OBJECTIVE: Silicon-releasing biomaterials are widely used in the field of dentistry. However, unlike bone, very little is known about the role of silicon on dental tissue formation and repair. This study investigates the influence of silicic acid on the survival, differentiation and mineralizing ability of human dental pulp stem cells (hDPSCs) in 3D pulp-like environments METHODS: Dense type I collagen hydrogels seeded with hDPSCs were cultured over 4 weeks in the presence of silicic acid at physiological (10 μM) and supraphysiological (100 μM) concentrations. Cell viability and proliferation were studied by Alamar Blue and live/dead staining. The collagen network was investigated using second harmonic generation imaging. Mineral deposition was monitored by histology and scanning electron microscopy. Gene expression of mineralization- and matrix remodeling-associated proteins was studied by qPCR.
RESULTS: Presence of silicic acid did not show any significant influence on cell survival, metabolic activity and gene expression of key mineralization-related proteins (ALP, OCN, BSP). However, it induced enhanced cell clustering and delayed expression of matrix remodeling-associated proteins (MMP13, Col I). OPN expression and mineral deposition were inhibited at 100 μM. It could be inferred that silicic acid has no direct cellular effect but rather interacts with the collagen network, leading to a modification of the cell-matrix interface.
CONCLUSIONS: Our results offer advanced insights on the possible role of silicic acid, as released by pulp capping calcium silicates biomaterials, in reparative dentine formation. More globally, these results interrogate the possible role of Si in pulp pathophysiology.

UNASSIGNED: Cytotoxicity and adaptability are among the highly imperative tests that should be performed on a novel endodontic material to ensure its successful implementation in endodontic treatment.
UNASSIGNED: Assess a recently introduced bioceramic root canal sealer CeramoSeal with TotalFill BC and AH plus sealers regarding the cytotoxicity and adaptability.
UNASSIGNED: Five sealer discs were prepared for each sealer and their extracts were cultured in 96-well plates containing human fibroblasts for 24 h. After their incubation, MTT solution was added to each well plate using an enzyme-linked immunosorbent assay plate reader was implemented to calculate the percentage of viable cells. Thirty mandibular single-rooted premolars were prepared using the Edge Endo rotary system, teeth were divided into three groups (n = 10) based on the sealer type: Group 1 CeramoSeal, Group 2 Totalfill, and Group 3 AH plus sealer. Teeth were sectioned longitudinally and viewed under a scanning electron microscope where the region with the gaps was identified and quantified as a percentage of the root canal\'s overall area.
UNASSIGNED: One-way ANOVA test was used for cytotoxicity, while Kruskal-Wallis and Friedman\'s tests were used for adaptability.
UNASSIGNED: Ceramoseal statistically significantly showed the lowest viability, at high concentrations AH plus showed the highest cell viability, while at lower concentration Totalfill BC sealer showed the highest cell viability percentage. The gap percentages were statistically significantly higher in Ceramoseal group, there was no statistically significant difference between AH Plus and Totalfill groups.
UNASSIGNED: Ceramoseal sealer exhibited the lowest viability and highest gap percentage compared to the other sealers.

The aim of this work is to review the application of bioceramic materials in the context of current regenerative dentistry therapies, focusing on the latest advances in the synthesis of advanced materials using the sol-gel methodology. Chemical synthesis, processing and therapeutic possibilities are discussed in a structured way, according to the three main types of ceramic materials used in regenerative dentistry: bioactive glasses and glass ceramics, calcium phosphates and calcium silicates. The morphology and chemical composition of these bioceramics play a crucial role in their biological properties and effectiveness in dental therapeutics. The goal is to understand their chemical, surface, mechanical and biological properties better and develop strategies to control their pore structure, shape, size and compositions. Over the past decades, bioceramic materials have provided excellent results in a wide variety of clinical applications related to hard tissue repair and regeneration. Characteristics, such as their similarity to the chemical composition of the mineral phase of bones and teeth, as well as the possibilities offered by the advances in nanotechnology, are driving the development of new biomimetic materials that are required in regenerative dentistry. The sol-gel technique is a method for producing synthetic bioceramics with high purity and homogeneity at the molecular scale and to control the surfaces, interfaces and porosity at the nanometric scale. The intrinsic nanoporosity of materials produced by the sol-gel technique correlates with the high specific surface area, reactivity and bioactivity of advanced bioceramics.

This paper presents the results of a study on the evaluation of resistance of pastes from carbonated, low-lime calcium silica cements to external sulfate attack. The extent of chemical interaction between sulfate solutions and paste powders was assessed by quantifying the amount of species that leached out from carbonated pastes using ICP-OES and IC techniques. In addition, the loss of carbonates from the carbonated pastes exposed to sulfate solutions and the corresponding amounts of gypsum formed were also monitored by using the TGA and QXRD techniques. The changes in the structure of silica gels were evaluated using FTIR analysis. The results of this study revealed that the level of resistance of carbonated, low-lime calcium silicates to external sulfate attack was affected by the degree of crystallinity of calcium carbonate, the type of calcium silicate, and the type of cation present in the sulfate solution.

BACKGROUND: Recently several calcium silicate flowable sealers have been introduced as endodontic materials for the root canal. This clinical study tested the use of a new premixed calcium silicate bioceramic sealer in association with the Thermafil warm carrier-based technique (TF). Epoxy-resin-based sealer with the warm carrier-based technique was the control group.
METHODS: Healthy consecutive patients (n = 85) requiring 94 root canal treatments were enrolled in this study and assigned to one filling group (Ceraseal-TF n = 47, AH Plus-TF n = 47) in accordance with operator training and best clinical practice. Periapical X-rays were taken preoperatively, after root canal filling and after 6, 12 and 24 months. Two evaluators blindly assessed the periapical index (PAI) and sealer extrusion in the groups (k = 0.90). Healing rate and survival rate were also evaluated. Chi-square tests was used to analyze significant differences between the groups. Multilevel analysis was performed to evaluate the factors associated with healing status.
RESULTS: A total of 89 root canal treatments in 82 patients were analyzed at the end-line (24 months). The total drop-out was 3.6% (3 patients; 5 teeth). A total of 91.1% of healed teeth (PAI 1-2) was observed in Ceraseal-TF, with 88.6% in AH Plus-TF. No significant difference was observed on healing outcome and survival among the two filling groups (p > 0.05). Apical extrusion of the sealers occurred in 17 cases (19.0%). Of these, 6 occurred in Ceraseal-TF (13.3%) and 11 in AH Plus-TF (25.0%). Three Ceraseal extrusions were radiographically undetectable after 24 months. All the AH Plus extrusions did not change during the evaluation time.
CONCLUSIONS: The combined use of the carrier-based technique and premixed CaSi-based bioceramic sealer showed clinical results comparable with carrier-based technique and epoxy-resin-based sealer. The radiographical disappearance of apically extruded Ceraseal is a possible event in the first 24 months.

The aim of the study was to analyze the chemical−physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root canal sealers containing varied amounts of different calcium silicates (CaSi): a dicalcium and tricalcium silicate (1−10% and 20−30%)-containing sealer with zirconium dioxide and tricalcium aluminate (CERASEAL); a tricalcium silicate (5−15%)-containing sealer with zirconium dioxide, dimethyl sulfoxide and lithium carbonate (AH PLUS BIOCERAMIC) and a dicalcium and tricalcium silicate (10% and 25%)-containing sealer with calcium aluminate, tricalcium aluminate and tantalite (NEOSEALER FLO). An epoxy resin-based sealer (AH PLUS) was used as control. The initial and final setting times, radiopacity, flowability, film thickness, open pore volume, water absorption, solubility, calcium release and alkalizing activity were tested. The nucleation of calcium phosphates and/or apatite after 28 days aging in Hanks balanced salt solution (HBSS) was evaluated by ESEM-EDX, vibrational IR and micro-Raman spectroscopy. The analyses showed for NeoSealer Flo and AH Plus the longest final setting times (1344 ± 60 and 1300 ± 60 min, respectively), while shorter times for AH Plus Bioceramic and Ceraseal (660 ± 60 and 720 ± 60 min, respectively). Radiopacity, flowability and film thickness complied with ISO 6876/12 for all tested materials. A significantly higher open pore volume was observed for NeoSealer Flo, AH Plus Bioceramic and Ceraseal when compared to AH Plus (p < 0.05), significantly higher values were observed for NeoSealer Flo and AH Plus Bioceramic (p < 0.05). Ceraseal and AH Plus revealed the lowest solubility. All CaSi-containing sealers released calcium and alkalized the soaking water. After 28 days immersion in HBSS, ESEM-EDX analyses revealed the formation of a mineral layer that covered the surface of all bioceramic sealers, with a lower detection of radiopacifiers (Zirconium for Ceraseal and AH Plus Bioceramic, Tantalum for NeoSealer Flo) and an increase in calcium, phosphorous and carbon. The calcium phosphate (CaP) layer was more evident on NeoSealer Flo and AH Plus Bioceramic. IR and micro-Raman revealed the formation of calcium carbonate on the surface of all set materials. A thin layer of a CaP phase was detected only on AH Plus Bioceramic and NeoSealer Flo. Ceraseal did not show CaP deposit despite its highest calcium release among all the tested CaSi-containing sealers. In conclusion, CaSi-containing sealers met the required chemical and physical standards and released biologically relevant ions. Slight/limited apatite nucleation was observed in relation to the high carbonation processes.

Investigating CO2 sequestration in cement-based materials is significant for achieving carbon neutrality in the cement and concrete industries. The early CO2 sequestration pathways on cement-based materials are fundamental for CO2 sequestration, which is not clear. Towards this, the adsorption behavior of CO2 on β-C2S(100) and M3-C3S(001) was investigated at the atomic level using density functional theory calculations, which were then compared with water adsorption results. The molecular adsorption configurations of CO2 on both β-C2S(100) and M3-C3S(001) were tilted from their initial configurations due to the influence of surface Ca and O atoms. The CO2 adsorption energy on M3-C3S(001) and β-C2S(100) were -0.458 eV and -0.426 eV, respectively, indicating adsorption on M3-C3S(001) was more energetically favorable. After CO2 adsorption, electrons were transferred from the surface to the CO2 molecule. Furthermore, the Ca-O bond orders of β-C2S(100) and M3-C3S(001) after CO2 adsorption were maximally decreased by 2.79% and 6.99%, respectively. A more significant adsorption influence on surfaces was found for H2O, with more negative adsorption energy, more evident electron transfer, and a greater decrease in bond order. The CO2 adsorption on β-C2S(100) and M3-C3S(001) were still spontaneous at 298 K and 1 atm. This study provides important theoretical insights into early CO2 sequestration at the atomic level, which has practical implications for the design of efficient CO2 sequestration technologies.

The sol-gel process is a wet chemical technique that allows very fine control of the composition, microstructure, and final textural properties of materials, and has great potential for the synthesis of endodontic cements with improved properties. In this work, the influence of different sol-gel synthesis variables on the preparation of endodontic cement based on calcium silicate with Ca/Si stoichiometry equal to 3 was studied. Starting from the most optimal hydraulic composition selected, a novel second post-synthesis treatment using ethanol was essayed. The effects of the tested variables were analyzed by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen physisorption, and Gillmore needles to determine the setting time and simulated body fluid (SBF) immersion to measure the bioactive response in vitro. The results indicated that the sol-gel technique is effective in obtaining bioactive endodontic cements (BECs) with high content of the hydraulic compound tricalcium silicate (C3S) in its triclinic polymorph. The implementation of a novel post-synthesis treatment at room temperature using ethanol allows obtaining a final BEC product with a finer particle size and a higher CaCO3 content, which results in an improved material in terms of setting time and bioactive response.

The objective of this study was to evaluate the biological effects and odonto/osteogenic differentiation potential of Biodentine, NeoMTA Plus and TheraCal LC in tooth germ-derived stem cells (TGSCs). TGSCs were exposed to the material extracts. Biocompatibility was tested with MTS cell proliferation assay. Odonto/osteogenic differentiation was assessed with alkaline phosphatase (ALP) activity and mRNA gene expressions (RUNX2, DSPP and DMP-1). Scanning electronic microscopy/energy-dispersive X-ray (SEM/EDX) analysis and pH analysis were also performed for the materials. Data were evaluated using the one-way ANOVA and Tukey\'s tests. TGSCs remained viable after 7 days of incubation with all tested materials. Biodentine and NeoMTA Plus showed high ALP activity and increased expression of RUNX2, DSPP and DMP-1 compared to that of TheraCal LC. All materials can induce odonto/osteogenic differentiation of MSCs in various levels. Biocompatibility and odonto/osteogenic differentiation potential of Biodentine and NeoMTA Plus are similar and superior to that of TheraCal LC.

The effects of a new material based on hydroxyapatite and calcium silicates, named ALBO-MPCA, were investigated on the liver, kidney and spleen. The material was administrated orally for 120 days in an in vivo model in Wistar rats, and untreated animals served as a control. Hematological and biochemical blood parameters were analyzed. Qualitative histological analysis of tissues, change in mitotic activity of cells, and histological characteristics was conducted, as well as quantitative stereological analysis of parenchymal cells, blood sinusoids, and connective tissues. Additionally, the protein expressions of Ki67 and CD68 markers were evaluated. Histological analysis revealed no pathological changes after the tested period. It showed the preservation of the architecture of blood sinusoids and epithelial cells and the presence of mitosis. Additionally, the significantly increased number of the Ki67 in the presence of ALBO-MPCA confirmed the proliferative effect of the material noticed by stereological analysis, while immunoreactive CD68 positive cells did not differ between groups. The study showed non-toxicity of the tested material based on the effects on the hematological, biochemical, and observed histological parameters; in addition, it showed evidence of its biocompatibility. These results could be the basis for further steps toward the application of tested materials in endodontics.