Effects of Mineral Trioxide Aggregate on Cell Survival, Gene Expression Associated with Mineralized Tissues, and Biomineralization of Cementoblasts

Synergistic Effect of Polyethylene Glycol and Lactic Acid on Handling Properties and Antibacterial Efficacy of Premixed Calcium Silicate Cement

Calcium silicate (CaSi) bone cement with antibacterial and osteogenic properties has attracted significant interest. However, there is a need to develop a variety of new premixed bone cement to meet the clinical requirements of fast setting time, ease of handling, and efficient antibacterial properties. In this study, different volume ratios of polyethylene glycol (PEG) and lactic acid liquids were added to calcium silicate, and the effects of varying liquid-to-powder ratios (L/P) were examined. This study assessed the physicochemical properties, cytotoxicity, and antibacterial activity against S. aureus and E. coli of this premixed cement. The results from the experiments indicated that lactic acid significantly reduced the setting time of the CaSi-based cement and enhanced its mechanical strength. Furthermore, the appropriate concentration of lactic acid and matching L/P ratio improved its washout resistance. The cell viability of all premixed cement was found to be over 80%. The premixed cement containing PEG and lactic acid exhibited superior antibacterial properties compared to the CaSi control. Based on its setting time, washout resistance, and antibacterial activity, a premixed cement with a liquid phase of 80% PEG and 20% lactic acid at an L/P ratio of 0.4 appeared promising for use in dental and orthopedic practice.

An Evaluation of the Fracture Resistance of Teeth with Simulated External Cervical Resorption Cavities Categorized Using Three-Dimensional Classification

(1) Background: External cervical resorption causes dental hard tissue destruction that may reduce the fracture resistance of affected teeth. By using a compressive strength test, this study aimed to evaluate the fracture resistance of teeth with simulated external cervical resorption cavities that have different three-dimensional classifications. (2) Methods: In total, 170 teeth with simulated external cervical resorptions were divided into 16 experimental groups (n = 10) and 1 control group (n = 10) based on the three-dimensional classification: 1Ap, 1Bp, 1Cp, 1Dp, 2Ap, 2Bp, 2Cp, 2Dp, 3Ap, 3Bp, 3Cp, 3Dp, 4Ap, 4Bp, 4Cp, 4Dp and a control group. Defects were restored with mineral trioxide aggregate. The fracture resistances of the samples were statistically analyzed using two-way repeated ANOVA and the Bonferroni correction for multiple comparisons at a significance level of p < 0.05. (3) Results: The lowest resistance to fracture was observed in samples with vertical height level "4" and circumferential spread of "D" (p < 0.001). In the groups with circumferential spreads "B", "C" and "D", there were significant differences between the samples with vertical height levels "1", "2", "3" and "4" regarding fracture resistance (p < 0.001). (4) Conclusions: The circumferential spread and vertical height of the external cervical resorption influenced the fracture resistance of the affected teeth.

Analysis of the cytotoxicity and bioactivity of CeraSeal, BioRoot™ and AH Plus® sealers in pre-osteoblast lineage cells

BACKGROUND

The objective of the present study was to evaluate in vitro the cytotoxicity and bioactivity of various endodontic sealers (CeraSeal, BioRoot™ and AH Plus®) in pre-osteoblast mouse cells (MC3T3 cells).

METHODS

MC3T3 cells (ATCC CRL-2594) were plated in 1 × 104 cells/well in 96-well plates in contact with endodontic sealers at concentrations of 1:10 and 1:100. Cell viability was evaluated by MTT assay after 24 and 48 h. In addition, sealer bioactivity was measured by RT-PCR for mediator of inflammation (Tnf, Ptgs2) and mineralization (Runx2, Msx1, Ssp1 and Dmp1) after 24 h and by Alizarin Red S Assay of mineralization after 28 days. Data were analyzed using one-way ANOVA followed by the Tukey's post-test at a significance level of 5%.

RESULTS

BioRoot™ presented 24-hour cytotoxicity (p < 0.05) at 1:10 concentration. In the period of 48 h, no endodontic cement was cytotoxic to the cells compared to the control (p > 0.05). TNF-α gene expression was induced by AH Plus® (p < 0.05), while Ptgs2 was induced by the CeraSeal and BioRoot™ (p < 0.05). The expression of Runx2 was stimulated by BioRoot™ and AH Plus® (p < 0.05). In contrast, the expression of Dmp-1 Dmp1 was higher for the CeraSeal and BioRoot™ (p < 0.05). Nonetheless, the sealers did not impact the formation of mineralization nodules (p > 0.05).

CONCLUSION

CeraSeal, BioRoot™ and AH Plus® sealers were not cytotoxic to MC3T3 cells within 48 h, but differentially induced the expression of genes related to inflammation and mineralization without impacting biomineralization by the cells.

[The use of mineral trioxide aggregate for treatment of children with complications of dental trauma]

THE AIM

Jf the study was to assess the efficacy of mineral trioxide aggregate for treatment of children with complicated permanent teeth trauma.

MATERIAL AND METHODS

The study comprised 29 children aged 6-13 years (mean age 8.6±1.7 years) with 36 injured constant teeth, from which 30 had immature roots, 27 (75%) teeth had necrotic pulp at baseline examination, 12 (33.3%) teeth showed radiological signs of external imflammatory root resorbtion, 2 teeth were diagnosed with of the root fracture (5.6%). MTA was used for pulp regeneration procedure in 25 (69.5%) teeth, external closure of resorbtion site in 3 (8.3%) teeth, root canal filling in 4 (11.1%) teeth, apical plug creation in 4 teeth (11.1%). The patients were folowed up for 1 to 9 years.

RESULTS

From 36 teeth only one was extracted 9 years after regenerative endodontic procedure because of cervical root fracture. In 2 teeth with external imflammatory resorbtion progession of replacement resorption took place, in 1 tooth necrosis of regenerated pulp tissue occurred 2 years after the procedure because of restoration marginal seal failure. In 25 teeth favorable outcome was registered with stabilisation of external root resorbtion, continous root growth in 24 teeth and radioluscent lesions healing in 6 teeht showing them at baseline examination. Change of external imflammator root resorbtion to replacement resorption was detected in 1 teeth from 3 with external closure of resorbtion site. Root calan filling with MTA was performed in 3 avulsed teeth with replantation delayed for more than 1 day and in 1 tooth with root fracture. All teeth were clinically asymptomatic during more than 5 years follow-up. Favorable outcome was received in all cases of apicl plug formation.

CONCLUSION

MTA is highly effective for preservation of constant teeth in children with clinically complicated situations. In many cases with hopeless long-term prognosis for a teeth MTA allows stabilization of dental tissue level with the teeth being an object for guided tissue regeneration.

Clinical management of external cervical resorption: A systematic review

This review investigated whether any therapeutic options influenced the outcome of treatment for teeth with external cervical resorption. Out of 870 articles identified by an electronic search, 60 clinical case reports and six case series were included. No randomised clinical trials were found. Risk of bias was assessed using Joanna Briggs Institute's tools. External surgical intervention was the preferred method of accessing the lesions. Removal of resorptive tissue was most often achieved mechanically. Bioactive endodontic cements were the preferred materials for restoring teeth. The outcome measures were based on clinical and radiographic parameters. Of the cases included in the review, no specific treatment approach had a superior outcome in relation to Heithersay's classification. Furthermore, due to the absence of randomised clinical trials, and the low level of evidence associated with case reports/case series, it was not possible to define the optimum clinical treatment for external cervical resorption.

Immortalized cell lines derived from dental/odontogenic tissue

Stem cells derived from dental/odontogenic tissue have the property of multiple differentiation and are prospective in tooth regenerative medicine and cellular and molecular studies. However, in the face of cellular senescence soon in vitro, the proliferation ability of the cells is limited, so studies are hindered to some extent. Fortunately, immortalization strategies are expected to solve the above issues. Cellular immortalization is that cells are immortalized by introducing oncogenes, human telomerase reverse transcriptase genes (hTERT), or miscellaneous immortalization genes to get unlimited proliferation. At present, a variety of immortalized stem cells from dental/odontogenic tissue has been successfully generated, such as dental pulp stem cells (DPSCs), periodontal ligament cells (PDLs), stem cells from human exfoliated deciduous teeth (SHEDs), dental papilla cells (DPCs), and tooth germ mesenchymal cells (TGMCs). This review summarized establishment and applications of immortalized stem cells from dental/odontogenic tissues and then discussed the advantages and challenges of immortalization.

Calcium Phosphate Cement Promotes Odontoblastic Differentiation of Dental Pulp Cells In Vitro and In Vivo

In the case of pulp injury, odontoblastic differentiation of dental pulp cells (DPCs) at the site of the exposed pulp is necessary for a successful direct pulp capping treatment. Calcium phosphate cement (CPC), a kind of hydroxyapatite-like bone cement, exhibits therapeutic potential in osteogenesis by regulating cell cycle progression and promoting osteoblastic differentiation. Based on the similar biological process of osteo/odontoblastic differentiation, the present study evaluated the effects of CPC on odontoblastic differentiation of DPCs in vitro and in vivo, respectively. The morphology of CPC was observed by scanning electron microscopy. Colony-forming units were used to assess the antibacterial activity. The effects of CPC on cell proliferation and odontoblastic differentiation of human dental pulp cells (hDPCs) were also measured. Histological staining was performed to observe the reparative dentin formation in rat molars. In vitro, results of antibacterial studies showed that CPC significantly inhibited the growth of Streptococcus mutans. The appropriate concentration of CPC extract showed low cytotoxicity on hDPCs. Furthermore, CPC extract also promoted odontoblastic differentiation and mineralization compared with the control group, as shown by a dynamic increase in the expression of odontogenic marker genes and the increased number of mineralized nodules at 21 days. The pulpotomy models with CPC facilitated the formation of dentin bridge with the highly expressed dentin matrix protein 1 (DMP1) in odontoblast-like cells. In conclusion, the favorable biocompatibility, antibacterial property and bio-inductivity of CPC suggest that CPC can be used as a promising direct pulp capping material.

Physicochemical Properties, Cytocompatibility, and Biocompatibility of a Bioactive Glass Based Retrograde Filling Material

The ideal retrograde filling material that is easy to handle, has good physicochemical properties, and is biocompatible has not yet been developed. The current study reports the development of a novel bioactive glass based powder for use as a retrograde filling material that is capable of altering the consistency and hardening rate of mixtures when mixed with existing bioactive glass based cement. Furthermore, its physicochemical properties, in vitro effects on human cementoblast-like cells, and in vivo effects on inflammatory responses were evaluated. The surface of the hardened cement showed the formation of hydroxyapatite-like precipitates and calcium and silicate ions were eluted from the cement when the pH level was stabilized at 10.5. Additionally, the cement was found to be insoluble and exhibited favorable handling properties. No adverse effects on viability, proliferation, and expression of differentiated markers were observed in the in vitro experiment, and the cement was capable of inducing calcium deposition in the cells. Moreover, the cement demonstrated a lower number of infiltrated inflammatory cells compared to the other materials used in the in vivo mouse subcutaneous implantation experiment. These findings suggest that the retrograde filling material composed of bioactive glass and the novel bioactive glass based powder exhibits favorable physicochemical properties, cytocompatibility, and biocompatibility.

CTP-CM enhances osteogenic differentiation of hPDLSCs via NF-κB pathway

OBJECTIVE

The conditioned medium of calcined tooth powder (CTP-CM) is a type of biomimetic mineralized material and well contributing to bone healing and bone formation in vivo. However, little is known about the effect of CTP-CM on human periodontal ligament stem cells (hPDLSCs) as well as the underlying mechanisms.

METHODS

ALP activity assay was conducted to select the concentration with the highest ALP level, which was used for the following experiments. Cell proliferation was measured by cell counting kit-8 assay and flow cytometry analysis. Expression levels of osteogenic markers in CTP-CM-induced hPDLSCs were evaluated with real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunofluorescence staining, and Western blot. Mineralization of CTP-CM-induced hPDLSCs was evaluated by alizarin red staining. Furthermore, the involvement of NF-κB pathway was examined by immunofluorescence staining and Western blot.

RESULTS

20 μg/ml was selected for the further experiments. Functional studies demonstrated that CTP-CM exerted almost no influence on the proliferation of hPDLSCs and CTP-CM increased the osteogenic differentiation of hPDLSCs. Mechanistically, CTP-CM leads to activation of NF-κB signaling pathway. When treated with BMS345541, the osteogenic differentiation of CTP-CM-treated hPDLSCs was significantly attenuated.

CONCLUSION

CTP-CM can promote the osteogenic differentiation of hPDLSCs via activating NF-κB pathway.

The Apical Extent of Mineral Trioxide Aggregate Apical Barrier Does not Influence the Treatment Outcome in a Nonvital Immature Permanent Anterior Tooth: A Split-Mouth Clinical Study

Objective:

The study aimed to compare treatment outcomes when MTA apical plugs are placed to different apical extents in nonvital immature permanent anterior teeth with an open apex.

Methods:

Six participants (five male & one female) between the age group of 8-18 years exhibiting bilateral traumatized nonvital immature permanent maxillary anterior teeth (n=12) with non-blunderbuss canal (Cvek’s stage 4) were included. Standardized endodontic procedures were performed, and an inter-appointment calcium hydroxide medicament placed for one week. Based on the apical position of the MTA apical barrier, two study groups were defined. Accordingly, Group I {(n=6) (4mm MTA plug up to the radiographic root end)} and Group II {(n=6) (4 mm MTA plug 2 mm short of the radiographic root-end)}. Teeth were obturated after twenty-four hours with thermoplasticized gutta-percha technique. They were evaluated clinically and radiographically at 12 and 24 months. Radiographs were assessed for periapical healing based on the periapical index (PAI) scores that were dichotomized as score <3 as healed and ≥3 as not healed. The data were compared using Mann Whitney U test, Kruskal Wallis and post hoc analysis.

Results:

At 24 months, all teeth in Group I and II were healed clinically and radiographically. On inter-group comparison, radiographically, all teeth (n=12) exhibited a PAI score <3 and were categorized as healed (P=1.00).

Conclusion:

The apical extent of MTA plug does not influence the treatment outcome. The clinician can place MTA apical plug either up to or 2 mm short of the radiographic root-end.

Performance of the dentogingival junction with mta and biodentine on the treatment of invasive cervical resorptions. A literature review and case report

Invasive cervical resorption (ICR) is an uncommon phenomenon (0.1%), however, it represents a challenge to the structural and functional integrity of the dentogingival junction, as well as a risk for the survival of the affected tooth. They are characterized by their location and invasive character, being able to appear in any tooth of the permanent dentition. It shows up after the damage to the cervical insertion apparatus, leaving the pulp without participation in the origin of the lesion. They may appear just below the junctional epithelium or at a more apical level. The MTA® (Dentsply, Tulsa dental, Tulsa OK) and the Biodentine® (Septodent, Saint Maur of Fossés, France) are two biomaterials that have demonstrated the ability to promote the neoformation of cement so they are considered an alternative in the treatment of the ICR. This article presents an ICR clinical cases treated with these biomaterials, in which favorable post-operative healing is observed.

Key words:MTA, Biodentine, biomaterials, root resorption, invasive cervical resorption.

The effects of mineral trioxide aggregate on osteo/odontogenic potential of mesenchymal stem cells: a comprehensive and systematic literature review

The significance of dental materials in dentin-pulp complex tissue engineering is undeniable. The mechanical properties and bioactivity of mineral trioxide aggregate (MTA) make it a promising biomaterial for future stem cell-based endodontic therapies. There are numerous in vitro studies suggesting the low cytotoxicity of MTA towards various types of cells. Moreover, it has been shown that MTA can enhance mesenchymal stem cells' (MSCs) osteo/odontogenic ability. According to the preferred reporting items for systematic reviews and meta-analyses (PRISMA), a literature review was conducted in the Medline, PubMed, and Scopus databases. Among the identified records, the cytotoxicity and osteo/odontoblastic potential of MTA or its extract on stem cells were investigated. Previous studies have discovered the differentiation-inducing potential of MTA on MSCs, providing a background for dentin-pulp complex cell therapies using the MTA, however, animal trials are needed before moving into clinical trials. In conclusion, MTA can be a promising candidate dental biomaterial for futuristic stem cell-based endodontic therapies.

Chemerin/ChemR23 regulates cementoblast function and tooth resorption in mice via inflammatory factors

BACKGROUND

Periodontitis and orthodontic treatment can lead to inflammatory root resorption (IRR) through an unclear mechanism. Chemerin, a novel chemoattractant protein, is closely associated with inflammation, affects osteoblast and osteoclast differentiation, and may play a role in IRR. We aimed to explore possible roles of the chemerin/ChemR23 interaction in cementoblast function and IRR and reveal a new IRR therapeutic target.

METHODS

Cementoblast function-related gene and protein expression in the immortalized murine cementoblast cell line OCCM-30 after treatment with chemerin and siChemR23 was examined by qRT-PCR and Western blotting.The roles of the MAPK and PI3K-Akt signaling pathways were studied using specific inhibitors. Cementoblast cytokine production under different treatment conditions was measured by ELISA and qRT-PCR. Additionally, we modeled IRR in wild-type and chemerin-overexpressing mice and injected transgenic mice with anti-ChemR23 antibody to block ChemR23. We then calculated the root resorption volume and examined periodontal tissue cathepsin K, Runx2, TNF-α, and IL-6 expression.

RESULT

Chemerin suppressed cementoblast differentiation and mineralization and exerted a proinflammatory effect on cementoblasts. These effects were partially reversed by siChemR23 and reversed to different extents by p38, Erk1/2 and PI3K-Akt pathway inhibition, suggesting p38, Erk1/2 and PI3K-Akt pathways as signaling pathways downstream of chemerin/ChemR23. In vivo, chemerin overexpression worsened IRR. Moreover, chemerin expression was positively correlated with TNF-α, IL-6, and cathepsin K expression and negatively correlated with Runx2 expression. ChemR23 downregulation reversed these effects.

CONCLUSION

Chemerin/ChemR23 induced TNF-α and IL-6 expression dependent on Erk1/2, p38 MAPK and PI3K-Akt signaling pathway activation, thereby regulating cementoblast function and affecting IRR. This article is protected by copyright. All rights reserved.

The Disease Process, Diagnosis and Treatment of Invasive Cervical Resorption: A Review

Invasive cervical resorption (ICR) is a localized, subepithelial, supra-osseous resorptive process of the tooth. Although there are several predisposing factors associated with ICR, its etiology and pathogenesis are poorly understood. The damage to the protective layer on the external root surface appears to allow for the attachment of clastic cells and initiate the resorptive process, which is confined by the inner protective pericanalar resorption-resistant sheet surrounding the root canal space. The use of cone-beam computed tomography (CBCT) is recommended for the diagnosis and assessment of a resorptive lesion. Based on the thorough evaluation of the size and location of the ICR lesion using CBCT, surgical or nonsurgical treatment can be chosen to address the source of the resorption. This review discusses the current status of knowledge regarding the biology of ICR lesions as well as their external or internal treatment using hydraulic calcium silicate-based materials. Future clinical outcome studies are necessary to evaluate the impact of hydraulic calcium silicate-based materials on the healing of ICR lesions.

Warm Gutta-Percha Techniques Regulate Cell Viability, Heat Shock, and Mineralized Tissue-associated Proteins of Cementoblasts

INTRODUCTION

The aim of this study was to determine the effect of the continuous wave of condensation technique (CWCT) and the thermoplastic gutta-percha injection (TGI) technique on the messenger RNA (mRNA) expressions of heat shock proteins (HSPs) and mineralized tissue-associated proteins of the immortalized mouse cementoblasts (OCCM.30).

METHODS

Crowns of human premolar teeth with single and straight canals were removed. The root canals were prepared up to the ProTaper Next X5 file (Dentsply Maillefer, Ballaigues, Switzerland) in combination with 2 mL 2.5% sodium hypochlorite solution. Roots (12 ± 2 mm height) were sterilized (121°C for 20 minutes) and placed vertically to the cell culture dishes using a tissue culture insert by opening holes according to the root diameter after the removal of 1 mm from the apex for appropriate adaptation to the petri dish surfaces. Six groups were created: control 1 (without teeth), control 2 (with teeth), AH Plus (Dentsply DeTrey, Konstanz, Germany), single-cone obturation (SC), CWCT, and thermoplastic gutta-percha injection technique (TGI). The viability of the OCCM.30 cells was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability experiments at 24 and 96 hours. The mRNA expression of HSP27, HSP70, and HSP90 and mineralized tissue markers (bone sialoprotein, osteocalcin, runt-related transcription factor 2, type I collagen, and alkaline phosphatase) was evaluated by real-time polymerase chain reaction.

RESULTS

Reduced OCCM.30 cell viability was observed in all groups except the control groups. When the SC technique and CWCT and TGI groups were compared, it was observed that heat had a significant negative effect on cell viability (P < .05). A reduction in the mRNA expressions of HSP27, HSP70, and HSP90 was recognized in all test groups when compared with the control 1 group (P < .01). When the warm gutta-percha techniques were compared with the SC technique, a decrease in mRNA expression of HSP27 and HSP90 was noted (P < .01). The HSP70 transcript was similar in the CWCT group and the SC group. Higher HSP70 mRNA expression was observed in the TGI group compared with the SC group. In all groups except the control 1 group, bone sialoprotein, osteocalcin, runt-related transcription factor 2, type I collagen, and alkaline phosphatase mineralized tissue markers were affected, but this negative effect was higher in the heat-treated groups (P < .05).

CONCLUSIONS

Within the limitations of this study, it was concluded that warm gutta-percha techniques reduced the mRNA expressions of the genes for HSPs and mineralized tissue-associated proteins of cementoblasts. Further animal studies are needed to clarify the effect of heat on the behavior of cementoblasts histologically in short- and long-term periods.

Outcome of Root Canal Treatments Using a New Calcium Silicate Root Canal Sealer: A Non-Randomized Clinical Trial

Background: The aim of this study was to compare the success rate of root canal treatments undertaken using a calcium silicate root canal sealer in combination with a single cone with non-calcium silicate cement and warm vertical condensation. Methods: 150 necrotic or pulpitic teeth were treated. (REC: 08/H0804/79). Following standardized root canal chemo-debridement. The canals were obturated using warm vertical condensation of gutta-percha and epoxy-based sealer (AH plus) or a calcium silicate sealer (BioRoot^TM RCS) with a single cone technique. Follow-up assessment was conducted at 12 months using Cone Beam Computed Tomography (CBCT). Results: At 1-year recall, 104 teeth were assessed (51 AH plus, 53 BioRoot^TM RCS). The success rate using loose criteria for the CBCT images and PA radiographs was respectively 80% and 89% in the AH plus/warm vertical condensation group, 84% and 90% in the BioRoot^TM RCS/single cone group. There was no statistically significant difference between the two groups (Fisher exact test p value 0.6099 for the CBCT images). Conclusion: Within the limitations of this non-randomized trial, a calcium silicate cement in combination with single cone resulted in a similar proportion of successful cases compared to warm vertical condensation and epoxy-based sealer.

Vital Pulp Therapy an Insight Over the Available Literature and Future Expectations

Vital pulp therapy (VPT) defined as “treatment which aims at preserving and maintaining the pulp tissue that has been compromised but not destroyed by extensive dental caries, dental trauma, and restorative procedures or for iatrogenic reasons”, offers some beneficial advantages over the conventional root canal treatment such as protective resistance for mastication forces or to prevent the loss of environmental changes sensation ability, which can lead to unnoticeable progression of caries and later fracture. A wide range of materials are suggested in the literature to be used as pulp capping protective dressing materials that varies from ready-made synthetic materials to biological based scaffolds and composites. The aim of the present review is to provide a full understanding of currently used materials to clinicians in order to help in their decision-making process delivering the best available evidence-based treatments to their patients. An extensive search for recent available data regarding direct pulp capping materials and potential suggestions for future use have been made. Newly developed biological based scaffolds showed promising results in dentine regeneration therefore strengthening the tooth structure and overcoming potential drawbacks of use of currently available recommended materials.

Effects of ERK/p38 MAPKs signaling pathways on MTA-mediated osteo/odontogenic differentiation of stem cells from apical papilla: a vitro study

BACKGROUND

Stem cells from apical papilla (SCAP) located in the root apex of immature permanent teeth are a reliable cell source for pulp-dentine complex regeneration. Mineral trioxide aggregate (MTA) is a biocompatible material which has been widely used in endodontic treatments. The aim of this study was to elucidate the regulatory role of MTA in the proliferation and differentiation of SCAP.

METHODS

Cell viability was detected by Cell counting kit-8. Characteristics of SCAP were confirmed by Flow cytometric (FCM) analysis and alizarin red staining. Then, MTA-mediated osteo/odontogenic differentiation of SCAP was investigated by reverse transcription polymerase chain reaction. The effect of MAPKs on MTA-mediated osteo/odontogenic differentiation was evaluated by western blot analysis.

RESULTS

There was no significant difference in cell viability between the control group and the group with lower concentrations of MTA. However, higher concentrations of MTA could inhibit proliferation of SCAP. It is demonstrated that the ALP activity were enhanced, the mRNA and protein expression of BSP, OCN, DSPP, Runx2 were up-regulated. In addition, phosphorylation proteins of ERK, p38 were activated through western blot analysis.

CONCLUSIONS

MTA at appropriate concentration could enhance osteo/odontogenic differentiation of SCAP by activating p38 and ERK signaling pathways. This study provides a new idea for the clinical application of MTA and the treatment of endodontic diseases.

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

AIM

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

Combination of mineral trioxide aggregate and propolis promotes odontoblastic differentiation of human dental pulp stem cells through ERK signaling pathway

The aim of this study is to investigate combined effects of mineral trioxide aggregate (MTA) and propolis on odontoblastic differentiation of human dental pulp stem cells (DPSCs) and to find a signaling pathway involved. Combination of MTA and propolis significantly up-regulated the expression of DSPP and DMP1, and facilitated a mineral nodule formation (p < 0.05). Treatments with MTA, propolis or combined increased the phosphorylation of extracellular signal-regulated kinases (ERK), one of mitogen-activated protein kinases signaling cascades during odontogenic differentiation of DPSCs (p < 0.05), and U0126, an inhibitor of ERK, decreased calcium deposits (p < 0.05). Combination of MTA and propolis promotes odontogenic differentiation and mineralization of DPSCs through ERK pathway.

Yunnan Baiyao Conditioned Medium Promotes the Odonto/Osteogenic Capacity of Stem Cells from Apical Papilla via Nuclear Factor Kappa B Signaling Pathway

Yunnan Baiyao is a traditional Chinese herbal remedy that has long been used for its characteristics of wound healing, bone regeneration, and anti-inflammation. However, the effects of Yunnan Baiyao on the odonto/osteogenic differentiation of stem cells from apical papilla (SCAPs) and the potential mechanisms remain unclear. The aim of this study was to investigate the odonto/osteogenic differentiation effects of Yunnan Baiyao on SCAPs and the underlying mechanisms involved. SCAPs were isolated and cocultured with Yunnan Baiyao conditioned media. The proliferation ability was determined by cell counting kit 8 and flow cytometry. The differentiation capacity and the involvement of NF-κB pathway were investigated by alkaline phosphatase assay, alizarin red staining, immunofluorescence assay, real-time RT-PCR, and western blot analyses. Yunnan Baiyao conditioned medium at the concentration of 50 μg/mL upregulated alkaline phosphatase activity, induced more mineralized nodules, and increased the expression of odonto/osteogenic genes/proteins (e.g., OCN/OCN, OPN/OPN, OSX/OSX, RUNX2/RUNX2, ALP/ALP, COL-I/COL-I, DMP1, DSP/DSPP) of SCAPs. In addition, the expression of cytoplasmic phos-IκBα, phos-P65, and nuclear P65 was significantly increased in Yunnan Baiyao conditioned medium treated SCAPs in a time-dependent manner. Conversely, the differentiation of Yunnan Baiyao conditioned medium treated SCAPs was obviously inhibited when these stem cells were cocultured with the specific NF-κB inhibitor BMS345541. Yunnan Baiyao can promote the odonto/osteogenic differentiation of SCAPs via the NF-κB signaling pathway.

The Conditioned Medium of Calcined Tooth Powder Promotes the Osteogenic and Odontogenic Differentiation of Human Dental Pulp Stem Cells via MAPK Signaling Pathways

The calcined tooth powder (CTP), a type of allogeneic biomimetic mineralized material, has been confirmed that can promote new bone formation when obtained at high temperature. The aim of this study was to investigate effects of the conditioned medium of calcined tooth powder (CTP-CM) on the osteogenic and odontogenic differentiation of human dental pulp stem cells (hDPSCs) and the underlying mechanisms involved. First, ALP activity assay determined that 200 μg/mL was the optimal concentration of CTP-CM for the following experiments. CTP-CM had no significant effect on the proliferation of hDPSCs as indicated by CCK-8 and FCM analysis. Both the gene and protein (DSPP/DSPP, RUNX2/RUNX2, OCN/OCN, OSX/OSX, OPN/OPN, ALP/ALP, and COL-1/COL-1) expression levels increased in the CTP-CM-induced hDPSC group as compared with those in the control group at day 3 or 7, showing the positive regulation of CTP-CM on the osteo/odontogenic differentiation of hDPSCs. Mechanistically, MAPK signaling pathways were activated after the CTP-CM treatment, and the inhibitors targeting MAPK were identified which weakened the effects of CTM-CM on the committed differentiation of hDPSCs. These findings could lead to the creation of stem cell therapies for dental regeneration.

Axl Involved in Mineral Trioxide Aggregate Induces Macrophage Polarization

INTRODUCTION

In this study, we examined the effect of mineral trioxide aggregate (MTA) on macrophage polarization and the potential involvement of Axl/nuclear factor kappa B (NF-κB) signaling in mediating the effect of MTA.

METHODS

The human monocyte cell line THP-1 was cultured with MTA solution for 1, 2, or 3 days, and the population change of M2 macrophages was analyzed by flow cytometry. Expression of M2 cytokines was examined by enzyme-linked immunosorbent assay. Phagocytosis and angiogenesis-induction ability were also assayed. The involvement of Axl/NF-κB signaling in MTA-treated cells was examined by analyzing phosphorylation status of Axl, Akt, IKKα/β, and IκBα. Specific inhibitors for Axl/Akt/NF-κB signaling were added to MTA-treated THP-1 cells, and their cytokine expression change was examined.

RESULTS

Flow cytometry analysis showed that MTA treatment increased CD206＋ cells in a time-dependent way. After MTA treatment, the expression of M2-related cytokines was up-regulated. MTA also enhanced phagocytic ability and the ability of THP-1 cells to induce angiogenesis. Treatment of MTA led to activate Axl/Akt/NF-kB signal axis by phosphorylation of Axl, Akt, IKKα/β, IκBα, and p65. In addition, MTA-induced interleukin 10, transforming growth factor beta, and vascular endothelial growth factor expression was suppressed as specific inhibitors were added.

CONCLUSIONS

Our findings indicate that MTA is able to induce macrophage polarization toward the M2 phenotype, with up-regulation of interleukin 10, transforming growth factor beta, and vascular endothelial growth factor, and that Axl/Akt/NF-κB signaling participates in this process. These results provide the cellular and molecular basis of MTA's anti-inflammatory action in clinical applications.

Nano Hydroxyapatite & Mineral Trioxide Aggregate Efficiently Promote Odontogenic Differentiation of Dental Pulp Stem Cells

BACKGROUND:

There has been an urge to shift from conventional therapies to the more promising regenerative strategy since conventional treatment relies on synthetic materials to fill defects and replace missing tissues, lacking the ability to restore the tissues’ physiological architecture and function.

AIM:

The present study focused on the assessment of the role of two commonly used biomaterials namely; mineral trioxide aggregate (MTA) and nano hydroxy-apatite as promoters of odontogenic differentiation of dental pulp stem cells (DPSCs).

METHODS:

DPSCs were isolated, cultured in odontogenic media and divided into three groups; control group, MTA group and nanohydroxyapatite group. Odontogenic differentiation was assessed by tracing genes characteristic of different stages of odontoblasts via qRT-PCR. Calcific nodules formation was evaluated by Alizarin red staining.

RESULTS:

Results demonstrated that both MTA and nanohydroxyapatite were capable of enhancing odontogenic differentiation of DPSCs.

CONCLUSION:

Nano hydroxyapatite was found to have a higher promoting effect. However, in the absence of an odontogenic medium, MTA and nanohydroxyapatite could not enhance the odontogenic differentiation of DPSCs.

The Effect of Commercially Available Endodontic Cements and Biomaterials on Osteogenic Differentiation of Dental Pulp Pluripotent-Like Stem Cells

The aim of this study is to compare the osteogenic differentiation capacity of the dental pulp pluripotent-like stem cells (DPPSCs) using conditional media pretreated with ProRoot-MTA, Biodentine (BD) or the newly manufactured pure Portland cement Med-PZ (MZ). DPPSCs, isolated from human third molars, are the most relevant cell model to draw conclusions about the role of biomaterials on dental tissue regeneration. Cytotoxicity, alkaline phosphatase (ALP) activity, and calcium deposition analysis were evaluated at different differentiation time points. Gene expression of key osteogenic markers (RUNX2, Collagen I and Osteocalcin) was determined by qRT-PCR analysis. The osteogenic capacity of cells cultured in conditioned media prepared from MZ or MTA cements was comparable. BD conditioned media supported cell proliferation but failed to induce osteogenesis. Relative to controls and other cements, high osteogenic gene expression was observed in cultures pre-treated with the novel endodontic cement MZ. In conclusion, the in vitro behavior of a MZ- endodontic cement was evaluated, showing similar enhanced cell proliferation compared to other commercially available cements but with an enhanced osteogenic capacity with prospective potential as a novel cement for endodontic treatments.

Interleukin-17A promotes osteogenic differentiation by increasing OPG/RANKL ratio in stem cells from human exfoliated deciduous teeth (SHED)

Stem cells derived from human exfoliated deciduous teeth (SHED) represent a promising cell source for bone tissue regeneration. This study evaluated the effects of interleukin-17A (IL-17A) on the osteogenic differentiation of SHED. SHED were cultured in complete alpha minimum essential medium supplemented with osteoinducing reagents and treated with recombinant IL-17A. The cells were quantitatively analysed for proliferative activity by MTS assay, cell markers expression, and apoptotic activity by flow cytometry. For osteogenic differentiation, alkaline phosphatase (ALP) activity was quantified; mineralization assays were carried out using von Kossa and Alizarin red, and expression of osteogenic markers were analysed by real-time polymerase chain reaction and Western blot. The results showed that treatment with IL-17A increased proliferative activity in a dose-dependent manner, but reduced the expression of stem cell markers (c-Myc and Nanog) as the days progressed. IL-17A induced osteogenic differentiation in SHED as evidenced by high ALP activity, increased matrix mineralization, and upregulation of the mRNA expression of the osteogenic markers ALP, alpha 1 type 1 collagen (Col1A1), runt-related transcription factor 2 (RUNX2), osteopontin (OPN), osteocalcin (OCN), and osteoprotegerin (OPG) but downregulation of receptor activator of nuclear factor κB ligand (RANKL) as well as altering the OPG/RANKL ratio. Findings from our study indicate that IL-17A enhances proliferation and osteogenic differentiation of SHED by regulating OPG/RANKL mechanism thus suggests therapeutic potential of IL-17A in bone regeneration.

Evaluation of the bioactivity of fluoride-enriched mineral trioxide aggregate on osteoblasts

AIM

To investigate whether a combination of mineral trioxide aggregate (MTA) and fluoride compounds affects bone cells.

METHODOLOGY

Mineral trioxide aggregate (MTA) discs (ProRoot^® , Dentsply Sirona, Ballaigues, Switzerland) with and without the addition of 0.1%, 0.25% and 0.5% sodium fluoride were characterized for their surface roughness by laser scanning microscopy and for the adhesion of human alveolar osteoblasts by scanning electron microscopy. Using eluates from fluoride-enriched MTA discs, the cell proliferation was measured by monitoring the DNA incorporation of 5-bromo-2'-deoxyuridine. Further, gene expression was evaluated by qPCR arrays, extracellular matrix mineralization was quantified by absorption measurement of Alizarin red stains, and effects were calculated with repeated measures analysis and post hoc P-value adjustment.

RESULTS

Irrespective of fluoride addition, cell adhesion was similar on MTA discs, of which the surface roughness was comparable. Control osteoblasts had a curvilinear proliferation pattern peaking at d5, which was levelled out by incubation with MTA. The addition of fluoride partly restored the MTA-related reduction in the cellular proliferation rate in a dose-dependent manner. At the mRNA level, both fluoride and MTA modulated a number of genes involved in osteogenesis, bone mineral metabolism and extracellular matrix formation. Although MTA significantly impaired extracellular matrix mineralization, the addition of fluoride supported the formation of mineralized nodules in a dose-dependent manner.

CONCLUSION

The addition of fluoride modulated the biocompatibility of MTA in terms of supporting bone cell proliferation and hard tissue formation. Hence, fluoride enrichment is a trend-setting advancement for MTA-based endodontic therapies.

Ice-Templated Protein Nanoridges Induce Bone Tissue Formation

Little is known about the role of biocompatible protein nanoridges in directing stem cell fate and tissue regeneration due to the difficulty in forming protein nanoridges. Here an ice-templating approach is proposed to produce semi-parallel pure silk protein nanoridges. The key to this approach is that water droplets formed in the protein films are frozen into ice crystals (removed later by sublimation), pushing the surrounding protein molecules to be assembled into nanoridges. Unlike the flat protein films, the unique protein nanoridges can induce the differentiation of human mesenchymal stem cells (MSCs) into osteoblasts without any additional inducers, as well as the formation of bone tissue in a subcutaneous rat model even when not seeded with MSCs. Moreover, the nanoridged films induce less inflammatory infiltration than the flat films in vivo. This work indicates that decorating biomaterials surfaces with protein nanoridges can enhance bone tissue formation in bone repair.

Effect of iRoot Fast Set root repair material on the proliferation, migration and differentiation of human dental pulp stem cells in vitro

The present study investigated the effect of iRoot Fast Set root repair material (iRoot FS) on the proliferation, migration and differentiation of human dental pulp stem cells (hDPSCs). The hDPSCs were treated with eluates of iRoot FS at concentrations of 0.2 and 2 mg/mL, referred to as FS0.2 and FS2, respectively, and Biodentine (BD; Septodont, Saint Maur des Faussés, France) eluates at the corresponding concentrations as positive controls. A CCK8 assay was performed to determine cell proliferation. Wound healing and transwell assays were conducted to examine cell migration. Osteogenic differentiation was evaluated based on alkaline phosphatase activity, Alizarin Red S staining and quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) to analyze the mRNA expression of differentiation gene markers. Cell proliferation was higher in the FS and BD groups than in the blank controls at 3 and 7 days. Moreover, FS0.2 enhanced cell migration and significantly promoted the osteogenic differentiation of hDPSCs. These findings suggested that iRoot FS is a bioactive material that promotes the proliferation, migration and osteogenic differentiation of hDPSCs.

Mineral trioxide aggregate improves healing response of periodontal tissue to injury in mice

BACKGROUND AND OBJECTIVE

Mineral trioxide aggregate (MTA) is a biomaterial used in endodontic procedures as it exerts beneficial effects on regenerative processes. In this study, we evaluate the effect of MTA on healing of periodontal ligament (PDL) and surrounding tissue, following injury, in a transgenic mouse model and on the differentiation of murine mesenchymal progenitor cells in vitro.

MATERIAL AND METHODS

We used an inducible Cre-loxP in vivo fate mapping approach to examine the effects of MTA on the contributions of descendants of cells expressing the αSMA-CreERT2 transgene (SMA9⁺ ) to the PDL and alveolar bone after experimental injury to the root furcation on the maxillary first molars. Col2.3GFP was used as a marker to identify mature osteoblasts, cementoblasts and PDL fibroblasts. The effects of MTA were examined 2, 17 and 30 days after injury and compared histologically with sealing using an adhesive system. The effects of two dilutions of medium conditioned with MTA on proliferation and differentiation of mesenchymal progenitor cells derived from bone marrow (BMSC) and periodontal ligament (PDLC) in vitro were examined using the PrestoBlue viability assay, alkaline phosphatase and Von Kossa staining. The expression of markers of differentiation was assessed using real-time PCR.

RESULTS

Histological analyses showed better repair in teeth restored with MTA, as shown by greater expansion of SMA9⁺ progenitor cells and Col2.3GFP⁺ osteoblasts compared with control teeth. We also observed a positive effect on differentiation of SMA9⁺ progenitors into osteoblasts and cementoblasts in the apical region distant from the site of injury. The in vitro data showed that MTA-conditioned medium reduced cell viability and osteogenic differentiation in both PDLC and BMSC, indicated by reduced von Kossa staining and lower expression of osteocalcin and bone sialoprotein. In addition, cultures grown in the presence of MTA had marked decreases in SMA9⁺ and Col2.3GFP⁺ areas as compared with osteogenic medium, confirming reduced osteogenesis.

CONCLUSION

MTA promotes regeneration of injured PDL and alveolar bone, reflected as contribution of progenitors (SMA9⁺ cells) into osteoblasts (Col2.3GFP⁺ cells). In vitro, MTA-conditioned medium fails to promote osteogenic differentiation of both PDLC and BMSC.

Graphene Nanosheets to Improve Physico-Mechanical Properties of Bioactive Calcium Silicate Cements

Bioactive calcium silicate cements are widely used to induce mineralization, to cement prosthetic parts, in the management of tooth perforations, and other areas. Nonetheless, they can present clinical disadvantages, such as long setting time and modest physico-mechanical properties. The objective of this work was to evaluate the potential of graphene nanosheets (GNS) to improve two bioactive cements. GNS were obtained via reduction of graphite oxide. GNS were mixed (1, 3, 5, and 7 wt %) with Biodentine (BIO) and Endocem Zr (ECZ), and the effects on setting time, hardness, push-out strength, pH profile, cell proliferation, and mineralization were evaluated. Statistics were performed with two-way ANOVA and Tukey test (α = 0.05). GNS has not interfered in the composition of the set cements as confirmed by Raman, FT-IR and XRD. GNS (1 and 3 wt %) shortened the setting time, increased hardness of both materials but decreased significantly the push-out strength of ECZ. pH was not affected but 1 wt % and 7 wt % to ECZ and 5 wt % to BIO increased the mineralization compared to the controls. In summary, GNS may be an alternative to improve the physico-mechanical properties and bioactivity of cements. Nonetheless, the use of GNS may not be advised for all materials when effective bonding is a concern.

Portland cement induces human periodontal ligament cells to differentiate by upregulating miR-146a

BACKGROUND/PURPOSE

Bioaggregates such as Portland cement (PC) can be an economical alternative for mineral trioxide aggregate (MTA) with additional benefit of less discoloration. MTA has been known to induce differentiations of several dental cells. MicroRNAs are important regulators of biological processes, including differentiation, physiologic homeostasis, and disease progression. This study is to explore how PC enhances the differentiation of periodontal ligament (PDL) cells in microRNAs level.

METHODS

PDL cells were cultured in a regular PC- or MTA-conditioned medium or an osteoinduction medium (OIM). Alizarin red staining was used to evaluate the extent of mineralization. Transfection of microRNA mimics induced exogenous miR-31 and miR-146a expression. The expression of microRNAs and differentiation markers was assayed using reverse-transcriptase polymerase chain reaction.

RESULTS

PC enhanced the mineralization of PDL cells in a dose-dependent manner in the OIM. Exogenous miR-31 and miR-146a expression upregulated alkaline phosphatase (ALP), bone morphogenic protein (BMP), and dentin matrix protein 1 (DMP1) expression. However, miR-31 and miR-146a modulates cementum protein 1 (CEMP1) expression in different ways. PC also enhanced ALP and BMP but attenuated CEMP1 in the OIM. Although the OIM or PC treatment upregulated miR-21, miR-29b, and miR-146a, only miR-146a was able to be induced by PC in combination with OIM.

CONCLUSION

This study demonstrated that PC enhances the differentiation of PDL cells, especially osteogenic through miR-146a upregulation. In order to control the ankylosis after regenerative endodontics with the usage of bioaggregates, further investigations to explore these differentiation mechanisms in the miRNA level may be needed.

Intermittent parathyroid hormone (PTH) promotes cementogenesis and alleviates the catabolic effects of mechanical strain in cementoblasts

Background

External root resorption, commonly starting from cementum, is a severe side effect of orthodontic treatment. In this pathological process and repairing course followed, cementoblasts play a significant role. Previous studies implicated that parathyroid hormone (PTH) could act on committed osteoblast precursors to promote differentiation, and inhibit apoptosis. But little was known about the role of PTH in cementoblasts. The purpose of this study was to investigate the effects of intermittent PTH on cementoblasts and its influence after mechanical strain treatment.

Results

Higher levels of cementogenesis- and differentiation-related biomarkers (bone sialoprotein (BSP), osteocalcin (OCN), Collagen type I (COL1) and Osterix (Osx)) were shown in 1–3 cycles of intermittent PTH treated groups than the control group. Additionally, intermittent PTH increased alkaline phosphatase (ALP) activity and mineralized nodules formation, as measured by ALP staining, quantitative ALP assay, Alizarin red S staining and quantitative calcium assay. The morphology of OCCM-30 cells changed after mechanical strain exertion. Expression of BSP, ALP, OCN, osteopontin (OPN) and Osx was restrained after 18 h mechanical strain. Furthermore, intermittent PTH significantly increased the expression of cementogenesis- and differentiation-related biomarkers in mechanical strain treated OCCM-30 cells.

Conclusions

Taken together, these data suggested that intermittent PTH promoted cementum formation through activating cementogenesis- and differentiation-related biomarkers, and attenuated the catabolic effects of mechanical strain in immortalized cementoblasts OCCM-30.

Electronic supplementary material

The online version of this article (doi:10.1186/s12860-017-0133-0) contains supplementary material, which is available to authorized users.

Shear bond strength of different restorative materials to mineral trioxide aggregate and Biodentine

Significance of Study:

Mineral trioxide aggregate (MTA) and Biodentine (calcium silicate-based materials) have great importance in dentistry. There is no study comparing the bond strength of Biodentine and MTA for composite, compomer, and compomer or resin-modified glass ionomer (RMGIC). Although many advantages of Biodentine over MTA; in this study, MTA has shown better shear bond strength (SBS) to restorative materials.

Aim:

Recently, a variety of calcium silicate-based materials are often used for pulp capping, perforation repair, and endodontic therapies. After those treatment procedures, teeth are commonly restored with composite resin, (RMGIC materials in pediatric dentistry. The aim of this study was to evaluate the SBS of composite resin (Filtek™ Z250; 3M ESPE, USA), compomer (Dyract XP; LD Caulk/Dentsply, USA), and resin-modified glass ionomer (Photac-Fil Quick Aplicap; 3M ESPE, USA) to white MTA and Biodentine.

Materials and Methods:

Ninety acrylic cylindrical blocks were prepared and divided into two groups (n = 45). The acrylic blocks were randomly allocated into 3 subgroups; Group-1A: MTA + composite (Filtek™ Z250), Group-1B: MTA + compomer (Dyract XP), Group-1C: MTA + RMGIC (Photac-Fil Quick Aplicap), Group-2A: Biodentine + composite, Group-2B: Biodentine + compomer, Group-2C: Biodentine + RMGIC. The specimens were mounted in Universal Testing Machine. A crosshead speed 1 mm/min was applied to each specimen using a knife-edge blade until the bond between the MTA/Biodentine and restorative material failed. Failure modes of each group were evaluated under polarized light microscope at ×40 magnification.

Results:

There was no statistically significant difference between MTA + Composite resin with MTA + Compomer; and MTA + RMGIC with Biodentine + RMGIC (P > 0.05). There were statistically significant differences between other groups (P < 0.05).

Conclusions:

The results of the present study displayed that although many advantages of Biodentine over MTA; MTA has shown better SBS to compomer and composite resin materials than Biodentine.

Altered Apical Morphology (Reverse Architecture): Use of Indirect Ultrasonic Technique for Orthograde MTA Placement in Maxillary Premolars

Aim. To report the management and orthograde technique of MTA placement in case of reverse architecture maxillary premolars. Summary. Two cases of 17-year-old and 21-year-old female patients were referred to endodontic speciality for management of maxillary premolar having reverse architecture with wide immature open apex like a bell mouth. In both the cases, after control of intraradicular infection, it was decided to use MTA for apexification and obturation of canals. Orthograde placement of MTA is a challenging procedure in terms of length control and condensation especially in divergent irregular reverse architecture wide open apex. A novel technique with the help of finger plugger, sterilized paper point, and ultrasonic agitation for 3D compaction of MTA at apical reverse architecture was used. Thickening of the canal wall and complete apical closure were confirmed one year after the treatment.

Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

OBJECTIVE

To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water.

MATERIAL AND METHODS

White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey's post-hoc analysis (a=0.05).

RESULTS

The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0.

CONCLUSION

Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA.

Cementoblastic lineage formation in the cross-talk between stem cells of human exfoliated deciduous teeth and epithelial rests of Malassez cells

OBJECTIVES

The purpose of this study was to evaluate the synergistic effect of epithelial rests of Malassez cells (ERM) and transforming growth factor-β1 (TGF-β1) on proliferation, cementogenic and osteogenic differentiation of stem cells derived from human exfoliated deciduous teeth (SHED).

MATERIALS AND METHODS

SHED were co-cultured with ERM with/without TGF-β1. Then, SHED proliferation, morphological appearance, alkaline phosphatase (ALP) activity, mineralization behaviour and gene/protein expression of cemento/osteoblastic phenotype were evaluated.

RESULTS

TGF-β1 enhanced SHED proliferation when either cultured alone or co-cultured with ERM. ERM induced the cementoblastic differentiation of SHED which was significantly accelerated when treated with TGF-β1. This activity was demonstrated by high ALP activity, strong mineral deposition and upregulation of cementum/bone-related gene and protein expressions (i.e. ALP, collagen type I, bone sialoprotein, osteocalcin and cementum attachment protein).

CONCLUSIONS

ERM were able to induce SHED differentiation along the cemento/osteoblastic lineage that was triggered in the presence of TGF-β1.

CLINICAL RELEVANCE

The cemento/osteoblastic differentiation capability of SHED possesses a therapeutic potential in endodontic and periodontal tissue engineering.

Cementoblastic lineage formation in the cross-talk between stem cells of human exfoliated deciduous teeth and epithelial rests of Malassez cells

OBJECTIVES

The purpose of this study was to evaluate the synergistic effect of epithelial rests of Malassez cells (ERM) and transforming growth factor-β1 (TGF-β1) on proliferation, cementogenic and osteogenic differentiation of stem cells derived from human exfoliated deciduous teeth (SHED).

MATERIALS AND METHODS

SHED were co-cultured with ERM with/without TGF-β1. Then, SHED proliferation, morphological appearance, alkaline phosphatase (ALP) activity, mineralization behaviour and gene/protein expression of cemento/osteoblastic phenotype were evaluated.

RESULTS

TGF-β1 enhanced SHED proliferation when either cultured alone or co-cultured with ERM. ERM induced the cementoblastic differentiation of SHED which was significantly accelerated when treated with TGF-β1. This activity was demonstrated by high ALP activity, strong mineral deposition and upregulation of cementum/bone-related gene and protein expressions (i.e. ALP, collagen type I, bone sialoprotein, osteocalcin and cementum attachment protein).

CONCLUSIONS

ERM were able to induce SHED differentiation along the cemento/osteoblastic lineage that was triggered in the presence of TGF-β1.

CLINICAL RELEVANCE

The cemento/osteoblastic differentiation capability of SHED possesses a therapeutic potential in endodontic and periodontal tissue engineering.

Stimulating effect of a novel synthesized sulfonamido-based gallate ZXHA-TC on primary osteoblasts

PURPOSE

This study is intended to investigate the effects of plants or plant-derived antioxidants on prevention of osteoporosis through the maintenance of reactive oxygen species (ROS) at a favorable level.

MATERIALS AND METHODS

In this study, a novel antioxidant, namely 3,4,5-Trihydroxy-N-[4-(5-hydroxy-6-methoxy-pyrimidin-4-ylsulfamoyl)-phenyl]-benzamide (ZXHA-TC) was synthesized from gallic acid and sulfadimoxine. Its effect on osteoblast metabolism was investigated via the detection of cell proliferation, cell viability, production of ROS, and expression of osteogenic-specific genes including runt-related transcription factor 2 (RUNX2), bone sialoprotein (BSP), osteocalcin (OCN), alpha-1 type I collagen (COL1A1), and osteogenic-related proteins after treatment for 2, 4, and 6 days respectively.

RESULTS

The results showed that ZXHA-TC has a stimulating effect on the proliferation and osteogenic differentiation of primary osteoblasts by promoting cell proliferation, cell viability, and the expression of genes BSP and OCN. Productions of bone matrix and mineralization were also increased by ZXHA-TC treatment as a result of up-regulation of COL1A1 and alkaline phosphatase (ALP) at the early stage and down-regulation of both genes subsequently. A range of 6.25×10⁻³ microg/mL to 6.25×10⁻¹ microg/mL is the recommended dose for ZXHA-TC, within which 6.25×10⁻² μg/mL showed the best performance.

CONCLUSION

This study may hold promise for the development of a novel agent for the treatment of osteoporosis.