth factors (GFs) such as transforming growth factor-beta 1 (TGF-β1), fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF). Physiochemical characteristics of submicron CSHA-GFs (sCSHA-GFs) cement were determined. Human dental pulp stem cells (hDPSCs) were used for analyzing their biocompatibility and bioactivity for dentin mineralization. To evaluate the efficacy of sCSHA-GFs, we compared it with a commercial material, mineral trioxide aggregate (MTA), the reference standard used clinically on pulp capping. Our results showed that sCSHA-GFs cement presented good biodegradability with dissolution properties for sustained release of calcium (Ca²⁺) ions and GFs, and facilitated attachment, proliferation, differentiation and migration of hDPSCs. In addition, sCSHA-GFs cement was found to be more effective than MTA at prolonged incubation time in inducing the mRNA expression levels of odontoblastic differentiation markers, dentin sialophosphoprotein (DSPP) and dentin matrix protein (DMP-1), leading to increased mineralization (with calcium deposits) along with increased alkaline phosphatase (ALP) expressions, evident from Alizarin Red S and ALP staining assays. Our findings suggest that sCSHA-GFs cement may act as a suitable material in VPT for dentin-pulp regeneration.

Pulpal expression of erythropoietin and erythropoietin receptor after direct pulp capping in rat

This study aimed to evaluate the effect of direct pulp capping on the expression of erythropoietin (Epo) and Epo-receptor (Epor) genes in relation to the expression of inflammatory and osteogenic genes in rat pulp. Dental pulps of the first maxillary molars of Wistar Albino rats were exposed and capped with either calcium hydroxide or mineral trioxide aggregate, or were left untreated. After 4 wk, animals were euthanized, and maxillae were prepared for histological and real-time polymerase chain reaction analysis. Histological scores of pulp inflammation and mineralization, and relative expressions of Epo, Epor, inflammatory cytokines, and pulp osteogenic genes were evaluated. The capped pulps showed higher expressions of Epo, while the untreated pulps had the highest expression of Epor. Both calcium hydroxide and mineral trioxide aggregate downregulated the expression of tumor necrosis factor alpha compared to untreated controls, and upregulated transforming growth factor beta compared to healthy controls. Alkaline phosphatase expression was significantly higher in experimental groups. Relative expression of Epo negatively correlated with pulp inflammation, and positively correlated with pulp mineralization. Pulp exposure promoted expression of Epor and pro-inflammatory cytokines, while pulp capping promoted expression of Epo, alkaline phosphatase, and downregulated Epor and pro-inflammatory cytokines.

Physicochemical and biological properties of four calcium silicate-based endodontic cements

Background/purpose

Materials and methods

Results

Conclusion

The additive effect of iloprost on the biological properties of Mineral trioxide aggregate on mesenchymal stem cells

Background/purpose

Iloprost has been proposed as a potential biomaterial owing to angiogenic and odontogenic properties. However, the liquid form can limit its use during clinical applications. Mineral trioxide aggregate (MTA) has been used for various dental applications in which cell–material interaction is essential. This study aimed to investigate additive effects of iloprost on the biological properties of MTA on the viability, attachment, migration and differentiation of human mesenchymal stem cells (hMSCs).

Materials and methods

Standardized human dentin disks were prepared. MTA was prepared by mixing distilled water or iloprost solution, and the lumen of the disks was filled with MTA or MTA-iloprost. hMSCs on disk alone and hMSCs on culture plates were used as controls. Cell viability and attachment were measured after 1, 7 and 14 days using AlamarBlue assay and scanning electron microscopy (SEM). Cell migration in MTA or MTA-iloprost extracts was determined using a wound-healing model.

Osteogenic differentiation was evaluated by real-time reverse transcriptase polymerase chain reaction for alkaline phosphatase (ALP), bone sialoprotein (BSP), osteocalcin (OCN), and osteopontin (OSP) gene expressions after 7 and 14 days of osteogenic induction.

Results

Cells on MTA-iloprost surface showed similar viability with MTA at 1 and 14 days but enhanced cellular viability and cell spreading compared to MTA at 7 days (p < 0.05). Cell migration was similar by MTA-iloprost and MTA extracts (p > 0.05). MTAiloprost significantly upregulated BSP, OCN and OSP expressions compared to MTA (p < 0.05).

Conclusion

The addition of iloprost to MTA improved the initial cell viability and osteogenic potential of hMSCs.

Evaluation of a collagen-bioaggregate composite scaffold in the repair of sheep pulp tissue

Purpose:

This study aimed to compare the effects of the collagen-BioAggregate mixture (CBA-M) and collagen-BioAggregate composite (CBA-C) sponge as a scaffolding material on the reparative dentin formation.

Materials and methods:

CBA-C sponge (10:1 w/w) was obtained and characterized by Scanning Electron Microscopy (SEM) and Mercury Porosimetry. Cytotoxicity of the CBA-C sponge was tested by using the L929 mouse fibroblast cell line. Dental pulp stem cells (DPSCs) were isolated from the pulp tissue of sheep teeth and characterized by flow cytometry for the presence of mesenchymal stem cell marker, CD44. The osteogenic differentiation capability of isolated DPSCs was studied by Alizarin Red staining. The cells were then used to study for the compatibility of CBA-C sponge with cell proliferation and calcium phosphate deposition. The effect of CBA-C sponge and CBA-M on the induction of dentin regeneration was studied in the perforated teeth of sheep for the eight-week period. All the analyses were performed with appropriate statistical hypothesis tests.

Results:

CBA-C sponge was found to be biocompatible for DPSCs. The DPSCs seeded on the CBA-C sponge were able to differentiate into the osteoblastic lineage and deposit calcium phosphate crystals in vitro. Reparative dentin formation was observed after the second week in the CBA-C sponge applied group. At the end of eight weeks, a complete reparative dentin structure was formed in the CBA-C sponge applied group, whereas necrotic tissue residues were observed in groups treated with the CBA-M.

Conclusion:

CBA-C sponge represents a better microenvironment for reparative dentin formation probably due to maintaining DPSCs and allowing their osteogenic differentiation and thus calcium phosphate deposition.

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

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

Human dental pulp stem cell responses to different dental pulp capping materials

Background

Direct pulp capping is a vital pulp therapy for a pin-point dental pulp exposure. Applying a pulp capping material leads to the formation of a dentin bridge and protects pulp vitality. The aim of this study was to compare the effects of four dental materials, DyCal^®, ProRoot^® MTA, Biodentine™, and TheraCal™ LC in vitro.

Methods

Human dental pulp stem cells (hDPs) were isolated and characterized. Extraction medium was prepared from the different pulp capping materials. The hDP cytotoxicity, proliferation, and migration were examined. The odonto/osteogenic differentiation was determined by alkaline phosphatase, Von Kossa, and alizarin red s staining. Osteogenic marker gene expression was evaluated using real-time polymerase chain reaction.

Results

ProRoot^® MTA and Biodentine™ generated less cytotoxicity than DyCal^® and TheraCal™ LC, which were highly toxic. The hDPs proliferated when cultured with the ProRoot^® MTA and Biodentine™ extraction media. The ProRoot^® MTA and Biodentine™ extraction medium induced greater cell attachment and spreading. Moreover, the hDPs cultured in the ProRoot^® MTA or Biodentine™ extraction medium migrated in a similar manner to those in serum-free medium, while a marked reduction in cell migration was observed in the cells cultured in DyCal^® and TheraCal™ LC extraction media. Improved mineralization was detected in hDPs maintained in ProRoot^® MTA or Biodentine™ extraction medium compared with those in serum-free medium.

Conclusion

This study demonstrates the favorable in vitro biocompatibility and bioactive properties of ProRoot^® MTA and Biodentine™ on hDPs, suggesting their superior regenerative potential compared with DyCal^® and TheraCal™.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01544-w.

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.

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.

Preclinical effectiveness of an experimental tricalcium silicate cement on pulpal repair

OBJECTIVES

To investigate the pulpal repair potential of an experimental zirconium-oxide containing tricalcium-silicate cement, referred to as 'TCS 50'.

MATERIALS AND METHODS

The effect of TCS 50 on viability, proliferation, migration, and odontoblastic differentiation of human dental pulp cells (HDPCs) was assessed using XTT assay, in-vitro wound healing assay and RT-PCR, respectively. Additionally, the pulp-capping potential was evaluated using a vital human tooth model. Statistical analysis was performed using non-parametric Kruskal-Wallis test and post-hoc test (Mann-Whitney U test). The tests were performed at a significance level of α = 0.05.

RESULTS

The effect of TCS 50 towards HDPCs was dose dependent. Undiluted TCS 50 extract showed no immediate adverse impact on cell viability (p > .05); however, it significantly inhibited proliferation and migration of HDPCs (p < .05). A 25% diluted TCS 50 extract showed no significant effect on cell viability, proliferation or migration (p > .05), and it significantly enhanced odontoblastic differentiation of HDPCs (p < .05). In pulps capped with TCS 50 for both 2 and 4 weeks, H&E staining revealed a normal morphology of pulp tissue; mineralized foci with cellular components entrapped in the matrix were formed underneath the exposure site. Collagen I expression was weak within the matrix of mineralized foci, while the expression of nestin was positive for entrapped cellular components within the mineralized foci, indicating that the formed mineralized foci corresponded to an initial form of reparative dentin formation.

CONCLUSION

TCS 50 is capable of generating an early pulp-healing reaction and therefore could serve as a promising pulp-capping agent.

Evaluation of dentinogenesis inducer biomaterials: an in vivo study

When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of ^99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot^®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

Induction of Osteogenic Differentiation of Mesenchymal Stem Cells by Bioceramic Root Repair Material

This study aimed to evaluate the osteogenic activity of Endosequence Root Repair Material (ERRM) putty using rat mesenchymal stem cells (MSCs). The extract of set ERRM and ProRoot-mineral trioxide aggregate (MTA) (control) was cocultured with rat MSCs and incubated for one, three, and seven days. The cell viability and proliferation were assessed. A quantitative real-time polymerase chain reaction for bone morphogenetic protein-2 (BMP-2), alkaline phosphatase, bone sialoprotein, and osteocalcin gene expression was performed. Both materials enhanced cell viability and proliferation, which increased over time. On day seven, the cells treated with either material exhibited significantly greater cell viability compared with control untreated cells. MSCs treated with either material showed deeper alkaline phosphatase staining after three days compared to control untreated cells. Treated MSCs also exhibited upregulation of the gene expression of bone morphogenetic protein-2, alkaline phosphatase, bone sialoprotein, and osteocalcin. Both ERRM and ProRoot-MTA enhance the osteogenic differentiation of MSCs.

Expression and influence of BMP-4 in human dental pulp cells cultured in vitro

Effects of bone morphogenetic protein (BMP)-4 on proliferation and differentiation capacities of dental pulp cells through BMP-4 acting on human dental pulp cells cultured in vitro were investigated. Dental pulp tissues of lesion-free teeth extracted from patients due to orthodontics were taken, and human dental pulp cells were cultured in vitro using the tissue explant method. Immunocytochemical staining was used for the identification of vimentin and keratin. The dental pulp cells were divided into groups A and B. A total of 100 ng/ml BMP-4 was added into group A, while no inducer was added into group B as the control group. The cell growth curves at day 1, 2, 3, 5 and 7 after culture were drawn. At day 7, the cell count, alkaline phosphatase (ALP) activity, number of calcified nodules, and expression levels of dentin sialophosphoprotein (DSPP), dentin matrix protein-1 (DMP-1) and each gene related to dentinogenesis in each group were detected, respectively. Human dental pulp cells were conformed to the biological characteristics of dental pulp cells according to the identification of vimentin and keratin via immunocytochemical staining. With the prolongation of culture time, the number of cells in both groups was gradually increased, reaching the peak at day 5 and began to decline at day 7. The number of cells in group A was significantly greater than that in group B (p<0.05). According to the results of reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the relative messenger ribonucleic acid (mRNA) expression levels of ALP, DSPP and DMP-1 in group A were significantly higher than those in group B (p<0.05). BMP-4 can promote the growth of dental pulp cells and remarkably enhance the differentiation of dental pulp cells into odontoblasts.

Effects of four novel root-end filling materials on the viability of periodontal ligament fibroblasts

Objectives

The aim of this in vitro study was to evaluate the biocompatibility of newly proposed root-end filling materials, Biodentine, Micro-Mega mineral trioxide aggregate (MM-MTA), polymethylmethacrylate (PMMA) bone cement, and Smart Dentin Replacement (SDR), in comparison with contemporary root-end filling materials, intermediate restorative material (IRM), Dyract compomer, ProRoot MTA (PMTA), and Vitrebond, using human periodontal ligament (hPDL) fibroblasts.

Materials and Methods

Ten discs from each material were fabricated in sterile Teflon molds and 24-hour eluates were obtained from each root-end filling material in cell culture media after 1- or 3-day setting. hPDL fibroblasts were plated at a density of 5 × 10³/well, and were incubated for 24 hours with 1:1, 1:2, 1:4, and 1:8 dilutions of eluates. Cell viability was evaluated by XTT assay. Data was statistically analysed. Apoptotic/necrotic activity of PDL cells exposed to material eluates was established by flow cytometry.

Results

The Vitrebond and IRM were significantly more cytotoxic than the other root-end filling materials (p < 0.05). Those cells exposed to the Biodentine and Dyract compomer eluates showed the highest survival rates (p < 0.05), while the PMTA, MM-MTA, SDR, and PMMA groups exhibited similar cell viabilities. Three-day samples were more cytotoxic than 1-day samples (p < 0.05). Eluates from the cements at 1:1 dilution were significantly more cytotoxic (p < 0.05). Vitrebond induced cell necrosis as indicated by flow cytometry.

Conclusions

This in vitro study demonstrated that Biodentine and Compomer were more biocompatible than the other root-end filling materials. Vitrebond eluate caused necrotic cell death.

Chemical Composition and Porosity Characteristics of Various Calcium Silicate-Based Endodontic Cements

Chemical composition and porosity characteristics of calcium silicate-based endodontic cements are important determinants of their clinical performance. Therefore, the aim of this study was to investigate the chemical composition and porosity characteristics of various calcium silicate-based endodontic cements: MTA-angelus, Bioaggregate, Biodentine, Micromega MTA, Ortho MTA, and ProRoot MTA. The specific surface area, pore volume, and pore diameter were measured by the porosimetry analysis of N2 adsorption/desorption isotherms. Chemical composition and powder analysis by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were also carried out on these endodontic cements. Biodentine and MTA-angelus showed the smallest pore volume and pore diameter, respectively. Specific surface area was the largest in MTA-angelus. SEM and EDS analysis showed that Bioaggregate and Biodentine contained homogenous, round and small particles, which did not contain bismuth oxide.

EZH2 Impairs Human Dental Pulp Cell Mineralization via the Wnt/β-Catenin Pathway

The enhancer of zeste homolog 2 (EZH2) is a catalytic subunit of PRC2 (polycomb repressor complex 2). It mediates gene silencing via methyltransferase activity and is involved in the determination of cell lineage. However, the function of EZH2 and the underlying mechanisms by which it affects the differentiation of human dental pulp cell (hDPC) have remained underexplored. In this research, we found that EZH2 expression decreased during the mineralization of hDPCs, with attenuated H3K27me3 (trimethylation on lysine 27 in histone H3). Overexpression of EZH2 impaired the odontogenic differentiation of hDPCs, while EZH2 without methyltransferase activity mutation (mutation of suppressed variegation of 3 to 9, enhancer of zeste and trithorax domain, EZH2ΔSET) did not display this phenotype. In addition, siRNA knockdown studies showed that EZH2 negatively modulated hDPC differentiation in vitro and inhibited mineralized nodule formation in transplanted β-tricalcium phosphate / hDPC composites. To further investigate the underlying mechanisms, we explored the Wnt/β-catenin signaling pathway in view of the fact that previous research had documented the essential role that it plays during hDPC mineralization, as well as its links to EZH2 in other cells. We demonstrated for the first time that EZH2 depletion activated the Wnt/β-catenin signaling pathway and enhanced the accumulation of β-catenin in hDPCs. Chromatin immunoprecipitation analysis suggested that these effects are attributable to the level of the EZH2-regulated H3K27me3 on the β-catenin promoter. We conclude that EZH2 plays a negative role during the odontogenic differentiation of hDPCs. Suppression of EZH2 could promote hDPC mineralization by epigenetically regulating the expression of β-catenin and activating the Wnt canonical signaling pathway.

Ion Release, Microstructural, and Biological Properties of iRoot BP Plus and ProRoot MTA Exposed to an Acidic Environment

INTRODUCTION

This study evaluated how exposing the novel calcium silicate nanoparticulate bioceramic iRoot BP Plus (Innovative Bioceramix, Vancouver, Canada) to an acidic environment affects ion release from this material and alters MC3T3-E1 preosteoblast viability on and attachment to this material. These factors were compared against those of ProRoot MTA under similar conditions.

METHODS

Each material was exposed to phosphate-buffered saline (pH = 7.4) or butyric acid (pH = 5.4) for 5 days. Trace metal elements within the 2 materials and released ions were identified using inductively coupled plasma optical emission spectroscopy. The microstructures and elemental compositions of MTA and iRoot BP Plus after treatment with butyric acid were determined using scanning electron microscopy with an energy-dispersive X-ray spectrometer. Furthermore, the viability of MC3T3-E1 cells on and their levels of attachment to the materials after the butyric acid treatment were compared.

RESULTS

iRoot BP Plus contained fewer toxic metal elements than MTA. Under acidic conditions, both materials displayed similar ion release abilities, with increased release of Si and Ca ions. Substantial changes in microstructure, including reduced apatite formation, were observed for both materials after exposure to acidic pH. Furthermore, exposing iRoot BP Plus and MTA to an acidic environment increased and decreased MC3T3-E1 cell viability on these materials, respectively. MC3T3-E1 cell attachment to both materials was not significantly affected by acidic pH.

CONCLUSIONS

iRoot BP Plus seems more biologically appropriate for application in an inflamed acidic environment than ProRoot MTA.

Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus.

Combined effects of mineral trioxide aggregate and human placental extract on rat pulp tissue and growth, differentiation and angiogenesis in human dental pulp cells

OBJECTIVE

The aim of this study was to evaluate the combined effects of mineral trioxide aggregate (MTA) and human placental extract (HPE) on cell growth, differentiation and in vitro angiogenesis of human dental pulp cells (HDPCs) and to identify underlying signal transduction mechanisms. In vivo dental pulp responses in rats for a pulp-capping agent were examined.

MATERIALS AND METHODS

MTS assay. ALP activity test, alizarin red S staining and RT-PCR for marker genes were carried out to evaluate cell growth and differentiation. HUVEC migration, mRNA expression and capillary tube formation were measured to evaluate angiogenesis. Signal transduction was analysed using Western blotting and confocal microscopy. The pulps of rat maxillary first molars were exposed and capped with either MTA or MTA plus HPE. Histologic observation and scoring were performed.

RESULTS

Compared to treatment of HDPCs with either HPE or MTA alone, the combination of HPE and MTA increased cell growth, ALP activity, mineralized nodules and expression of marker mRNAs. Combination HPE and MTA increased migration, capillary tube formation and angiogenic gene expression compared with MTA alone. Activation of Akt, mammalian target of rapamycin (mTOR), p38, JNK and ERK MAPK, Akt, and NF-κB were significantly increased by combining HPE and MTA compared with MTA alone. Pulp capping with MTA plus HPE in rats showed superior dentin bridge formation, odontoblastic layers and dentinal tubules and lower inflammatory cell response, compared to the MTA alone group.

CONCLUSIONS

This study demonstrates for the first time that the use of MTA with HPE promotes cell growth, differentiation and angiogenesis in HDPCs, which were associated with mTOR, MAPK and NF-κB pathways. Direct pulp capping with HPE plus MTA showed superior results when compared with MTA alone. Thus, the combination of MTA and HPE may be useful for regenerative endodontics.

Cytotoxicity of Various Endodontic Materials on Stem Cells of Human Apical Papilla

INTRODUCTION

This in vitro study assessed and compared the cytotoxicity of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on stem cells of the human apical papilla (SCAP).

METHODS AND MATERIALS

SCAPs were isolated from two semi-impacted third molars. The cells were cultured in wells of an insert 24-well plate and were then incubated. The plates were then removed from the incubator and randomly divided into four experimental groups that were exposed to 1-mm discs of set MTA, CEM, BD or OCP, and one untreated control group. After 24, 48 and 168 h, the plates were removed from the incubator and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) solution was added to each well. Data were analyzed at different time points using the repeated measures ANOVA followed by Bonferroni test and the level of significance was set at 0.05.

RESULTS

Cytotoxicity of the four materials was not significantly different from that of the control group at 24, 48 and 168 h (P>0.05). Two-by-two comparison revealed that cytotoxicity of MTA and CEM cement was significantly different from each other at 168 h (P<0.05) although the cytotoxicity of CEM was less than MTA. Cytotoxicity of OCP and MTA was also significantly different from each other at 48 h and OCP had more favorable biocompatibility than MTA (P<0.05).

CONCLUSION

CEM, OCP, BD and MTA showed acceptable biocompatibility when exposed to SCAP. Over time, CEM showed the least cytotoxicity among the materials under study.

Mitogen-activated protein kinases pathways mediate the sunitinib-induced hypertrophy in rat cardiomyocyte H9c2 cells

Sunitinib (SUN) is a multi-targeted tyrosine kinase inhibitor used for the treatment of gastrointestinal stromal tumors and renal cell carcinoma. Cardiotoxicity has been reported as a significant side effect associated with the SUN treatment, yet the mechanism is poorly understood. The main purpose of this study was to investigate the potential effects of SUN on cardiac hypertrophic genes and the role of mitogen-activated protein kinases (MAPKs) signaling pathway in rat cardiomyocyte H9c2 cell line. In the present study, real-time quantitative polymerase chain reaction showed that the treatment of H9c2 cells with increasing concentrations of SUN (0, 1, 2.5, and 5 µM) significantly induced hypertrophic gene markers, such as brain natriuretic peptides (BNP) and myosin heavy chain (β-MHC and α-MHC) in concentration- and time-dependent manners. The onset of mRNA induction was observed as early as 9 h and remained elevated for at least 18 h after treatment with SUN 5 µM. At the protein level, Western blot analysis showed that SUN increased BNP and β-MHC, while it inhibited α-MHC protein levels in a concentration-dependent manner. These SUN-mediated effects were associated with increase in cell size and hypertrophy by approximately 70 % at the highest concentration, 5 µM. Importantly, inhibition of the MAPK signaling pathway using SB203580 (p38 MAPK inhibitor), U0126 (extracellular signal-regulated kinase inhibitor), and SP600125 (c-Jun NH2-terminal kinase inhibitor) significantly potentiated the SUN-induced BNP and β-MHC mRNA levels, but did alter the α-MHC level. Whereas at the protein level, MAPK inhibitors generally decreased the SUN-induced BNP, whereas only SB and U0 increased β-MHC protein levels with no effect on α-MHC, which were associated with a significant decrease in cell size. Together, these results indicate that SUN induced hypertrophic gene expression through MAPK-dependent mechanisms.

Calcium silicate-based cements: composition, properties, and clinical applications

Mineral trioxide aggregate (MTA) is a calcium silicate-based cement (CSC) commonly used in endodontic procedures involving pulpal regeneration and hard tissue repair, such as pulp capping, pulpotomy, apexogenesis, apexification, perforation repair, and root-end filling. Despite the superior laboratory and clinical performance of MTA in comparison with previous endodontic repair cements, such as Ca(OH)₂ , MTA has poor handling properties and a long setting time. New CSC have been commercially launched and marketed to overcome the limitations of MTA. The aim of the present review was to explore the available literature on new CSC products, and to give evidence-based recommendations for the clinical use of these materials. Within the limitations of the available data in the literature regarding the properties and performance of the new CSC, the newer products could be promising alternatives to MTA; however, further research is required to support this assumption.

The Effects of Endosequence Root Repair Material on Differentiation of Dental Pulp Cells

INTRODUCTION

Pulp capping techniques aim at preserving the vitality of pulp tissue, thus avoiding more invasive endodontic procedures. Endosequence Root Repair Material (ERRM; Brasseler USA, Savannah, GA) has been recently introduced as a potential pulp capping material. It is hypothesized that ERRM promotes the healing of dental tissue, thus maintaining the integrity and vitality of the pulp after pulp capping procedures. However, the exact mechanism by which ERRM affects the pulp after pulp capping procedures is still unknown. Therefore, the aim of this research was to delineate the effects of ERRM on the dental pulp and compare these effects to those of ProRoot MTA.

METHODS

The effects of ERRM on dental pulp cells (DPCs) were compared with ProRoot mineral trioxide aggregate (MTA) (Tulsa Dental, Tulsa, OK). The effects of the 2 materials on the cells were analyzed using various assays such as flow cytometric analysis using FITC Annexin V and PI (BD Biosciences, Franklin Lakes, NJ), WST-1 proliferation assay (Millipore, Billerica, MA), vascular endothelial growth factor (VEGF) enzyme-linked immunosorbent assay, and an alkaline phosphatase (ALP) assay. Results were analyzed using analysis of variance with a post hoc Tukey test and the level of significance set at P ≤ .05.

RESULTS

The results showed that DPCs had similar percentages of viable cells when grown on either material. Furthermore, the proliferation rates, secretion of VEGF, and levels of ALP were similar for DPCs when cultured on either ERRM or ProRoot MTA.

CONCLUSIONS

Overall, this study showed similar survival and proliferation of DPCs when in contact with ERRM or ProRoot MTA, which could make it a suitable alternative for pulp capping procedures.

Apical Extrusion of Debris after Canal Preparation with Hand-Files Used Manually or Installed on Reciprocating Air-Driven Handpiece in Straight and Curved Canals

Introduction:

Apical debris extrusion (DE) subsequent to root canal instrumentation, is one of the most important causes of endodontic flare-ups. The aim of this study was to compare the amount of DE after root canal instrumentation using nickel-titanium (NiTi) hand files with step-back manual technique or installed on reciprocating handpiece.

Methods and Materials:

This study was conducted on mesiobuccal (MB) roots of extracted maxillary first molars (n=20) and roots of mandibular premolars (n=20) that were randomly divided into two groups (n=20) according to the armamentarium used for canal preparation (air-driven reciprocating handpiece or hand instrumentation). In each group, the MB and premolar roots were prepared with the main apical sizes of 35 and 40, respectively. The extruded debris were collected and weighed. Finally, the mean dry weights were compared using ANOVA and t-test, and Tukey’s Multiple Comparisons Procedures were used to determine the significant differences in amounts of DE. The level of significance was set at 0.05.

Results:

Regardless of the type of teeth, the mean values of DE, were significantly lower in the handpiece group (P<0.0001). In addition, significantly lower amounts of DE was observed in premolars in similar group (P<0.001). However, this difference was not significant in MB roots of molars (P=0.20).

Conclusion:

Root canal preparation with reciprocating handpiece can lead to significantly lower debris extrusion than the manual step-back technique. In handpiece-prepared canals, the amount of extruded debris was significantly lower in premolar teeth.

Human Dental Pulp Cells Responses to Apatite Precipitation from Dicalcium Silicates

Unraveling the mechanisms behind the processes of cell attachment and the enhanced proliferation that occurs as a response to the presence of calcium silicate-based materials needs to be better understood so as to expand the applications of silicate-based materials. Ions in the environment may influence apatite precipitation and affect silicate ion release from silicate-based materials. Thus, the involvement of apatite precipitate in the regulation of cell behavior of human dental pulp cells (hDPCs) is also investigated in the present study, along with an investigation of the specific role of cell morphology and osteocalcin protein expression cultured on calcium silicate (CS) with different Dulbecco's modified Eagle's medium (DMEM). The microstructure and component of CS cement immersion in DMEM and P-free DMEM are analyzed. In addition, when hDPCs are cultured on CS with two DMEMs, we evaluate fibronectin (FN) and collagen type I (COL) secretion during the cell attachment stage. The facilitation of cell adhesion on CS has been confirmed and observed both by scanning with an electron microscope and using immunofluorescence imaging. The results indicate that CS is completely covered by an apatite layer with tiny spherical shapes on the surface in the DMEM, but not in the P-free DMEM. Compared to the P-free DMEM, the lower Ca ion in the DMEM may be attributed to the formation of the apatite on the surfaces of specimens as a result of consumption of the Ca ion from the DMEM. Similarly, the lower Si ion in the CS-soaked DMEM is attributed to the shielding effect of the apatite layer. The P-free DMEM group releases more Si ion increased COL and FN secretion, which promotes cell attachment more effectively than DMEM. This study provides new and important clues regarding the major effects of Si-induced cell behavior as well as the precipitated apatite-inhibited hDPC behavior on these materials.

Initial transient accumulation of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate in rat molars

INTRODUCTION

M2 (alternatively activated) macrophages are known to participate in wound healing and tissue repair. This study aimed to analyze the temporospatial changes in the distribution and density of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate (MTA) in rat molars to ascertain the role played by M2 macrophages in the healing of MTA-capped pulp tissue.

METHODS

The maxillary first molars of 8-week-old Wistar rats were pulpotomized and capped with MTA. After 1-14 days, the teeth were examined after hematoxylin-eosin staining or immunoperoxidase staining of CD68 (a general macrophage marker) and M2 macrophage markers (CD163 and CD204). The density of positively stained cells was enumerated in the surface and inner regions (0-100 μm and 300-400 μm, respectively, from the wound surface).

RESULTS

MTA capping initially caused mild inflammatory changes and the formation of a degenerative layer followed by progressive new matrix formation and calcified bridging. At 1-2 days, CD68-, CD163-, and CD204-positive cells started to accumulate beneath the degenerative layer, and the density of these cells was significantly higher in the surface region than in the inner region (P < .05). From 7 days onward, the 3 types of cells displayed an almost normal distribution beneath the newly formed dentinlike matrix.

CONCLUSIONS

After the pulpotomy of rat molars with MTA, M2 macrophage-associated molecule-expressing cells transiently accumulated beneath the degenerative layer under the MTA. This suggests that M2 macrophages participate in the initial phases of the healing of MTA-capped pulp tissue.