New Portland cement-based materials for endodontics mixed with articaine solution: a study of cellular response

Osteoinductive and regenerative potential of premixed calcium-silicate bioceramic sealers on vascular wall mesenchymal stem cells

AIM

The osteogenic potential of new premixed calcium-silicate-containing bioceramic sealers (Ca-Si sealers) was tested with porcine vascular wall-mesenchymal stem cells (pVW-MSCs).

METHODOLOGY

Two Ca-Si-containing sealers: Ceraseal (MetaBiomed, Cheong-si, South Korea) and AH Plus Bioceramic (Maruchi, Wonju-si, South Korea), and an epoxy resin sealer (AH Plus; Dentsply, Konstanz, Germany) as a control, were prepared according to the manufacturers' indications. All samples were allowed to set for 100% of their setting time in a sterile humid cabinet at 37°C and 95% relative humidity. pVW-MSC seeding efficiency and osteogenic differentiation were analysed as marker of gene/protein expression for up to 12 days. Mineralization assay and immunofluorescence staining were performed and evaluated over a period of 21 days. Statistical analyses were conducted using one-way analysis of variance (p < .05). Additional samples were prepared and stored under the same conditions and inspected using an environmental scanning electron microscope equipped with an energy dispersive X-ray spectroscopy system.

RESULTS

Significantly higher cell seeding efficiency (p < .05) was observed for both Ca-Si sealers from day 8. pVW-MSCs showed a significant shift towards the osteogenic lineage only when seeded in contact with Ca-Si sealers. Gene expression of osteopontin was upregulated significantly. Collagen I and osteocalcin were clearly expressed by cells in contact with Ca-Si sealers. Mineralization granules were observed in Alizarin red assays and confocal laser scanning microscopy analysis of both Ca-Si sealers. No gene expression or granule mineralization were observed on the epoxy resin sealer.

CONCLUSIONS

Premixed Ca-Si sealers displayed a higher potential for osteogenic activity on pVW-MSCs. Epoxy resin sealer was unable to induce any osteogenic activity. The properties of both Ca-Si sealers suggest their potential as osteoinductive platforms for vascular MSCs in periapical bone.

Antibacterial and osteoinductive properties of wollastonite scaffolds impregnated with propolis produced by additive manufacturing

Biocompatible ceramic scaffolds offer a promising approach to address the challenges in bone reconstruction. Wollastonite, well-known for its exceptional biocompatibility, has attracted significant attention in orthopedics and craniofacial fields. However, the antimicrobial properties of wollastonite have contradictory findings, necessitating further research to enhance its antibacterial characteristics. This study aimed to explore a new approach to improve in vitro biological response in terms of antimicrobial activity and cell proliferation by taking advantage of additive manufacturing for the development of scaffolds with complex geometries by 3D printing using propolis-modified wollastonite. The scaffolds were designed with a TPMS (Triply Periodic Minimal Surface) gyroid geometric shape and 3D printed prior to impregnation with propolis extract. The paste formulation was characterized by rheometric measurements, and the presence of propolis was confirmed by FTIR spectroscopy. The scaffolds were comprehensively assessed for their mechanical strength. The biological characterization involved evaluating the antimicrobial effects against Staphylococcus aureus and Staphylococcus epidermidis, employing Minimum Inhibitory Concentration (MIC), Zone of Inhibition (ZOI), and biofilm formation assays. Additionally, SaOs-2 cultures were used to study cell proliferation (Alamar blue assay), and potential osteogenic was tested (von Kossa, Alizarin Red, and ALP stainings) at different time points. Propolis impregnation did not compromise the mechanical properties of the scaffolds, which exhibited values comparable to human trabecular bone. Propolis incorporation conferred antibacterial activity against both Staphylococcus aureus and Staphylococcus epidermidis. The implementation of TPMS gyroid geometry in the scaffold design demonstrated favorable cell proliferation with increased metabolic activity and osteogenic potential after 21 days of cell cultures.

The Effects of Tricalcium-Silicate-Nanoparticle-Containing Cement: In Vitro and In Vivo Studies

A tricalcium-silicate-nanoparticle-containing cement (Biodentine) was developed to overcome the disadvantages of existing mineral trioxide aggregate (MTA) dental materials. This study aimed at evaluating the effects of Biodentine on the osteogenic differentiation of human periodontal ligament fibroblasts (HPLFs) in vitro and the healing of furcal perforations created experimentally in rat molars in vivo, in comparison to MTA. The in vitro studies performed the following assays: pH measurement using a pH meter, the release of calcium ions using a calcium assay kit, cell attachment and morphology using SEM, cell proliferation using a coulter counter, marker expression using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and cell mineralized deposit formation using Alizarin Red S (ARS) staining. In the in vivo studies, MTA and Biodentine were used to fill the rat molar perforations. Rat molars were processed at 7, 14 and 28 days for analysis of inflammatory processes using hematoxylin and eosin (HE) staining, immunohistochemical staining of Runx2 and tartrate-resistant acid phosphate (TRAP) staining. The results demonstrate that the nanoparticle size distribution of Biodentine is critical for osteogenic potential at an earlier stage compared to MTA. Further studies are required to elucidate the mechanism of action of Biodentine in osteogenic differentiation.

Antibacterial activity, cytocompatibility and effect of Bio-C Temp bioceramic intracanal medicament on osteoblast biology

AIM

To analyse the antimicrobial and biological properties of a new bioceramic intracanal medicament (Bio-C Temp), and to compare it with two calcium hydroxide-based intracanal medicaments (Calen^® and UltraCal^® XS).

METHODOLOGY

The direct contact and the crystal violet tests were performed to assess the antimicrobial activity of intracanal medicaments against Enterococcus faecalis. The cytocompatibility and the effect of the medication on the biology of the human osteoblast-like cell line (Saos-2) were evaluated with methylthiazole tetrazolium (MTT), neutral red, alkaline phosphatase activity and mineralization (alizarin red) assays. The data were analysed using one-way anova and Tukey's tests, two-way anova and Bonferroni's tests, or Kruskal-Wallis and Dunn's tests (α = 0.05).

RESULTS

Bio-C Temp had significantly less antibacterial activity and biofilm biomass reduction than the other intracanal medicaments (P < 0.05). There was no difference in the viability of Saos-2 exposed to the various intracanal medicaments, except regarding the 1 : 2 dilution, when the Bio-C Temp group had significantly lower cell viability than the UltraCal^® XS and Calen^® groups (P < 0.05). Bio-C Temp induced significantly greater ALP activity than the other intracanal medicaments (P < 0.05) at day 1. Calen^® induced significantly greater deposition of mineralized nodules than the other intracanal medicaments (P < 0.05), and no difference was observed between Bio-C Temp and UltraCal^® XS (P > 0.05).

CONCLUSIONS

Bio-C Temp had similar cytocompatibility at higher dilutions, and higher or similar induction of ALP activity and deposition of mineralized nodules in comparison with Calen® and UltraCal® XS. However, it had significantly less antibacterial and antibiofilm activity than Calen® and UltraCal® XS.

Development and properties of endodontic resin sealers with natural oils

OBJECTIVES

To synthesize and evaluate the physicochemical, antimicrobial, and cytocompatibility properties of experimental resin-based endodontic sealers containing butia or copaiba natural oils.

METHODS

Experimental groups contained butia (Butia capitata) at 0.5 % (B0.5), 1 % (B1), 2 % (B2), and copaiba (Copaifera spp.) at 0.5 % (C0.5), 1 % (C1), and 2 % (C2). The control group contained no added oils (experimental material, EM) and the commercial group was a methacrylate-based resin material (RealSeal™, SybronEndo Corporation, Orange, CA, USA). Degree of conversion, film thickness, setting time, flow, water sorption and solubility, and radiopacity were measured. Meanwhile, antimicrobial (modified direct contact test) and cytotoxicity assays of the experimental groups and controls were performed. One-way ANOVA was used to determine the effect of the independent variable (material) on the degree of conversion, film thickness, radiopacity, flow, setting time, water sorption and solubility, and cytotoxicity. For antimicrobial assays, data were analyzed using two-way ANOVA and Ŝidák's test.

RESULTS

The experimental groups containing natural oils showed higher values of degree of conversion, and lowest water sorption and solubility. EM, B0.5, B1, B2, and RS showed similar film thicknesses. The flow values were statistically similar in all groups. The experimental groups showed adequate cell compatibility. Copaiba oil at 2% increased the antimicrobial effect after 1 and 24 h (p < 0.05). The incorporation of butia or copaiba resulted in a slight modification in some physicochemical properties of the experimental resin sealers.

CONCLUSION

Novel resin sealers containing natural oils are a promising alternative for endodontics, because of their good physicochemical properties, antimicrobial effects, and cytocompatibility when compared to a commercially available sealer.

CLINICAL SIGNIFICANCE

Endodontic sealers containing butia or copaiba had satisfactory cytocompatibility, antimicrobial effects, and adequate physicochemical properties.

Biocompatibility evaluation of Jordanian Portland cement for potential future dental application

Background

The demand for novel Portland cement (PC)-based formulations to be used in dental applications is ever increasing in viewing the foregoing knowledge on the favorable effects of these formulations on cellular proliferation and healing, leading to treatment success.

Aim

This study investigated the effect of white and gray mineral trioxide aggregate (W-MTA and G-MTA) and white and gray Jordanian PC (W-PC and G-PC) in their raw state on the viability of Balb/C 3T3 fibroblasts using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Materials and Methods

Materials were prepared in the form of disks, with a diameter of 5 mm and a thickness of 2 mm. In the first experiment, Balb/C 3T3 fibroblasts were cultured with the material disks using culture plate inserts. In the second experiment, material elutes were added to cultured cells. The elutes were prepared by adding 2 ml serum-free media to 10 disks of each material and then incubated at 37°C for different time intervals. Material elutes were analyzed using ion chromatography for traces of calcium. The data were analyzed using analysis of variance followed by Dunnett test (α = 0.05) or Tukey test (α = 0.05).

Results

In response to material disks, G-PC had a proliferative effect on cells at day 1 and day 2 with a significant difference from the control at day 1. G-MTA reduced cell viability with a significant difference from the control level at day 2. Elutes of PC showed biocompatible and even proliferative effects on Balb/C 3T3 fibroblasts. Calcium ions were found to leach continuously over the measurement period for all the materials tested in this work.

Conclusion

Jordanian PC in its raw state was found to be biocompatible, and the results of this work give promise of its wider use as a base for further development to improve the physiochemical and mechanical properties of the material.

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 analysis and biological properties of two different formulations of white portland cements

White Portland cement (WPC) has generated research interests in the field of endodontics. This study compared between the properties of two formulations of white Portland cement (WPC) of different origin (Malaysia [MA] and Egypt [EG]). WPCs with and without calcium chloride dihydrate were prepared. Scanning electron microscope (SEM), energy dispersive X-ray micro-analysis, and X-ray diffraction were used for surface morphology evaluation, elemental, and phase analysis, respectively. After the preparation of optimized serial dilutions, the cytotoxicity was evaluated on human periodontal ligament fibroblasts (HPLFs) and dental pulp stem cells (DPSCs) using methyl-thiazol-diphenyltetrazolium assay after 24 and 72 h. Cell attachment properties were examined under SEM after 24 and 72 h. Results showed that the surface morphology and chemical composition of both formulations demonstrated detectable variations. The cytotoxicity evaluation showed different cellular responses of HPLFs compared to DSPCs. Both formulations favored the viability of HPLFs. However, the fast set formulations demonstrated severe cytotoxicity on DPSCs. Significant differences between EGWPC and MAWPC were identified (p < 0.05). The cell attachment properties were favorable; however, HPLFs attached and spread over the samples better than DPSCs. In conclusion, WPC of different origin may show differences in chemical and biological properties. The addition of CaCl2 ·2H2 O to WPC can affect its properties. Human cell types may react differently towards different formulations of WPCs. SCANNING 38:303-316, 2016. © 2015 Wiley Periodicals, Inc.

Comparison of the Apical Sealing Ability of Calcium Silicate-Based Sealer and Resin-Based Sealer Using the Fluid-Filtration Technique

OBJECTIVE

The aim was to evaluate the apical sealing ability of tricalcium silicate-based (MTA Fillapex®) and resin-based (AH Plus®) sealers at 24 h, 7 days and 4 weeks.

MATERIALS AND METHODS

Thirty-four extracted human upper anterior teeth were used. All the teeth were sectioned to leave the root 15 mm long, and then all the roots were instrumented using a set of ProTaper® rotary instruments. Four roots were selected randomly as controls, and the remaining 30 were randomly divided into 2 groups of 15 each: MTA Fillapex and gutta-percha (group 1) and AH Plus and gutta-percha (group 2) using a warm vertical compaction technique. The apical sealing ability of the filled root canal was measured using the fluid-filtration method with 200 mm Hg (26.67 KPa) above atmospheric pressure at 24 h, 7 days and 4 weeks. The apical microleakage of the 2 groups was compared using Student's t test. p < 0.05 was considered statistically significant.

RESULTS

The mean apical microleakage in group 1 at 24 h, 7 days and 4 weeks was 1.01 ± 0.24, 0.43 ± 0.07 and 0.24 ± 0.08 nl/s. The corresponding values in group 2 were 1.15 ± 0.40, 0.32 ± 0.09, and 0.38 ± 0.10 nl/s. MTA Fillapex had significantly more leakage than AH Plus at 7 days, but at 4 weeks, MTA Fillapex showed a significantly better sealing ability than AH Plus (p < 0.05).

CONCLUSIONS

In this study, the tricalcium silicate-based sealer promoted proper sealing when used for filling the root canals.

Radiopacity and cytotoxicity of Portland cement associated with niobium oxide micro and nanoparticles

OBJECTIVE

Mineral Trioxide Aggregate (MTA) is composed of Portland Cement (PC) and bismuth oxide (BO). Replacing BO for niobium oxide (NbO) microparticles (Nbµ) or nanoparticles (Nbη) may improve radiopacity and bioactivity. The aim of this study was to evaluate the radiopacity and cytotoxicity of the materials: (1) PC; (2) White MTA; (3) PC+30% Nbµ; (4) PC+30% Nbη.

MATERIAL AND METHODS

For the radiopacity test, specimens of the different materials were radiographed along an aluminum step-wedge. For cell culture assays, Saos-2 osteoblastic-cells (ATCC HTB-85) were used. Cell viability was evaluated through MTT assay, and bioactivity was assessed by alkaline phosphatase activity assay.

RESULTS

The results demonstrated higher radiopacity for MTA, followed by Nbµ and Nbη, which had similar values. Cell culture analysis showed that PC and PC+NbO associations promoted greater cell viability than MTA.

CONCLUSIONS

It was concluded that the combination of PC+NbO is a potential alternative for composition of MTA.

Physical properties and biocompatibility of an injectable calcium-silicate-based root canal sealer: in vitro and in vivo study

Background

The aim of this study was to investigate the physical properties and biological effects of an experimentally developed injectable premixed calcium-silicate root canal sealer (Endoseal) in comparison with mineral trioxide aggregate (MTA) and a resin-based sealer (AHplus).

Methods

The pH, solubility, dimensional change, flow, and radiopacity of the materials were evaluated. Biocompatibility was evaluated on the basis of cell morphology and a viability test using MC3T3-E1 cells. For evaluate inflammatory reaction, the tested sealers were implanted into dorsal subcutaneous connective tissue of Sprague Dawley rats. After 7 days, the implants with the surrounding tissue were retrieved, and histological evaluation was performed.

Results

Endoseal showed high alkalinity similar to that of MTA. The solubility of the tested materials was similar. The dimensional change and flow of Endoseal was significantly higher than that of other materials (P < 0.05). The radiopacity of Endoseal was lower than that of AHplus (P < 0.05). The biocompatibility was similar to those of MTA. Inflammatory reaction of Endoseal was similar with that of MTA, but lower than that of AHplus (P < 0.05).

Conclusions

The present study indicates that Endoseal has favorable physical properties and biocompatibility. Therefore, we suggest that Endoseal has the potential to be used as a predictable root canal sealer.

Comparative evaluation of the calcium release from mineral trioxide aggregate and its mixture with glass ionomer cement in different proportions and time intervals - An in vitro study

Background

Addition of glass ionomer cement (GIC) has been suggested to improve the setting time and handling characteristics of mineral trioxide aggregate (MTA). This study evaluated the effect of adding GIC to MTA in terms of calcium release, an issue that has not been previously studied.

Materials and methods

The study comprised four groups with five samples each: a control group of MTA alone and experimental groups I (1MTA:1GIC), II (2MTA:1GIC), and III (1MTA:2GIC) based on the mixture of MTA and GIC powders in the respective proportions by volume. Calcium release from the samples was measured by atomic absorption spectrophotometry at 15 min, 6 h, 24 h, and 1 week after setting. The level of statistical significance was set at p < 0.05.

Results

Groups I (1MTA:1GIC) and III (1MTA:2GIC) released significantly less calcium than the control group at all time periods, except at 15 min for group I. Group II (2MTA:1GIC) showed no significant difference in calcium release compared to the control at any time period. Group II exhibited greater calcium release than group I or III at all time periods, with significant differences between groups I and II at 1 week and between groups I and III at 24 h and 1 week. There were no statistical differences in calcium release between groups I and III.

Conclusions

Adding GIC to improve the setting time and handling properties of the MTA powder can be detrimental to the calcium-releasing ability of the resultant mixture, depending on the proportion of GIC added. Adding MTA and GIC at a proportion of 2:1 by volume did not impact calcium release from the mixture. These findings should be verified through further clinical studies.

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

AIM

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

(α'(H))-Dicalcium silicate bone cement doped with tricalcium phosphate: characterization, bioactivity and biocompatibility

The influence of phosphorus doping on the properties of (α'(H))-dicalcium silicate (C(2)S) bone cement was analyzed, in addition to bioactivity and biocompatibility. All the cements were composed of a solid solution of TCP in C(2)S ([Formula: see text]-C(2)S(ss)) as the only phase present. The compressive strength ranged from 3.8-16.3 MPa. Final setting times ranged from 10 to 50 min and were lower for cements with lower L/P content. Calcium silicate hydrate was the principal phase formed during the hydration process of the cements. The cement exhibited a moderate degradation and could induce carbonated hydroxyapatite formation on its surface and into the pores. The cell attachment test showed that the (α'(H))-C(2)SiO(4) solid solution supported human adipose stem cells adhesion and spreading, and the cells established close contacts with the cement after 24 h of culture. The novel (α'(H))-C(2)S(ss) cements might be suitable for potential applications in the biomedical field, preferentially as materials for bone/dental repair.

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

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

In vitro fracture resistance of roots obturated with epoxy resin-based, mineral trioxide aggregate-based, and bioceramic root canal sealers

INTRODUCTION

The aim of this study was to evaluate the fracture resistance of teeth filled with 3 different endodontic sealers.

METHODS

Seventy-five single-rooted extracted mandibular premolars were decoronated to a length of 13 mm. The teeth were randomly divided into 5 groups (n = 15 for each group). In group 1, the teeth were left unprepared and unfilled (negative control), and in group 2, the teeth were left unobturated (positive control). The rest of the roots were prepared by using the ProTaper System up to a master apical file size of F3: group 3, bioceramic sealer (Endosequence BC sealer) + gutta-percha; group 4, mineral trioxide aggregate-based sealer (Tech Biosealer Endo) + gutta-percha; and group 5, epoxy resin-based sealer (AH Plus Jet) + gutta-percha. All root specimens were stored for 2 weeks at 100% humidity to allow the complete setting of the sealers. Each specimen was then subjected to fracture testing by using a universal testing machine at a crosshead speed of 1.0 mm/min(-1) until the root fractured. The force required to fracture each specimen was recorded, and the data were analyzed statistically.

RESULTS

The fracture values of groups 3 and 5 were significantly higher than those of group 4 (P < .05). There was no significant difference between groups 3 and 5 (P > .05).

CONCLUSIONS

In contrast to Tech Biosealer Endo, Endosequence BC and AH Plus Jet sealer increased the force to fracture in root-filled single-rooted premolar teeth.

Mineral trioxide aggregate-based endodontic sealer stimulates hydroxyapatite nucleation in human osteoblast-like cell culture

INTRODUCTION

The main purpose of this study was to evaluate the biocompatibility and bioactivity of a new mineral trioxide aggregate (MTA)-based endodontic sealer, MTA Fillapex (MTA-F; Angelus, Londrina, Brazil), in human cell culture.

METHODS

Human osteoblast-like cells (Saos-2) were exposed for 1, 2, 3, and 7 days to MTA-F, Epiphany SE (EP-SE; SybronEndo, Orange, CA), and zinc oxide-eugenol sealer (ZOE). Unexposed cultures were the control group (CT). The viability of the cells was assessed by MTT assay and the morphology by scanning electron microscopy (SEM). The bioactivity of MTA-F was evaluated by alkaline phosphatase activity (ALP) and the detection of calcium deposits in the culture with alizarin red stain (ARS). Energy-dispersive X-ray spectroscopy (EDS) was used to chemically characterize the hydroxyapatite crystallites (HAP). Saos-2 cells were cultured for 21 days for ARS and SEM/EDS. ARS results were expressed as the number of stained nodules per area. Statistical analysis was performed with analysis of variance and Bonferroni tests (P < .01).

RESULTS

MTA-F exposure for 1, 2, and 3 days resulted in increased cytotoxicity. In contrast, viability increased after 7 days of exposure to MTA-F. Exposure to EP-SE and ZOE was cytotoxic at all time points. At day 7, ALP activity increase was significant in the MTA-F group. MTA-F presented the highest percentage of ARS-stained nodules (MTA-F > CT > EP-SE > ZOE). SEM/EDS analysis showed hydroxyapatite crystals only in the MTA-F and CT groups. In the MTA-F group, crystallite morphology and chemical composition were different from CT.

CONCLUSIONS

After setting, the cytotoxicity of MTA-F decreases and the sealer presents suitable bioactivity to stimulate HAP crystal nucleation.

Biomimetic calcium-silicate cements support differentiation of human orofacial mesenchymal stem cells

INTRODUCTION

Human orofacial bone mesenchymal stem cells (OFMSCs) from maxilla and mandible have robust osteogenic regenerative properties on the basis of our previous reports that demonstrate phenotypic and functional differences between jaw and axial bone mesenchymal stem cells in same individuals. Furthermore, a combination of OFMSCs with bioactive calcium-releasing cements can potentially improve OFMSC multilineage differentiation capacity, but biocompatibility of calcium-silicate cements with OFMSCs is still unclear. We tested the hypothesis that material extracts of calcium-releasing calcium-silicate cements support biomimetic microenvironment for survival and differentiation of human OFMSCs.

METHODS

Two experimental calcium-silicate cements, (1) calcium-silicate mineral powder (wTC) containing dicalcium and tricalcium-silicate, calcium sulfate, and calcium chloride and (2) wTC doped with alpha-tricalcium phosphate (wTC-αTCP), were designed and prepared. Cement setting times were assessed by Gilmore needles, ability to release calcium and hydroxyl ions was assessed by potentiometric methods, and OFMSC attachment to calcium-silicate discs was assessed. Calcium-silicate material extracts were tested for ability to support OFMSC survival and in vitro/in vivo differentiation.

RESULTS

Fewer OFMSCs attached to calcium-silicate discs relative to tissue culture plastic (P = .001). Extracts of calcium-silicate cements sustained OFMSC survival, maintained steady state levels of vascular cell adhesion molecule-1, alkaline phosphatase, and bone sialoprotein while up-regulating their respective gene transcripts. Adipogenic and in vivo bone regenerative capacities of OFMSCs were also unaffected by calcium-silicate extracts.

CONCLUSIONS

Ion-releasing calcium-silicate cements support a biomimetic microenvironment conducive to survival and differentiation of OFMSCs. Combination of OFMSCs and calcium-silicate cement can potentially promote tissue regeneration in periapical bone defects.

Comparative study of subcutaneous tissue responses to a novel root-end filling material and white and grey mineral trioxide aggregate

AIM

To compare the subcutaneous tissue response to grey mineral trioxide aggregate (GMTA), white mineral trioxide aggregate (WMTA) and a new experimental cement (calcium enriched cement, CEM).

METHODOLOGY

Thirty-six Wistar male albino rats each received three implants, containing one of the tested materials, and an empty tube as a control. Seven, 30 and 60 days after implantation, the animals were sacrificed. After histological preparation and H&E staining, the specimens were evaluated for capsule thickness, necrosis, and for the type, the severity, and the extent of inflammation. Kruskal Wallis and Chi-square tests were used for data analysis.

RESULTS

After 1 week, CEM produced no necrosis compared to both types of WMTA and GMTA (P = 0.007). After 30 days, GMTA specimens had significantly less inflammation compared with WMTA and CEM (P = 0.011). After 60 days, less inflammation was associated with CEM specimens (P = 0.0001) compared to the other materials. Dystrophic calcifications in the connective tissue adjacent to all experimental material were detected.

CONCLUSION

Histological observation illustrated that all materials were well tolerated by the subcutaneous tissues.

MTA and F-doped MTA cements used as sealers with warm gutta-percha. Long-term study of sealing ability

AIM

To evaluate the long-term sealing ability (up to 6 months) of two experimental calcium silicate MTA cements used as root canal sealers in association with warm gutta-percha.

METHODOLOGY

Calcium silicate (MTA) and calcium-fluoro-silicate powders were prepared. Sodium fluoride was included in FMTA (Fluoride-doped Mineral Trioxide Aggregate) as an expansive and retardant agent. Single-rooted teeth were instrumented with NiTi rotary instruments, filled with warm gutta-percha in association with one of the experimental sealers or with AH Plus as a control (n = 20 for each sealer) and stored at 37 °C. Sealing was assessed at 24, 48 h, 1, 2 weeks and 1, 3, 6 months by a fluid filtration method. Scanning electron microscopy with energy dispersive analysis (SEM/EDX) was used to study the dentine/sealer interface of roots stored for 6 months and the surface of cement disks stored for 24 h.

RESULTS

All sealers revealed a statistically significant reduction (P < 0.05) in fluid filtration after the first 2 weeks. No statistically significant differences were observed between FMTA and AH Plus at all analysis times. At short times (24, 48-h), no statistically significant differences were found between the experimental cements and AH Plus. At long-term evaluations (1, 3, 6 months), FMTA and AH Plus sealed significantly better (P < 0.05) than MTA. FMTA was associated with lower fluid filtration rates, and the seal was stable from 48 h to 6 months, thus proving the most effective material. Scanning electron microscopy with energy dispersive analysis of root sections filled with calcium silicate sealers revealed the formation of a blend layer of gutta-percha and cement consequent to the warm gutta-percha condensation technique. Scanning electron microscopy with energy dispersive analysis of 24-h-stored disks identified a Ca-rich coating on the outer surface consisting of globular particles (calcium hydroxide and calcium carbonate), and a deeper internal Ca- and Si-rich region consisting of needle-like ettringite crystals and round formations of calcium silicate hydrate gel.

CONCLUSION

Fluoride-doped MTA demonstrated stable sealing during a period of up to 6 months and significantly better than conventional calcium silicate MTA cements and comparable to AH Plus. The study supports the suitability of calcium silicate MTA cements as sealers in association with warm gutta-percha for root filling.

Environmental scanning electron microscopy connected with energy dispersive x-ray analysis and Raman techniques to study ProRoot mineral trioxide aggregate and calcium silicate cements in wet conditions and in real time

INTRODUCTION

ProRoot mineral trioxide aggregate (MTA) and calcium silicate cements are able to set in a moist environment. The aim of the study was to examine the surface structure and composition of a cement paste under wet conditions and in real time during setting by environmental scanning electron microscopy connected with energy dispersive x-ray analysis (ESEM-EDX) and micro-Raman techniques.

METHODS

White ProRoot MTA and experimental white tetrasilicate cement (wTC) and wTC containing bismuth oxide (wTC-Bi) were studied. Cement disks were analyzed 10 minutes after powder-liquid mixing (freshly prepared samples) and after immersion in Dulbecco phosphate-buffered saline at 37 degrees C for 24 hours (24-hour-aged samples).

RESULTS

Freshly prepared wet cements at ESEM-EDX exposed an irregular surface (displaying calcium, silicon, aluminum, chlorine reflexes, and bismuth traces in MTA and wTC-Bi) with needle-like and cubic-hexagonal shaped crystals. Aggregates of spheroidal Ca-P-rich crystals (spherulites) appeared on the surface of 24-hour-aged samples. The starting unhydrated powders displayed the typical Raman bands of Portland cement components: alite, belite, and calcium sulfate (only as anhydrite in MTA and as both anhydrite and gypsum in wTC and wTC-Bi). MTA powder showed higher amount of calcium carbonate and lower quantities of anhydrite and higher crystallinity of the silicate component, leading to a slower hydration reaction. Products/markers of hydration reactions were present on fresh samples; ettringite formed on the surface of all the cements; calcium hydroxide (portlandite) was detected only on the surface of wTC, but no conclusion can be drawn on wTC-Bi and MTA because of the interference of bismuth oxide. Calcium phosphate and calcite/aragonite bands were detected on all 24-hour-aged cements; portlandite was no longer detected on wTC.

CONCLUSIONS

ESEM and micro-Raman are powerful and suitable techniques to investigate endodontic calcium silicate hydrated cements in real time and in their humid state without inducing artifacts by sample preparation. The formation of apatite spherulites on calcium silicate cements might have clinical relevance.

Reparative dentinogenesis induced by mineral trioxide aggregate: a review from the biological and physicochemical points of view

This paper aims to review the biological and physicochemical properties of mineral trioxide aggregate (MTA) with respect to its ability to induce reparative dentinogenesis, which involves complex cellular and molecular events leading to hard-tissue repair by newly differentiated odontoblast-like cells. Compared with that of calcium hydroxide-based materials, MTA is more efficient at inducing reparative dentinogenesis in vivo. The available literature suggests that the action of MTA is attributable to the natural wound healing process of exposed pulps, although MTA can stimulate hard-tissue-forming cells to induce matrix formation and mineralization in vitro. Physicochemical analyses have revealed that MTA not only acts as a "calcium hydroxide-releasing" material, but also interacts with phosphate-containing fluids to form apatite precipitates. MTA also shows better sealing ability and structural stability, but less potent antimicrobial activity compared with that of calcium hydroxide. The clinical outcome of direct pulp capping and pulpotomy with MTA appears quite favorable, although the number of controled prospective studies is still limited. Attempts are being conducted to improve the properties of MTA by the addition of setting accelerators and the development of new calcium silicate-based materials.

Setting time and expansion in different soaking media of experimental accelerated calcium-silicate cements and ProRoot MTA

OBJECTIVES

The setting time and the expansion in deionized water, phosphate-buffered saline (PBS), 20% fetal bovine serum (FBS)/80% PBS or hexadecane oil of experimental accelerated calcium-silicate cements and ProRoot MTA were evaluated.

STUDY DESIGN

Different compounds such as sodium fluoride, strontium chloride, hydroxyapatite, and tricalcium phosphate were separately added to a basic experimental calcium-silicate cement to test their effect on setting and expansion. The initial and final setting times were determined using appropriate Gilmore needles. A linear variable differential transformer (LVDT) device was used to test the restricted hygroscopic linear expansion over 180 minutes of cements immersed in different solutions. Results were statistically compared using a 2-way ANOVA test (cement type versus solution type).

RESULTS

All experimental cements showed initial setting times between 28 and 45 minutes and final setting times between 52 and 80 minutes. MTA showed a final setting time of 170 minutes. Final setting time of all experimental cements was faster than MTA. All cements showed slight (0.04%-0.77%) expansion in water, PBS, or FBS/PBS. Only fluoride-containing cement showed a significant expansion in water (6.68%) and in PBS (6.72%). The PBS/FBS contamination significantly reduced the expansion of fluoride-containing cement (2.98%) and MTA (0.07%). In contrast, cements showed a slight shrinkage when immersed in hexadecane, especially fluoride-containing cement.

CONCLUSIONS

The study demonstrated that: (1) the setting time of calcium-silicate cements may be effectively reduced; (2) the expansion is a water dependent mechanism owing to water uptake, because no expansion occurred in cements immersed in oil; (3) a correlation between setting time and expansion in water and PBS exists; (4) fluorine-containing cement showed a significant expansion in water and in PBS; (5) the immersion in FBS/PBS strongly reduced the expansion of MTA and fluoride-doped cement suggesting that fluid contamination (ie, blood) during surgical procedures may greatly affect the expansion of some calcium-silicate cements.

Interaction of articaine hydrochloride with prokaryotic membrane lipids

OBJECTIVE

Local anesthetics are the most commonly used drugs in dentistry, with a wide range of effects, including antimicrobial activity. High antimicrobial effects have recently been reported on oral microbes from articaine hydrochloride, revealed by the minimum inhibitory concentration and minimal bactericidal concentration. Additionally, articaine has recently been used as an alkaline component in endodontic materials with a proposed antibacterial activity. However, the detailed mechanisms of action have not been discussed.

MATERIAL AND METHODS

We determined the Langmuir surface pressure/molecular area isotherms of prokaryotic lipid monolayers, as well as the phospholipid phase transitions, by employing differential scanning calorimetry on unilamellar prokaryotic liposomes (bilayers).

RESULTS

Articaine hydrochloride was found to interact with the prokaryotic membrane lipids in both monolayers and bilayers. An increase of the phospholipid molecular area of acidic glycerophospholipids as well as a decrease in phase transition temperature and enthalpy were found with increasing articaine hydrochloride concentration. The thermodynamic changes by adding articaine hydrochloride to prokaryotic membrane lipids are potentially related to the effects observed from antimicrobial peptides resulting from membrane insertion, aggregate composition, pore formation, and lysis.

CONCLUSION

Interaction of articaine hydrochloride with prokaryotic membrane lipids is indicated. Hence, further research is necessary to gain insight into where these compounds exert their effects at the molecular level.