Strontium Silicate Research Articles

Cytotoxicity and cell migration evaluation of a strontium silicate-based root canal sealer on stem cells from rat apical papilla: an in vitro study

BackgroundCalcium silicate-based bioceramics have been applied in endodontics as advantageous materials for years, many chemical components and new synthesizing methods were used to improve the base formulation of the materials for positively affecting the sealers properties. Recently, a novel biomaterial formulation, grounded in strontium silicate, has been introduced to the market, offering potential advancements in the field.ObjectiveTo comparatively analyze the cytotoxicity and cell migration effects of a novel strontium silicate-based bioceramic material (CRoot SP) and those of calcium silicate-based (iRoot SP) and epoxide amine resin (AH Plus) sealers on stem cells derived from rat apical papilla(rSCAPs).MethodsrSCAPs were isolated and characterized in vitro and subsequently cultured in the presence of various concentrations of CRoot SP, iRoot SP and AH Plus extracts. Cytotoxicity was assessed by CCK-8 assay, and cell-migration capacity was assessed by using wound healing assays .ResultsNo significant differences in cell viability were observed in the 0.02 mg/mL and 0.2 mg/mL sealer groups. The cell viability of CRoot SP was consistently greater than that of iRoot SP at concentrations of 5 mg/mL and 10 mg/mL across all time points. Maximum cytotoxic effect was noted on day 5 with 10 mg/mL AH Plus.The scratch was partly healed by cell migration in all groups at 24 h, and the 0.02 mg/mL, and 0.2 mg/mL CRoot SP exerted beneficial effects on rSCAPs migration.ConclusionsCRoot SP exhibited less cytotoxic than the iRoot SP and AH Plus extracts after setting. A lower concentration of CRoot SP thus promotes the cell migration capacity of rSCAPs, and it may achieve better tissue repair during root canal treatment.

Delineating Dy3+ and Sm3+ in thermally stable strontium silicate apatites for multifunctional applications

The structural, optical and temperature dependent luminescence properties of a series of Sr2Y8-xREx(SiO4)6O2 (RE=Dy and Sm) silicate phosphors are investigated for their multifunctional applications. The phosphors were synthesized using the solid-state reaction route with varying doping levels and characterized for phase purity. X-ray Diffraction analysis revealed the hexagonal crystal structure of (Sr2RE2)(RE6)(SiO4)6O2, indicating the incorporation of rare earth (RE) ions into two distinct crystallographic sites, thereby augmenting the luminescence properties. Dy3+ doped compounds exhibit intense yellow emission, promising white light generation when paired with InGaN blue LED chips. Sm3+ doped samples show orange-red emission around 601 nm, attributed to multipole-multipole interactions, with rapid decay curves suitable for high-speed response LEDs. Correlated Color Temperature (CCT) values were computed to assess the commercial viability of these phosphors in luminescence applications and the role of lighting in the growth of indoor plants and office spaces is discussed. The Sr2Y7.8Dy0.2(SiO4)6O2 phosphor with remarkable quantum yield of 63.56% demonstrated a thermal stability of 0.27 eV with enhanced sensitivity of about 0.39% K−1 and Sr2Y7.8Sm0.2(SiO4)6O2 with stability around 0.31eV with sensitivity of 1.11% K⁻¹ at 100K reveals them as potential candidates for optical temperature sensing. These results declare the competence of synthesized novel silicate apatites in solid-state lighting and optical thermometry.

Synthesis of a Calcium Silicate Cement Containing a Calcinated Strontium Silicate Phase.

The positive effects of strontium on dental and skeletal remineralization have been confirmed in the literature. This study aimed to assess the properties of a calcium silicate cement (CSC) containing a sintered strontium silicate phase. The calcium silicate and strontium silicate phases were synthesized by the sol-gel technique. Strontium silicate powder in 0 (CSC), 10 (CSC/10Sr), 20 (CSC/20Sr), and 30 (CSC/30Sr) weight percentages was mixed with calcium silicate powder. Calcium chloride was used in the liquid phase. X-ray diffraction (XRD) of specimens was conducted before and after hydration. The setting time and compressive strength were assessed at 1 and 7 days after setting. The set discs of the aforementioned groups were immersed in the simulated body fluid (SBF) for 1 and 7 days. The ion release profile was evaluated by inductively coupled plasma-optical emission spectrometry (ICP-OES). Biomineralization on the specimen surface was evaluated by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Data were analyzed by the Kolmogorov-Smirnov test, one-way and mixed ANOVA, Levene's test, and LSD post hoc test (P < 0.05). Except for an increasement in the peak intensity of hydrated specimens, XRD revealed no other difference in the crystalline phases of hydrated and nonhydrated specimens. The compressive strength was not significantly different at 1 and 7 days in any group (P > 0.05). The setting time significantly decreased by an increase in percentage of strontium (P < 0.05). Release of Ca and Si ions significantly decreased by an increase in percentage of strontium (P < 0.05). SEM/EDS showed the formation of calcium phosphate deposits at 1 and 7 days. Incorporation of 10-30 wt% sintered strontium silicate phase as premixed in CSC can significantly decrease the setting time without compromising the compressive strength or biomineralization process of the cement.

Enamel remineralization potential and antimicrobial effect of a fluoride varnish containing calcium strontium silicate.

ObjectivesTo investigate enamel remineralization and antimicrobial effect of sodium fluoride (NaF) varnish containing calcium strontium silicate (CSR). MethodsCSR was synthesized by sol-gel process and incorporated in 5 % NaF varnish at three different concentrations (1 %, 2 %, and 4 % w/v). The treatment/control groups were: 1 % CSR+NaF, 2 % CSR+NaF, 4 % CSR+NaF, NaF, and no treatment. Strontium and fluoride release from the varnishes was evaluated. Sound enamel specimens (n = 6) were demineralized, varnish-treated, and subjected to remineralization cycle. Mineral density of enamel specimens was evaluated using micro-CT. Antimicrobial effect of the varnishes on Streptococcus mutans and Lactobacillus acidophilus biofilms was assessed using confocal laser scanning microscopy. The HGF-1 cytotoxicity of the varnishes was examined using CCK-8 assay. ResultsBoth 2 % and 4 % CSR+NaF varnishes showed significantly higher F release and remineralization potential than NaF varnish (p < 0.05). Dead bacterial proportion of 4 % CSR+NaF varnish was significantly higher than NaF varnish (p < 0.05). The CFUs values of both S. mutans and L. acidophilus were significantly lower in 4 % CSR+NaF group than NaF group (p < 0.05). No significant difference in cell viability was observed among the groups (p > 0.05). ConclusionsIncorporation of 4 % CSR in a NaF varnish significantly enhanced its enamel remineralization and antimicrobial potential with no cytotoxic effect. Clinical significanceDental caries is a major public health problem globally. The study highlights the great potential of CSR-doped NaF varnish as a novel anti-caries agent with synergistic remineralizing and antimicrobial properties to combat early enamel caries lesions in the general population.

TL, OSL, EPR, and defect centers in Tb-doped strontium silicate phosphor synthesized by a solid-state reaction method

Strong thermoluminescence (TL) was observed in Tb-doped strontium silicate phosphor prepared by the solid-state reaction method. Two glow peaks are observed at 100 and 190 °C. TL emission spectra indicate three recombination centers. The number of peaks and the kinetic parameters associated with the TL glow peaks of Tb-doped Sr2SiO4 phosphor after gamma irradiation were analyzed by Tm-Tstop and deconvolution methods. A study of defect centers induced by γ-irradiation and identification of defect centers responsible for the observed TL glow peaks has been carried out using the electron paramagnetic resonance (EPR) technique. The observed spectrum at room temperature is a superposition of at least three defect centers. Center I is characterized by an axially symmetric g-tensor with principal values g|| = 2.019, and g⊥ = 2.0013 and is ascribed to a O2− ion. Center II has a rhombic g-tensor with principal values 2.0072, 2.0024, and 1.995 and is assigned to an F+ center (singly ionized oxygen vacancy) and correlates with the 190 °C TL peak. The third center (center III) has an isotropic g-value of 1.991 and is identified as an F+ center.

Low cost strontium silicate nanoceramics prepared in water glass medium for bone tissue repair: in vitro studies

Low cost strontium silicate nanoceramics prepared in water glass medium for bone tissue repair: in vitro studies

Correction to: Structural Characterization of Strontium Silicate Glasses and Glass Ceramics Applied as Glass Ionomer Cements (GICs)

Correction to: Structural Characterization of Strontium Silicate Glasses and Glass Ceramics Applied as Glass Ionomer Cements (GICs)

Enhancing Compressive Strength and Dentin Interaction of Mineral Trioxide Aggregate by Adding SrO and Hydroxyapatite

In this research, the effect of strontium oxide (SrO) and hydroxyapatite (HA) on the properties of mineral trioxide aggregate (MTA) have been studied. MTA contained 20% SiO2, 60% CaO, and 2% Al2O3. Bi2O3 and SrO have been added with 18% (w/w) total percentage. MTA was prepared with a sol-gel process using a weak base (NH3) as a catalyst and calcined at 1000 °C for 3 h. The effect of HA was investigated by adding various percentages (3, 6, and 9%) on the MTA modified with 5% SrO. The modified MTA (MTA-SrO-HA) products were hydrated using water with the MTA to water weight ratio of 3:1. The results showed that tricalcium silicate (C3S), dicalcium silicate (C2S), Bi2O3, and strontium silicate peaks were detected in the XRD patterns. An increase in the intensity in the infrared spectra of CaO occurred after hybridization with HA. In addition, bonding of Ca-O-Si appeared at 879 and 995 cm−1, indicating the formation of cement. MTA modified with 5% SrO and 6% HA showed similar compressive strength to the commercial MTA (ProRoot brand). Furthermore, MTA-SrO5/HA6 showed a strong interface interaction with dentin adheres without any gaps, indicating a potential dental material for the future.

Physicochemical Properties and Inductive Effect of Calcium Strontium Silicate on the Differentiation of Human Dental Pulp Stem Cells for Vital Pulp Therapies: An In Vitro Study.

The development of biomaterials that exhibit profound bioactivity and stimulate stem cell differentiation is imperative for the success and prognosis of vital pulp therapies. The objectives were to (1) synthesize calcium strontium silicate (CSR) ceramic through the sol–gel process (2) investigate its physicochemical properties, bioactivity, cytocompatibility, and its stimulatory effect on the differentiation of human dental pulp stem cells (HDPSC). Calcium silicate (CS) and calcium strontium silicate (CSR) were synthesized by the sol–gel method and characterized by x-ray diffraction (XRD). Setting time, compressive strength, and pH were measured. The in vitro apatite formation was evaluated by SEM-EDX and FTIR. The NIH/3T3 cell viability was assessed using an MTT assay. The differentiation of HDPSC was evaluated using alkaline phosphatase activity (ALP), and Alizarin red staining (ARS). Ion release of Ca, Sr, and Si was measured using inductive coupled plasma optical emission spectroscopy (ICP-OES). XRD showed the synthesis of (CaSrSiO4). The initial and final setting times were significantly shorter in CSR (5 ± 0.75 min, 29 ± 1.9 min) than in CS (8 ± 0.77 min, 31 ± 1.39 min), respectively (p < 0.05). No significant difference in compressive strength was found between CS and CSR (p > 0.05). CSR demonstrated higher apatite formation and cell viability than CS. The ALP activity was significantly higher in CSR 1.16 ± 0.12 than CS 0.92 ± 0.15 after 14 d of culture (p < 0.05). ARS showed higher mineralization in CSR than CS after 14 and 21 d culture times. CSR revealed enhanced differentiation of HDPSC, physicochemical properties, and bioactivity compared to CS.

Can strontium replace calcium in bioactive materials for dental applications?

The substitution of calcium with strontium in bioactive materials has been promising but there has been some concern over the material instability and possible toxicity. The aim of this research was the synthesis and characterization of calcium and strontium substituted bioactive materials and assessment of interactions with local tissues and peripheral elemental migration in an animal model. A bioactive glass, hydroxyapatite and hydraulic calcium silicate with 50% or 100% calcium substitution with strontium were developed and the set materials were characterized immediately after setting and after 30 and 180-days in solution. Following subcutaneous implantation, the local (tissue histology, elemental migration) and systemic effects (elemental deposition after organ digestion) were assessed. The strontium-replaced silicate cements resulted in the synthesis of partially substituted phases and strontium leaching at all-time points. The strontium silicate implanted in the animal model could not be retrieved in over half of the specimens showing the high rate of material digestion. Tissue histology showed that all materials caused inflammation after 30 days of implantation however this subsided and angiogenesis occurred after 180 days. Strontium was not detected in the local tissues or the peripheral organs while all calcium containing materials caused calcium deposition in the kidneys. The tricalcium silicate caused elemental migration of calcium and silicon in the local tissues shown by the elemental mapping but no deposition of calcium was identified in the peripheral organs verified by the assessment of the digested tissues. Strontium can substitute calcium in bioactive materials without adverse local or systemic effects.

Electronic and spectroscopic studies of rare earth doped yttrium strontium silicate fluorapatite compound

This paper reports the luminescence studies and first principle calculations based on density functional theory (DFT) using B3LYP/def2-SVP hybrid GGA function of rare earth doped yttrium strontium silicate fluorapatite (Y6-xSr4(SiO4)6F2:xEr3+) compound synthesized by solution combustion method and characterized by XRD, SEM and Raman spectroscopy. Raman spectra of synthesized compound confirms the formation of symmetric and asymmetric bending and stretching Raman active modes within SiO4 tetrahedron. Photoluminescence spectroscopy of Y6-xSr4(SiO4)6F2:xEr3+ compounds show emission spectra at 522 nm with high lumen intensity attributing to 2H11/2 – 4I15/2 electric dipole transition in the green region under 260 nm UV excitation radiation. In the thermoluminescence analysis prepared compound shows the presence of six trap levels where difference between the shallowest and deepest trap was found to be 1.396 eV, as calculated by computerised glow curve deconvolution (CGCD). The computational crystal structure shows a good agreement with experimental structural (XRD) analysis which confirms the formation of hexagonal closed packed structure along with space group P63/m. Frontier molecular orbital calculations were done and the value of ΔE = 5.05243 eV and 1.60969 eV were calculated for Y6Sr4(SiO4)6F2 and Y5ErSr4(SiO4)6F2 compounds. The Mulliken population of Er – O is more than Y – O which shows that covalency of Y5ErSr4(SiO4)6F2 is more than covalency of Y6Sr4(SiO4)6F2 compound. The electronic band structure and total density of states of Er3+ ion substituted Y6-xSr4(SiO4)6F2 shows semiconducting behaviour of compounds.

Structural Characterization of Strontium Silicate Glasses and Glass Ceramics Applied as Glass Ionomer Cements (GICs)

Structural Characterization of Strontium Silicate Glasses and Glass Ceramics Applied as Glass Ionomer Cements (GICs)

Phase separation and the properties of lithium strontium silicate glasses

The immiscibility region covers most of the region of glass formation in the lithium strontium silicate system. Although the density, refractive index, and thermal expansion coefficient are insensitive to the presence of phase separation, the glass transformation temperature can be used to determine the limit of immiscibility in this system. The dilatometric softening temperature was used to determine the boundary the limit of connectivity of the silica-rich phase. The electrical conductivity and activation energy for conduction were used to determine the limit of connectivity of the lithium-rich phase.

FABRICATION AND STRUCTURAL CHARACTERIZATION OF SrSiO3/TiO2 PHOTOCATALYST FOR THE DEGRADATION OF CONGO RED DYE UNDER SUNLIGHT

Titanium dioxide and strontium silicate-loaded titanium dioxide photocatalysts are prepared via a simple chemical precipitation technique using titanium tetrachloride as the precursor solution in an alkaline medium. Different characterization techniques such as x-ray diffraction analyses, field emission scanning electron microscopic analyses, transmission electron microscopic analyses, energy dispersive x-ray analyses and bet surface area studies are carried out for the synthesized photocatalysts. The enhancement in the photocatalytic activity of the strontium silicate loaded titanium dioxide against the bare titanium dioxide catalyst is investigated using congo red dye as a model pollutant. The parameters such as catalyst concentration, pH and initial dye concentration are optimized to achieve maximum degradation of congo red dye using the modified titanium dioxide photocatalyst. The kinetic studies using the Langmuir-Hinshelwood model are investigated to study the rate and order of the photocatalytic dye degradation process.

Investigation of Sodium and Germanium Incorporated Strontium Silicate (Sr3-3xna3xsi3-3yge3yo9-Δ) as an Ionic Conductor

Investigation of Sodium and Germanium Incorporated Strontium Silicate (Sr3-3xna3xsi3-3yge3yo9-Δ) as an Ionic Conductor

Creation and research of new bioindifferent photocatalysts that use the energy of solar radiation to purify wastewater from pollutants

This work is devoted to the study of new bioindifferent photocatalysts that use the energy of solar radiation to purify water from organic pollutants. Photocatalytic materials were obtained by a previously developed low-temperature pyrolytic synthesis. Varying the bismuth content in the percursor mixture within 15-30 %, allows controlling the phase formation of the bismuth and strontium silicate phases. The samples obtained at 25 % bismuth in the precursor mixture (in terms of Bi2O3 %, wt.) show the highest photocatalytic activity with Bi12SiO2, Bi4Si3O12 formed in the catalyst composition. Photocatalytic activity of coatings with the predominance of bismuth silicates is inferior to coatings with the predominance of strontium bismuthates, but their greater hydrolytic stability is observed.

Efficient white light emission from a single silicate host with promising color quality for white light emitting diodes

Strontium silicate phosphors were synthesized via a solid-state route with different silicon sources as SiO2 and Si3N4. The phosphors synthesized with Si3N4 exhibited improved luminescence properties for white emission because of the coexistence of Sr3MgSi2O8 and Sr2SiO4 phases. Under UV excitation, white light was observed due to the combination of blue emission from Sr3MgSi2O8: Eu2+ and yellow emission from Sr2SiO4: Eu2+. The broad Eu2+ emission was explained on the basis of the dependency of crystal field strength on the site selection. The variation of Eu2+ ion concentration controlled the quality of the emitted light and at 5 mol% Eu2+, near white emission (0.30, 0.31) was obtained with external and internal quantum efficiencies of 50% and 68%, respectively. The WLEDs were fabricated by coating the present phosphors on an InGaN UV- LED chips and the EL spectrum displayed near white chromaticity (0.31, 0.33) with color rendering index of 80 and CCT of 6850 K. The results demonstrated the promising single host phosphors for near-UV white-light-emitting diodes.

3D Printing of Strontium Silicate Microcylinder-Containing Multicellular Biomaterial Inks for Vascularized Skin Regeneration.

The reconstruction of dermal blood vessels is essential for skin regeneration process. However, the lack of vascular structure, insufficient angiogenesis induction, and ineffective graft-host anastomosis of the existing skin substitutes are major bottle-necks for permanent skin replacement in tissue engineering. In this study, the uniform strontium silicate (SS) microcylinders are successfully synthesized and integrated into the biomaterial ink to serve as stable cell-induced factors for angiogenesis, and then a functional skin substitute based on a vascularization-induced biomimetic multicellular system is prepared via a "cell-writing" bioprinting technology. With an unprecedented combination of vascularized skin-mimicking structure and vascularization-induced function, the SS-containing multicellular system exhibits outstanding angiogenic activity both in vitro and in vivo. As a result, the bioprinted skin substitutes significantly accelerate the healing of both acute and chronic wounds by promoting the graft-host integration and vascularized skin regeneration in three animal models. Therefore, the study provides a referable strategy to fabricate biomimetic multicellular constructs with angiogenesis-induced function for regeneration of vascularized complex and hierarchical tissues.

Polymer - silicate nanocomposities: Package material for nanodevices as an EMI shielding

Strontium silicate nanoparticles were filled in the organic matrix of poly ethylene glycol, polyvinyl alcohol and polyvinyl pyrrolidone polymers. Different weight percentages were selected for the preparation of thin films on the glass substrate using spin coating technique. Prepared polymer nanocomposite films were characterized for their structural analysis and compositional details using powder X-ray diffraction. Amorphous polymer films with intense diffraction peaks at around 43.8° and 73° exhibited the crystalline phase when doped with strontium silicate in polymer blend matrix. Structural information shows the stable existence of crystalline nanoparticles in the polymer matrix. Dielectric and electrical properties of these samples were studied in the frequency range from 100 Hz to 5500 Hz. Dielectric constant decreased with increase in frequency and changed to different values based on the loading of different weight percentage of nanoparticles. With increase in frequency, the dipolar ordering of polymer-polymer decreased and strengthens the polymer-nanoparticles interaction. Polyvinyl alcohol with 3- wt% of poly ethylene glycol showed the low dielectric constant and dielectric loss as less than 0.03 confirms their improved dielectric properties. Hence, this composition can be used as a better insulating polymeric nanodielectric material which finds application in packaging of nanoscale electronic devises to have better electromagnetic shielding.

Correlation among photoluminescence and the electronic and atomic structures of Sr2SiO4:xEu3+ phosphors: X-ray absorption and emission studies

A series of Eu3+-activated strontium silicate phosphors, Sr2SiO4:xEu3+ (SSO:xEu3+, x = 1.0, 2.0 and 5.0%), were synthesized by a sol–gel method, and their crystalline structures, photoluminescence (PL) behaviors, electronic/atomic structures and bandgap properties were studied. The correlation among these characteristics was further established. X-ray powder diffraction analysis revealed the formation of mixed orthorhombic α'-SSO and monoclinic β-SSO phases of the SSO:xEu3+ phosphors. When SSO:xEu3+ phosphors are excited under ultraviolet (UV) light (λ = 250 nm, ~ 4.96 eV), they emit yellow (~ 590 nm), orange (~ 613 nm) and red (~ 652 and 703 nm) PL bands. These PL emissions typically correspond to 4f–4f electronic transitions that involve the multiple excited 5D0 → 7FJ levels (J = 1, 2, 3 and 4) of Eu3+ activators in the host matrix. This mechanism of PL in the SSO:xEu3+ phosphors is strongly related to the local electronic/atomic structures of the Eu3+–O2− associations and the bandgap of the host lattice, as verified by Sr K-edge and Eu L3-edge X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure, O K-edge XANES and Kα X-ray emission spectroscopy. In the synthesis of SSO:xEu3+ phosphors, interstitial Eu2O3-like structures are observed in the host matrix that act as donors, providing electrons that are nonradiatively transferred from the Eu 5d and/or O 2p–Eu 4f/5d states (mostly the O 2p–Eu 5d states) to the 5D0 levels, facilitating the recombination of electrons that have transitioned from the 5D0 level to the 7FJ level in the bandgap. This mechanism is primarily responsible for the enhancement of PL emissions in the SSO:xEu3+ phosphors. This PL-related behavior indicates that SSO:xEu3+ phosphors are good light-conversion phosphor candidates for use in near-UV chips and can be very effective in UV-based light-emitting diodes.