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To evaluate experimental dimethacrylate-based materials containing calcium orthophosphates or calcium silicate particles in terms of their optical, mechanical and Ca2+ release behaviour. Dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HAp), beta-tricalcium phosphate (β-TCP) or calcium silicate (CaSi) particles were added to a photocurable BisGMA/TEGDMA resin (1:1 in mols) at a 30 vol% fraction. Materials containing silanized or non-silanized barium glass particles were used as controls. Degree of conversion (DC) at the top and base of 2-mm thick specimens was determined by ATR-FTIR spectroscopy (n = 5). Translucency parameter (TP) and transmittance (%T) were determined using a spectrophotometer (n = 3). Biaxial flexural strength (BFS) and flexural modulus (FM) were determined by biaxial flexural testing after 24 h storage in water (n = 10). Ca2+ release in water was determined during 28 days by inductively coupled plasma optical emission spectrometry (n = 3). Statistical analysis was performed using ANOVA/Tukey test (DC: two-way; TP, %T; BFS and FM: one-way; Ca2+ release: repeated measures two-way, α = 5 %). Results: CaSi and β-TCP particles drastically reduced DC at 2 mm, TP and %T (p < 0.001). Compared to both controls, all Ca2+-releasing materials presented lower BFS (p < 0.001) and only the material with DCPD showed significantly lower FM (p < 0.05). The material containing CaSi presented the highest Ca2+ release, while among materials formulated with calcium orthophosphates the use of DCPD resulted in the highest release (p < 0.001). CaSi particles allowed the highest Ca2+ release. Notwithstanding, the use of DCPD resulted in a material with the best compromise between optical behaviour, DC, strength and Ca2+ release. • The addition of β-TCP and CaSi reduced degree of conversion, %T and translucency. • All particles negatively affected biaxial flexural strength. • The addition of DCPD reduced the flexural modulus in relation to the control. • The addition CaSi resulted in the greater release of Ca2+. [ABSTRACT FROM AUTHOR]

The solubility/degradability of bioactive glasses play crucial role in bone tissue engineering applications owing to the release of ions from their structure, which exert therapeutic effects on tissues. The present study evaluates the findings of a detailed investigation on the main features and solubility behaviors of newly formulated Nb incorporated glasses (Nb-BGs). New glass formulation in SiO 2 –CaO–Na 2 O–P 2 O 5 –CaF 2 –SrO–xNb 2 O 5 (x: 0.0, 0.5, 1.0, and 1.5 mol. %) system was successfully synthesized by melt-quenching technique. Glass composition was verified with Energy Dispersive X-ray Fluorescence spectrometer analysis and its amorphous nature, functional groups of the matrix and morphological features were identified via X-Ray diffraction analyses, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscope analysis, respectively. Network connectivity (NC) of the Nb-BGs was assessed with respect to the role of Nb 2 O 5 in the glass matrix as network former, modifier, or both. In order to evaluate the in vitro solubility of Nb-BGs, released concentrations of particular ions from the glass compositions were determined at certain time points and comprehensively discussed with several mathematical models such as zero-order, first-order, second-order, Higuchi, and Korsmeyer-Peppas for the first time. Results showed that the incorporation of Nb 2 O 5 (up to 1.5 mol. %) increased the density, oxygen density as well as NC values of newly formulated glasses. Si, Na and Ca ions which play a main role in well-defined Hench's mechanism followed mostly second-order release kinetics for all glasses in the mathematical models studied. When the Nb content increase (to 1.5 mol. %) in glass composition, the release mechanism of Si ion according to Korsmeyer-Peppas model shifts from the diffusion mechanism to an erosion-dominant release mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

To investigate the effect of hydrophilic/permeable polymer matrices on water sorption/solubility (WS/SL), Ca2+ release, mechanical properties and hydrolytic degradation of composites containing dicalcium phosphate dihydrate (DCPD) particles. Six composites were tested, all with 10 vol% of glass particles and either 30 vol% or 40 vol% DCPD. Composites containing 1BisGMA:1TEGDMA in mols (at both inorganic levels) were considered controls. Four materials were formulated where 0.25 or 0.5 of the BisGMA/TEGDMA was replaced by pyromellitic dianhydride glycerol dimethacrylate (PMGDM)/ polyethylene glycol dimethacrylate (PEGDMA). Composites were tested for degree of conversion (FTIR spectroscopy), WS/SL (ISO 4049) and Ca2+ release (inductively coupled plasma optical emission spectroscopy). Fracture toughness (FT) and biaxial flexural strength/modulus (BFS/FM) were determined after 24 h and 60 days in water. The contributions of diffusional and relaxational mechanisms to Ca2+ release kinetics were analyzed using the semi-empirical Salim-Peppas model. Data were analysed by ANOVA/Tukey test (alpha: 0.05). WS/SL was higher for composites containing PMGDM/PEGDMA compared to the controls (p < 0.001). Only at 40% DCPD the 0.5 PMGDM/PEGDMA composite showed statistically higher Ca2+ release than the control. Relaxation diffusion was the main release mechanism. Initial FT was not negatively affected by matrix composition. BFS (both DCPD fractions) and FM (30% DCPD) were lower for composites with hydrophilic/permeable networks (p < 0.01). After 60 days in water, composites with PMGDM/PEGDMA presented significant reductions in FT, while all composites had reductions in BFS/FM. Increasing matrix hydrophilicity/permeability significantly increased Ca2+ release only at a high DCPD fraction. • Replacing BisGMA/TEGDMA by PMGDM/PEGDMA increased composite WS/SL. • Increasing polymer hydrophilicity/permeability increased Ca2+ release. • The increase was significant only at the highest DCPD and PMGDM/PEGDMA fractions. • In the first two weeks, Fickian diffusion was the predominant mechanism for most tested materials. • In the long term, Ca2+ released occurred mostly due to relaxational diffusion. [ABSTRACT FROM AUTHOR]

Lithium disilicate (LD) glass-ceramics have adequate mechanical properties and are considered as a candidate for repairing large bone defects. However, LD glass-ceramic is an inherently inert restorative material, which cannot induce new bone tissue. In the present study, LD glass-ceramics were ion-exchanged at 235 °C for 16 h, 64 h and 128 h in a mixed salt bath of sodium nitrate and potassium nitrate (1:1 M ratio) respectively. A gradient concentration distribution of Na+-rich layer was obtained by Li+/Na+ exchange and Na+ ions were released from the Li+/Na+ exchanged LD glass-ceramics in an aqueous condition. The hydroxyapatite (HA) layer was formed on Li+/Na+ exchanged LD glass-ceramic and exhibited a significant exchange time-dependent after soaking in the simulated body fluid (SBF). Moreover, the Li+/Na+ exchange treatment could improve cell adhesion, proliferation and osteogenic differentiation of LD glass-ceramic significantly, and long-time treatment could achieve a better performance. Therefore, ion-exchange process is a feasible strategy to promote the surface biomineralization, cytocompatibility and osteogenesis of LD glass-ceramics. These results suggest that Li+/Na+ exchange is a promising process for LD glass-ceramic application in clinical orthopedic reconstruction. [ABSTRACT FROM AUTHOR]

to evaluate the effect a glass ionomer cement (GIC) containing hydroxyapatite (HAp) or calcium silicate (CaSi) particles on mineral content and mechanical properties of demineralized dentin. Ion release and compressive strength (CS) of the cements were also evaluated. GIC (Fuji 9 Gold Label, GC), GIC+ 5%HAp and GIC+ 5%CaSi (by mass) were evaluated. Ion release was determined by induced coupled plasma optical emission spectroscopy (Ca2+/Sr2+) or ion-specific electrode (F-) (n = 3). A composite (Filtek Z250, 3 M ESPE) was used as control in remineralization tests. Demineralized dentin discs were kept in contact with materials in simulated body fluid (SBF) at 37 °C for eight weeks. Mineral:matrix ratio (MMR) was determined by ATR-FTIR spectroscopy (n = 5). Dentin hardness (H) and elastic modulus (E) were determined by nanoindentation (n = 10). CS was tested after 24 h and 7d in deionized water (n = 12). Data were analyzed by ANOVA/Tukey test (α = 0.05). Ca2+ and Sr2+ release was higher for the modified materials (p < 0.05). Only GIC+ 5%HAp showed higher F- release than the control (p < 0.05). All groups showed statistically significant increases in MMR, with no differences among them after 8 weeks (p > 0.05). No differences in dentin H or E were observed among groups (p > 0.05). HAp-modified GIC showed increased initial CS, while adding CaSi had the opposite effect (p < 0.05). After 7 days, GIC+ 5%CaSi presented lower CS in relation to control and GIC+ 5%HAp (p < 0.05). GIC modification with HAp or CaSi affected CS and increased ion release; however, none of the groups showed evidence of dentin remineralization in comparison to the negative control. • The replacement of GIC glass by HAp particles increased initial (24 h) GIC strength. • The replacement of GIC glass by CaSi particles reduced GIC strength (24 h and 7d). • The presence of HAp or CaSi particles increased Ca2+, Sr2+ and F- release. • The addition of 5% HAp or CaSi did not increase GIC´s remineralizing potential. [ABSTRACT FROM AUTHOR]

To investigate the depth of cure (DoC), fracture toughness (K IC) and wear of ion releasing resin-based composite (RBC) restorative materials. Two ion releasing RBCs, Activa (ACT) and Cention-N (CN) were compared to a conventional RBC (Z350) and a resin-modified glass ionomer cement (Fuji-II-LC). The DoC was measured in a 10-mm deep semi-circular metal mold with a 2-mm internal radius (n = 8). The molds were irradiated from one end for 20-s. The Knoop hardness (KH) was measured at 0.5-mm intervals from the surface after the specimens had been stored at 37 °C for 24-h. To measure the K IC , single-edge-notched specimens (n = 15/group) were prepared (25×5x2.5-mm) for a 3-point bending test and then stored for either 1 or 30-days in water at 37 °C. Disk-shaped specimens (n = 10) were subjected to 250,000-load cycles of 49-N using a chewing simulator against spherical steatite antagonists. DoC and wear data were analyzed by one-way ANOVA and Tukey post hoc tests (p ≤ 0.05). K IC data were analyzed by two-way ANOVA and one-way ANOVA, and the Tukey post hoc test (p ≤ 0.05). In addition, an independent t-test was used to determine if storage time had any effect (α = 0.05) on the K IC of each material. Maximum hardness value was the highest for Z350 and the lowest for ACT. The depth at which 80% of the maximum KH, was the highest for CN (9.2 mm) and the lowest for Z350 (2 mm). All tested materials met the manufacturers' claims for DoC. After 1-day, the highest K IC values were recorded for ACT and the lowest for Fuji-II-LC. Water storage (30-days) significantly reduced the K IC value for all materials except Fuji-II-LC. The highest wear rate values were recorded for CN followed by ACT. All tested materials met their manufacturers' claims for DoC. Water storage for 30-days significantly reduced the fracture toughness for ACT and CN. Wear was significantly higher for ACT and CN. • Depth of cure (DoC) was determined using Knoop microhardness profiles 24 h post cure. • All tested materials met the manufacturers' claims for DoC. • 30 d storage in 37 °C water significantly decreased K IC of ion releasing resin based composite. • Ion releasing resin based composite showed less wear resistance after cyclic loading. [ABSTRACT FROM AUTHOR]

Analyze the effects of the functionalization of pre-functionalized GIC particles with chlorhexidine on the physicochemical properties and antimicrobial activity. Four groups were prepared: (1) GIC (Bioglass R - Biodinamica) - control group; (2) GIC-CHX 1%: Group containing 1% pre-reacted CHX particles; (3) GIC-CHX 2.5%: Group containing 2.5% pre-reacted CHX particles; (4) GIC-CHX 5%: Group containing 5% pre-reacted CHX particles. Hourglass-shaped specimens (10 mm × 2 mm x 1 mm) were fabricated for mechanical tests including cohesive strength (n = 12), modulus of elasticity (n = 12) and microhardness (n = 10). Discs (10 mm × 2 mm) were prepared for the analysis of Ca+2, PO 4 − and F− ions release (n = 3), and roughness (n = 12). To evaluate the setting time, a Gilmore needle was used according to ISO 9917–1:2016. Disk-shaped specimens (5 × 1mm) were manufactured and subjected to bacterial activity (n = 9) (Streptococcus mutans ATCC 159). Modulus, roughness, setting time and ions release (Ca+2, PO 4 −, and F−) there were no statistically significant differences among the groups (p > 0.05). The setting time did not change with the incorporation of CHX. The GIC-CHX 2.5% and GIC-CHX 5% groups exhibited superior antibacterial activity compared to the control group and GIC-CHX 1% (p < 0.001). The GIC-CHX 5% group showed the highest microhardness values (p < 0.041), cohesive strength (p < 0.009) when compared to the control group. The pre-reacted CHX in GICs was able to confer antimicrobial activity, improve cohesive strength, microhardness, and did not impair ion release, setting time, and roughness. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the degradation of inert glass fillers which are commonly used in conventional resin-based composites to provide radiopacity, reduce the polymerization shrinkage and improve the mechanical properties. 75 mg of five different glass powders (1 µm) was immersed separately into 50 mL of acetic acid (pH 4) and tris buffer (pH 7.4) for up to 4 weeks. At each time point the glass powder was filtered and dried for characterization using ATR-FTIR and XRD to assess the degradation behavior and crystallization. ICP-OES, ISE and pH measurements were performed on the supernatant solutions to monitor the pH and ion release. Although FTIR and XRD analysis showed no significant glass degradation or crystallization upon immersion, there was a substantial release of ions from the inert fillers, especially from BABFG and CDL. Barium release for these fillers were 270 and 165 ppm respectively. G018–373 glass presented the lowest ion release followed by GM27884 and BABG. The ion release was more pronounced in acidic conditions compared to neutral conditions apart from the fluoride release. Inert glasses are not as inert as previously thought. This may result in leaching of ions, potentially causing toxicity, reduction in mechanical properties, increased wear and subsequent failure of the composite material. The ions released from the inert glass may interfere with other glass fillers such as bioactive glass fillers, inhibiting degradation of the bioactive glass, beneficial ion release from the bioactive glass, pH neutralization and apatite formation. [ABSTRACT FROM AUTHOR]

The biomedical engineering advances in the last years have been rising demand for multifunctional biomaterials. Bioactive glass (BG) submicron particles are potential candidates for the formulation of composites with improved dispersion and homogeneity between the constituents. This work presents the preparation of SiO 2 –Na 2 O–CaO–P 2 O 5 glass-derived powders composed of particles with homogenous shapes and sizes between 300 and 500 nm. Two types of synthesis were employed for the preparation of the BG powders, the melt-quenching method, and a citric acid-assisted sol-gel route at a low citric acid concentration (0.005 mol L−1). The morphology of the particles was achieved by a low-energy process using a ball mill. These powders were characterized for their structure and surface area and evaluated for in vitro mineralization and antibacterial behavior. X-ray diffraction (XRD) analysis revealed different crystalline silicate phases in the sol-gel-derived powder and confirmed the amorphous structure of the melt-quenching-derived one. The surface of the particles was covered by hydroxycarbonate-apatite (HCA) after five days in simulated body fluid (SBF). The antibacterial activity against Staphylococcus aureus was higher for the sol-gel-derived powder, showing inhibition >99% of the bacteria growth in 24 h for all concentrations studied. These BG-based powders present a set of characteristics useful for the formulation of multifunctional composites for orthopedic applications. [ABSTRACT FROM AUTHOR]

This study aimed to develop and characterize an ion-releasing experimental fiber-reinforced flowable composite (Bio-SFRC) and dentin treatment solution made of poly(acrylic acid) (PAA) with a high molecular weight. In addition we also evaluated the interface structure and mineralization potential between the Bio-SFRC and dentin. Some mechanical properties (flexural properties and fracture toughness) of Bio-SFRC in comparison with commercial inert (G-aenial Flo X) and ion-releasing materials (ACTIVA-BioActive Base/Liner and Fuji II LC) were assessed (n = 8/group). Calcium-release at different time-points was measured during the first six weeks by using a calcium-ion selective electrode. Surface analysis of composites after being stored in simulated body fluid (SBF) was investigated by using SEM/EDS. Dentin disks (n = 50) were prepared from extracted sound teeth and demineralization was simulated by acid etching. SEM/EDS was used to evaluate the microstructure of dentin on the top surface and at interface with composites after being stored in SBF. Bio-SFRC showed higher fracture toughness (1.6 MPa m1/2) (p < 0.05) compared to Flo X (1.2 MPa m1/2), ACTIVA (1 MPa m1/2) and Fuji II LC (0.8 MPa m1/2). Accumulative calcium release after six weeks from Bio-SFRC (15 mg/l) was higher than other tested ion-releasing materials (≈ 6 mg/l). Mineralization was clearly seen at the interface between treated dentin and Bio-SFRC. None of the commercial tested materials showed signs of mineralization at the interface and dentinal tubules remained open. Significance. Developing such reinforced ion-releasing flowable composite and PAA solution might offer the potential for mineralization at the interface and inside the organic matrix of demineralized dentin. [ABSTRACT FROM AUTHOR]

Most of the conventional in vitro models to test biomaterial-driven vascularization are too simplistic to recapitulate the complex interactions taking place in the actual cell microenvironment, which results in a poor prediction of the in vivo performance of the material. However, during the last decade, cell culture models based on microfluidic technology have allowed attaining unprecedented levels of tissue biomimicry. In this work, we propose a microfluidic-based 3D model to evaluate the effect of bioactive biomaterials capable of releasing signaling cues (such as ions or proteins) in the recruitment of endogenous endothelial progenitor cells, a key step in the vascularization process. The usability of the platform is demonstrated using experimentally-validated finite element models and migration and proliferation studies with rat endothelial progenitor cells (rEPCs) and bone marrow-derived rat mesenchymal stromal cells (BM-rMSCs). As a proof of concept of biomaterial evaluation, the response of rEPCs to an electrospun composite made of polylactic acid with calcium phosphates nanoparticles (PLA+CaP) was compared in a co-culture microenvironment with BM-rMSC to a regular PLA control. Our results show a significantly higher rEPCs migration and the upregulation of several pro-inflammatory and proangiogenic proteins in the case of the PLA+CaP. The effects of osteopontin (OPN) on the rEPCs migratory response were also studied using this platform, suggesting its important role in mediating their recruitment to a calcium-rich microenvironment. This new tool could be applied to screen the capacity of a variety of bioactive scaffolds to induce vascularization and accelerate the preclinical testing of biomaterials. For many years researchers have used neovascularization models to evaluate bioactive biomaterials both in vitro , with low predictive results due to their poor biomimicry and minimal control over cell cues such as spatiotemporal biomolecule signaling, and in vivo models, presenting drawbacks such as being highly costly, time-consuming, poor human extrapolation, and ethically controversial. We describe a compact microphysiological platform designed for the evaluation of proangiogenesis in biomaterials through the quantification of the level of sprouting in a mimicked endothelium able to react to gradients of biomaterial-released signals in a fibrin-based extracellular matrix. This model is a useful tool to perform preclinical trustworthy studies in tissue regeneration and to better understand the different elements involved in the complex process of vascularization. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Blue oxides generated by anodization and plasma treatment were investigated. • Anodized specimen had better corrosion resistance than plasma treated specimen. • Vanadium enrichment at outermost oxide surface of plasma treated specimen. • Outermost oxide of plasma treated specimen is highly porous. • Oxide formed by anodization is more biocompatible than plasma treated one. This work aims to evaluate the corrosion and biocompatibility properties of oxide films generated on Ti6Al4V alloys using both traditional and novel methods. Oxide films were generated by anodization and plasma treatment to achieve a blue surface finish. The oxide films were then characterized and compared to a native film formed on the Ti6Al4V. Electrochemical tests, incorporating potentiodynamic tests and electrochemical impedance spectroscopy, were employed to define the electrochemical resistance of oxides in an environment simulating biological exposure. In vitro tests were conducted to study ion release and biocompatible properties over a 6-week period of exposure to a 0.9 wt% NaCl solution, at body temperature. Various spectroscopic techniques, including ToF-SIMS, XRD, and Raman analysis, were used to study the structure and chemistry of the oxide films. The sub-surface layer was analysed by microstructural investigation. The type of oxidation was found to have a key influence on the oxide composition, especially with respect to the depth distribution of the individual alloy elements through the oxide film. The oxidation process determines which of the alloying elements are released into the environment, as a result of the corrosion reactions. [ABSTRACT FROM AUTHOR]

Recurrent inflammation, intense bacterial infections, and inadequate blood vessel growth make diabetic wounds non-healing. Under pathological environment, cellular functions are also inhibited. In this paper, we developed a novel in situ injectable photo-crosslinking hydrogel embedded with heterojunction Ag@ZnO nanoparticles (NPs) which exhibit dual-channel synergistic ion release and reactive oxygen species (ROS) production for anti-bacteria and cutaneous regeneration. This novel hydrogel platform can be introduced onto any irregular wound and form gelation with 395 nm UV light irradiation in only 5 s. After being affixed to the wound, Ag+ and Zn2+ can be released as the first interaction for wound healing. Foremost, the heterojunction formed on interface of Ag and ZnO has the ability to capture oxygen and water to instigate the generation of a "ROS storm", which can disrupt the structural integrity of bacteria, trigger the leakage of bacterial cytoplasmic content, enhance angiogenesis by activating VEGF and CD31 expression, and stimulate the steps of wound healing. The continuous release of Ag+, Zn2+ and "ROS storm" collaboratively drive bacterial deactivation, suppress inflammation, promote cellular proliferation, collagen deposition and angiogenesis. These effects significantly accelerate diabetic chronic wounds healing. Therefore, such dual-channel synergistic hydrogel platform might provide a promising new insight to diabetic chronic wound treatment. [Display omitted] • In situ injectable hydrogel embedded with nanoparticles can be adapted to wound and crosslinked by light for few seconds. • Zinc and silver ions releasing and "ROS storm" generation enhance the antibacterial effect as dual-channel synergistic interaction. • The hydrogel reduce inflammation, promote cell proliferation and angiogenesis for the therapy of diabetic chronic wounds. [ABSTRACT FROM AUTHOR]

[Display omitted] Bioactive glasses (BAGs) have been researched extensively for dentistry due to their favourable biocompatibility and hard tissue bonding ability. However, the specific application of BAGs produced through sol-gel synthesis in restorative dentistry has not been reviewed previously. This review provides a comprehensive account of the principles behind sol-gel derived BAGs and their investigation for dental tissue restoration materials. A search for in vitro and in vivo studies was performed using the databases Web of Science®, Medline®, Scopus® and Google Scholar®. Articles published over the past 20 years were selected and data on the BAG composition and morphology was extracted. Analysis of the effect of specific BAG additives on the properties of experimental dental materials was also performed. A majority of BAG particles investigated were spheres ranging in size from 5 nm to ~650 µm. Sol-gel BAGs are mainly applied in the treatment of hypersensitive dentine and for pulp-dentine tissue engineering, while a handful have been used in target drug delivery. BAG fillers are promising additives that result in improved biological properties, antibacterial effects, hardness, acid buffering and remineralization. Unfortunately, some detrimental effects on optical properties have been observed with BAG addition. Additionally, in vivo data, investigations into radiopacity and standardization of test protocols are identified as areas for improvement and further studies. Future work should consider the pertinent issues raised in order to improve the quality of available data and expand knowledge in this area of dental biomaterials research and development. [ABSTRACT FROM AUTHOR]

Since the discovery of 1970s, bioactive glass has been a hot topic of research because of its excellent biological activity, which makes it a material that can repair and replace human bone tissue organs. In this work, the bioactive glasses in the system SiO 2 –P 2 O 5 –Na 2 O–CaO–F with different amounts of strontium oxide (SrO) and zinc oxide (ZnO) were prepared by the conventional melt quenching technology. The hydroxyapatite (HA) forming ability, ion release and antibacterial activity of these prepared glasses were investigated and the obtained results illustrated that SrO-doped samples had a better ability to form HA in modified simulated body fluid (MSBF) than ZnO-doped samples. As the immersion time of the sample in MSBF increased, the content of HA phase gradually increased. In the same immersion time, the formation ability of HA and the variation of SrO substitution amount showed a non-linear trend, which is mainly related to the influence of SrO content on the glass network structure. The results of ion concentration showed that the formation of HA was the result of the comprehensive action of various ions in the solution, especially the release rate of Si4+ ions, which had a direct impact on the formation ability of HA. The antibacterial test illustrated that the difference in antibacterial activity of bacteria solution at different sample concentrations may be related to the high pH environment and the osmotic effects caused by the non-physiological concentration of ions in the solution. The glass sample contained 4 wt% SrO showed the minimum bactericidal concentration at 64 mg/mL. The glass samples prepared in this experiment had good biological activity and antibacterial effect, making them suitable for using in dentistry and orthopedic applications, as well as providing a valuable composition reference for the preparation of bioactive glass with excellent comprehensive properties. [ABSTRACT FROM AUTHOR]

Background: Among various options suggested to prevent hip instability after total hip replacement, the MDM-tritanium (modular dual mobility) cup features a cobalt-chrome liner (CoCr) positioned in a titanium acetabular shell and matched with a mobile insert in highly cross-linked annealed X3 polyethylene. The purpose of this study aimed to confirm whether there was no significant release of ions (Co and Cr) or higher occurrence of dislocation or even cases of aseptic loosening of the cementless shell with the use of MDM-tritanium cups at minimum of 5-year follow-up.Methods: The clinical study was carried out on a homogeneous consecutive and nonselective series with 102 MDM cups (98 patients) implanted in 2 centers. This MDM-tritanium cup had been systematically used for surgical revisions (70% of cases) or for patients with major hip dysplasia or in elderly patients with poor bone quality. A biological assessment of ion releases has been performed in a specific cohort of 39 cases that had an internal ceramic head.Results: None of the following complications was observed: no case of immunoallergic event, no aseptic loosening, and the dislocation rate was 4.9% involving only the difficult primary and revision cases. The clinical results were encouraging, with 89.7 points for Harris Hip Score, 41.16 points/48 for the OHS-12. The Agora Roentgenographic Assessment (ARA) radiologic score was graded "excellent" in 94.4%. The MDM-tritanium survivorship with revision for any cause in 102 cups at 7.95 years was 92.7%.Conclusion: Based on the results of our first 102 cases, there were no immunoallergic complications-contrary to what was initially feared with the CoCr bearing-titanium pair-and no postoperative instability, including for complex primary and revisions total hip replacements.Level Of Evidence: Individual Cohort Study: 2B. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine and compare nickel and chromium ion release from traditional stainless steel and nickel titanium wires and newer esthetic archwires under different pH conditions, for different time intervals. Ten pieces of 10-mm segments of five different orthodontic archwires were submerged in buffer solutions of pH 4.0, 5.5, and 7.0, for 4 and 13 weeks. The sample solutions were analyzed using ICP-MS. First, the results were analyzed by three-way ANOVA to determine any significant differences in metal concentration (ppb) between the different groups. Then, a post-hoc multiple pairwise comparison by Tukey's Studentized Range (HSD) Test was conducted to further compare the different materials and pH conditions. For nickel, uncoated NiTi had the highest nickel ion release (ppb), while AO Iconix had the lowest average nickel ion release, with a significant difference (p < 0.0001). The average nickel release increased with time and decreased with pH. For chromium, materials with uncoated stainless steel had the highest average chromium ion release, whereas AO Iconix had the lowest average chromium ion release, with a statistically significant difference (p < 0.0001). Chromium ion release increased with time and decreased with pH. There were significant differences in metal ion release between different pH conditions, materials, and time points. The metal ion release increased with increase in time and decrease in pH. Overall, the coated archwires showed less metal ion release than the uncoated wires. [ABSTRACT FROM AUTHOR]

Cerium (Ce)-substituted diopsides (CaMgSi 2 O 6) with enhanced mechanical strength and bioactivity were fabricated by precipitation method, followed by annealing at 1000 °C for 4 h. The mineralogical, morphological, in vitro biomineralization, degradation, and mechanical properties were investigated in order to assess the factors and mechanisms affecting the resultant properties. The X-ray diffractometer results showed that the onset of substitutional solid solubility in 0.25 mol Ce would result in new phase formation (cerium dioxide [CeO 2 ], and magnesium silicate [MgSiO 3 ]) further causing lattice instability. With increasing Ce dopant levels to 1.00 mol, the initial CaMgSi 2 O 6 phase was completely replaced by new phases. The field-emission scanning electron microscopy results indicated that the 0.25 mol Ce had the best biomineralization performance in vitro, while less hydroxyapatite precipitates were found with further increasing Ce dopant levels, suggesting the new phases led to the hindrance of precipitates. The weight loss values indicated that the high dissolution rate of ions in the matrix was observed in the pure sample, while the high readsorption rate of ions in the simulated body fluid (SBF) occurred with increasing Ce dopant levels. The pH value and the inductively coupled plasma-mass spectrometer results suggested that the release of Ca and Mg ions controlled the pH value. The mechanical strength of matrices before SBF immersion was related to the phase transformation, the elastic modulus of CeO 2 and CaMgSi 2 O 6 , and the release of Mg ions, while the mechanical strength of matrices after SBF immersion was dominated by the structure of matrices. [ABSTRACT FROM AUTHOR]

• Manual mixing with water results in microstructural changes, with lower setting time and lower calcium ion release. • Manual mixing required more liquid added to the mixture to obtain a similar consistency and flow to the control. • Increasing the amount of Biodentine liquid increases the calcium ion release but also increases the setting time. • Following the manufacturer's instruction for the mixing of Biodentine guarantees the materials characteristics and clinical performance. The water to powder ratio and method of mixing is important for the properties of hydraulic cements. For this purpose a number of clinicians prefer premixed materials. Dental manufacturing companies provide predosed materials, however the manufacturer instructions are not always adhered to. The aim of this research is to investigate physical and chemical alterations of the tricalcium silicate‐based cement Biodentine when manipulated according to the manufacturer's instructions (control) or changing the doses and mixing of the material components. 6 groups were constituted according to different mixing and dosing of powder and liquid. The hydrated cements were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Calcium ion concentration of the leachate was also investigated. Assessment of the physical characteristics included setting time and microhardness. Microstructural differences were visible only in the Biodentine mixed manually with water, in which early hydration rate was also affected, with lower calcium ion release. Increase of Biodentine liquid increased the calcium ion release, but also increased the setting time. Manual manipulation required more liquid (both water and Biodentine liquid) added to the mixture to guarantee a similar consistency to the control. A decrease in setting time was also noted. All groups showed higher values of microhardness at 24 h compared to the freshly set materials. In the freshly set materials, there was an overall decrease in microhardness in all groups when compared to group control, particularly significant when increasing the dosage of Biodentine liquid. When mixing Biodentine, altering the mixing procedure in terms of type and amount of liquid added to the powder and mixing device chosen has an effect on the physical, chemical and mechanical characteristics and surface topography of the material, when compared to Biodentine mixed according to the manufacturer's recommendations. Hence, the manufacturer's instructions should be strictly followed. [ABSTRACT FROM AUTHOR]

Coral reefs face unprecedented threats from climate change and human activities, making reef restoration increasingly important for the preservation of marine biodiversity and the sustainability of coastal communities. One promising restoration method relies on coral breeding and larval settlement, but this approach requires further innovation to achieve high rates of settlement and survival. In this study, we built on our previous work engineering lime mortar-based coral settlement substrates by investigating three different compositions of a natural hydraulic lime (NHL) base material as well as composite NHL substrates containing alkaline earth metals. These materials were tested with larvae of three reef-building Caribbean coral species: Orbicella faveolata (Mountainous star coral), Diploria labyrinthiformis (Grooved brain coral), and Colpophyllia natans (Boulder brain coral). We found that the base material composition, including its silicate and calcium carbonate (CaCO 3) content, as well as the addition of the inorganic additives strontium carbonate (SrCO 3), magnesium carbonate (MgCO 3), and magnesium sulfate (MgSO 4), all influenced coral larval settlement rates. Overall, NHL formulations with lower concentrations of silicate and higher concentrations of calcium, strontium, and magnesium carbonates significantly increased coral settlement. Further, when dissolved ions of magnesium and strontium were added to seawater, both had a significant effect on larval motility, with magnesium promoting settlement and metamorphosis in C. natans larvae, supporting the observation that these additives are also bioactive when incorporated into substrates. Our results demonstrate the potential benefits of incorporating specific inorganic ion additives such as Mg2+ and Sr2+ into substrates to facilitate early coral life history processes including settlement and metamorphosis. Further, our results highlight the importance of optimizing multiple aspects of coral substrate design, including material composition, to promote settlement and survival in coral propagation and reef restoration. [ABSTRACT FROM AUTHOR]

• An in vitro saliva-drop setting was assembled to evaluate ion-release properties. • GIC containing BioUnion filler releases Zn2+ and F− under acidic conditions. • Re-uptake of Zn2+ and F− in the GIC could be obtained. • Release of Zn2+ from the GIC after recharging hinders biofilm formation. A glass-ionomer cement (GIC) containing BioUnion filler has been reported to release Zn2+ under acidic conditions and to inhibit oral bacteria on its surface. However, previous results are based on in vitro experiments under static conditions. This study aimed to assemble an in vitro saliva-drop setting to simulate in vivo conditions of the oral cavity and to investigate the ion releasing and recharging properties of the GIC containing BioUnion filler. The effective concentrations of Zn2+ and F− against Streptococcus mutans and saliva-derived multi-species biofilms were determined. Artificial saliva was dropped on the GIC containing BioUnion filler using the in vitro saliva-drop setting assembly and was periodically replaced with acetic acid. Ion release/recharge properties were investigated by measuring the release concentrations of Zn2+ and F−. The concentration of Zn2+ released from the BioUnion filler-containing GIC during seven days with repeated exposure to acid could be maintained at the level to inhibit S. mutans and saliva-derived multi-species biofilm formation. Moreover, the BioUnion filler-containing GIC could be recharged with Zn2+ and F− by the application of a tooth gel containing Zn2+ and F−. The release concentration of Zn2+ after recharging was significantly higher than the effective concentration of Zn2+ to hinder S. mutans and saliva-derived multi-species biofilm formation on material surfaces. The GIC containing BioUnion filler was shown to have the potential to inhibit biofilm formation in the oral cavity. In addition, recharging Zn2+ and F− would further enhance the effect of the GIC containing BioUnion filler. [ABSTRACT FROM AUTHOR]

Orthopedic and dental implants made of β-type Ti alloys have low elastic modulus which can better relieve the stress shielding effects after surgical implantation. Nevertheless, clinical application of β-type Ti alloys is hampered by the insufficient mechanical strength and gradual release of pro-inflammatory metallic ions under physiological conditions. In this study, the β-type Ti-45Nb alloy is subjected to high-pressure torsion (HPT) processing to refine the grain size. After HPT processing, the tensile strength increases from 370 MPa to 658 MPa due to grain boundary strengthening and at the same time, the favorable elastic modulus is maintained at a low level of 61-72 GPa because the single β-phase is preserved during grain refinement. More grain boundaries decrease the work function and facilitate the formation of thicker and less defective passive films leading to better corrosion resistance. In addition, more rapid repair of the passive layer mitigates release of metallic ions from the alloy and consequently, the inflammatory response is suppressed. The results reveal a strategy to simultaneously improve the mechanical and biological properties of metallic implant materials for orthopedics and dentistry. The low modulus Ti-45Nb alloy is promising in addressing the complication of stress shielding induced by biomedical Ti-based materials with too-high elastic modulus. However, its insufficient strength hampers its clinical application, and traditional strengthening via heat treatments will compromise the low elastic modulus. In the current study, we enhanced the ultimate tensile strength of Ti-45Nb from 370 MPa to 658 MPa through grain-refinement strengthening, while the elastic modulus was maintained at a low value (61-72 GPa). Moreover, substrate grain-refinement has been proved to improve the corrosion resistance of Ti-45Nb with reduced inflammatory response both in vitro and in vivo. A relationship between the substrate microstructure and the surface passive layer has been established to explain the beneficial effects of substrate grain-refinement. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, numerous studies have analyzed the role of bioactive glass (BAG) as remineralizing additives in dental restorative composites. This current review provides a critical analysis of the existing literature, particularly focusing on BAGs prepared via the melt-quench route that form an "apatite-like" phase when immersed in physiological-like solutions. Online databases (Science Direct, PubMed and Google Scholar) were used to collect data published from 1962 to 2020. The research papers were analyzed and the relevant papers were selected for this review. Sol–gel BAGs were not included in this review since it is not a cost-effective manufacturing technique that can be upscaled and is difficult to incorporate fluoride. BAGs release Ca2+, PO 4 3− and F− ions, raise the pH and form apatite. There are numerous published papers on the bioactivity of BAGs, but the different glass compositions, volume fractions, particle sizes, immersion media, time points, and the characterization techniques used, make comparison difficult. Several papers only use certain characterization techniques that do not provide a full picture of the behavior of the glass. It was noted that in most studies, mechanical properties were measured on dry samples, which does not replicate the conditions in the oral environment. Therefore, it is recommended that samples should be immersed for longer time periods in physiological solutions to mimic clinical environments. BAGs present major benefits in dentistry, especially their capacity to form apatite, which could potentially fill any marginal gaps produced due to polymerization shrinkage. [ABSTRACT FROM AUTHOR]

• A SiO 2 -CaO-CaF 2 -Na 2 O Alkasite glass close to the composition used in Cention N raises the pH and releases calcium and fluoride ions. • The glass forms Fluorapatite upon immersion in artificial salivas containing orthophosphate ions. • The Fluorapatite formation is favoured in artificial salivas with higher pH and orthophosphate concentrations. • The increase in pH and the ion release are attractive features of a glass for a bioactive restorative designed to prevent secondary caries. To characterise the ion release, pH changes and apatite formation of a phosphate free bioactive glass. A SiO 2 -CaO-CaF 2 -Na 2 O glass was synthesized by a melt route with a composition close to the reactive glass in the commercial Cention N® composite. The glass was characterized after immersion in three media: Artificial Saliva pH4 (AS4) Artificial Saliva pH7 (AS7) and in a high phosphate artificial saliva at pH6.5 (AS6.5). The pH and fluoride release were measured using a pH meter and an ion selective electrode. The concentration of Ca, P, Na and Si were measured by ICP-OES. The glass powders after immersion were characterized by FTIR, X-ray powder diffraction and 19F MAS-NMR. The glass increased the pH in all three media. Fluoride was detected in all three media but was much higher in AS 6.5. Calcium fluoride formed in AS4 with a small amount of fluorapatite at long immersion times. Fluorapatite and calcium fluoride formed in AS7, whilst in AS6.5 fluorapatite formed. The ion concentrations in solution after immersion reflected the glass composition and the immersion media with fluorapatite being favoured by higher pHs and phosphate contents in the media. The results demonstrated the ability of the glass to increase the pH and to form fluorapatite in phosphate containing media. This may explain the low incidence of secondary caries found in the commercial composite. Unlike the commercial composite evidence was found for the precipitation of fluorite, which will act to reduce the release of fluoride for preventing secondary caries. [ABSTRACT FROM AUTHOR]

• CPP-ACP added to a GIC was distributed throughout the cement. • GIC can be recharged with CPP-ACP/F by topical application to the cement. • Recharging enhanced calcium, phosphate and fluoride ion release from the cement. • Recharging increased the surface hardness (acid resistance) of the cement. • Daily recharging of GIC may increase longevity of the cement and enhance caries protection. To assess the effect of CPP-ACP/F recharging on ion release and hardness of GIC Fuji-Triage (VII) and Fuji-Triage-EP (VII-EP) containing CPP-ACP/F. CPP-ACP distribution in Fuji-Triage-EP was determined using immunofluorescence. Thirty blocks of Fuji-Triage and Fuji-Triage-EP with the same surface area were placed individually in 5 mL of 50 mM lactic acid (pH 5) for three days. Every 12 h ten Fuji-Triage and ten Fuji-Triage-EP blocks were treated with 2 mL of either MI Paste Plus (CPP-ACP/F) solution (1 g paste + 4 mL water), Placebo MI paste solution (no CPP-ACP/F), or distilled water for 2 min. After each 2 min treatment the blocks were rinsed with distilled water and placed back into the acid. Calcium, inorganic phosphate and fluoride levels in the acid solution were measured using atomic absorption spectrophotometry, colorimetry and ion specific electrode respectively. Vickers surface hardness of the GIC was also determined. Data were analysed using a two-sample t-test and one-way ANOVA with a Bonferroni-Holm correction for multiple comparisons. CPP-ACP was distributed throughout Fuji-Triage-EP. Significantly (p < 0.001) higher calcium, inorganic phosphate and fluoride ion release and greater surface hardness (acid resistance) was observed in both GIC's treated with the CPP-ACP/F paste. Fuji-Triage-EP released higher ion levels and exhibited greater surface hardness (acid resistance) than Fuji-Triage. Topical application of CPP-ACP/F paste to GIC Fuji-Triage-EP recharged ion release and increased surface hardness (acid resistance) which may help improve properties and resistance to degradation as well as improve ion release for caries control. [ABSTRACT FROM AUTHOR]

Physical vapor deposition (PVD) technology can modify the surface properties of equipment without changing the biomechanical properties of the substrate, and has been increasingly used in medical devices. Medical devices can be divided into surgical instruments, implantable medical devices and interventional medical devices according to the object and the way of application. For the defects of different medical devices during use, this paper reviews the development and application of PVD coatings to improve the performance and extend the life of medical devices. Finally, the development of PVD coatings for medical devices is expected. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the ion release, pH changes and apatite formation ability of two potentially bioactive composites Cention N (CN) and Activa (ACT). Ion release and apatite formation was investigated in three different immersion media: Tris buffer pH 7.3 (TB), Artificial Saliva pH 4 (AS4) and Artificial Saliva pH 7 (AS7) in order to mimic the conditions present in the mouth. Fluoride release was followed using an ion selective electrode, whilst all other ions were determined by inductively coupled plasma optical emission spectroscopy. Apatite formation was followed by FTIR and XRD. SEM was used to follow glass degradation and apatite formation on both polished cross-sections and surfaces of the composites. ACT released very few ions including fluoride upon immersion in TB and AS7, but released more ions including significant quantities of Al in AS4. This would suggest the glasses in ACT are acid degradable fluoro-alumino-silicate glasses similar to the glasses used in glass ionomer cements. There was no evidence of any apatite formation with ACT. CN released more ions in TB and AS7 than ACT and formed an apatite like phase in AS7. The calcium fluoro-silicate glass in CN was observed to degrade significantly in AS4. CN has bioactive properties that may explain the low incidence of secondary caries found clinically with this composite. [ABSTRACT FROM AUTHOR]

• The concentration of fluoride does not reflect the rate of fluoride release. • Calcium phosphate formula and/or additives would influence fluoride ion release. • CPP-ACP or Bioglass® could be source of bioavailable calcium and phosphate. To compare ion release characteristics of three different dental varnishes either containing CPP-ACP and fluoride (CPP-ACPF, MI Varnish GC, Japan), bioactive glass and fluoride (BGAF, Dentsply Sirona USA) or fluoride alone (NUPRO White, Dentsply Sirona USA) using fluoride-Ion Selective Electrode (F-ISE), Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), 19F and 31P Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR). A thin layer (0.0674 ± 0.0005 g) of each varnish (20 × 25 mm in area) was spread on a roughened glass slide (n = 7). They were separately immersed in 10 ml Tris buffer (0.06 M, pH = 7.30), and changed after 1, 2, 4, 6, 24 and 48 h. Fluoride-ion concentration at each time using the F-ISE, whilst calcium and phosphate release were investigated using ICP-OES. XRD, FTIR. MAS-NMR analyses were also performed before and after immersion. The cumulative F-ion release was significantly higher in CPP-ACPF (1.113 mmol/g) > BGAF(0.638) > F(0.112) (p < 0.001). The cumulative calcium and phosphorus were higher in the CPP-ACPF (0.137 mmol/g, 0.119) than BGAF (0.067, 0.015) (p < 0.001) respectively. The XRD and 19F MAS-NMR confirmed the presence of NaF peaks in all cases before immersion. There were less prominent signal and appearance of fluorapatite crystals after immersion. 19F MAS-NMR revealed CaF 2 formation after immersion in both CPP-ACPF and BGAF. 31P MAS-NMR showed phosphate signals in both CPP-ACPF and BGAF before immersion. FTIR failed to show any signs of apatite formation. Both CPP-ACP and bioactive glass enhanced ion release without compromising the bioavailability of fluoride. The CPP-ACPF varnish had the most promising ion release. [ABSTRACT FROM AUTHOR]

This study investigates the potential of microalloying to control the ion release of a palladium-based metallic glass (Pd-MG). Silver and gallium are used as microalloying elements known for their antibacterial properties. Studies of ion-release kinetics, thermal and mechanical properties, formability, and corrosion behavior show that microalloying is a viable strategy to control ion release from metallic glasses. There is potential to maintain the optimal physical properties of metallic glasses while enhancing their antibacterial functionalities and biocompatibility. The study opens avenues for the development of advanced implant materials with improved mechanical strength, durability, and increased antibacterial response. [Display omitted] • Addition of up to 2 at% Ga and 4 at% Ag to 6 mm Pd 43 Cu 27 Ni 10 P 20 retain complete amorphous structure. • A palladium gallium phosphide or a silver palladium phosphide forms for higher amounts of microalloying. • Addition of Ga and/or Ag does not affect strength but substantially increases hardness in compositions with 2 at% Ga. • Concurrent microalloying with Ga and Ag reduces overall ion release more effectively than either element individually. • Microalloying metallic glass enables tuning of antibacterial ion release while retaining important properties for medical use. [ABSTRACT FROM AUTHOR]

This study highlights the effects of sintering temperature on the microstructures, densification, grain sizes/boundaries, calcium/phosphorus (Ca/P) ion ratios, mechanical and bioactive properties of biocompatible hydroxyapatite (HA) ceramics prepared via cold isostatic pressing. X-ray diffraction refinement analysis revealed that the phase ratios of hexagonal HA and secondary phases were sensitive to the sintering temperature. Grain sizes, densities, and shrinkages of the as-sintered HA ceramics increased with increasing sintering temperature. The Ca/P ratios of the as-sintered HA specimens ranged from 1.63 to 1.71 for sintering temperatures of 900–1300 °C. The maximum mechanical hardness was achieved in the specimen sintered at 1200 °C due to the dense matrix formed with a smaller grain size and fewer flawed grain boundaries, as determined by high-resolution transmission electron microscopy. Ion release analysis (in a simulated body fluid solution) indicated that phosphorus ions were absorbed and rapid deposition of calcium ions occurred after immersion periods of above 4 days. [ABSTRACT FROM AUTHOR]

The use of bioactive glasses (e.g. silicates, phosphates, borates) has demonstrated to be an effective therapy for the restoration of bone fractures, wound healing and vascularization. Their partial dissolution towards the surrounding tissue has shown to trigger positive bioactive responses, without the necessity of using growth factors or cell therapy, which reduces money-costs, side effects and increases their translation to the clinics. However, bioactive glasses often need from stabilizers (e.g. SiO 4 4−, Ti4+, Co2+, etc.) that are not highly abundant in the body and which metabolization is not fully understood. In this study, we were focused on synthesizing pure calcium phosphate glasses without the presence of such stabilizers. We combined a mixture of ethylphosphate and calcium 2-methoxyethoxide to synthesize nanoparticles with different compositions and degradability. Synthesis was followed by an in-depth nuclear magnetic resonance characterization, complemented with other techniques that helped us to correlate the chemical structure of the glasses with their physiochemical properties and reaction mechanism. After synthesis, the organically modified xerogel (i.e. calcium monoethylphosphate) was treated at 200 or 350 °C and its solubility was maintained and controlled due to the elimination of organics, increase of phosphate-calcium interactions and phosphate polycondensation. To the best of our knowledge, we are reporting the first sol-gel synthesis of binary (P 2 O 5 -CaO) calcium phosphate glass nanoparticles in terms of continuous polycondensated phosphate chains structure without the addition of extra ions. The main goal is to straightforward the synthesis, to get a safer metabolization and to modulate the bioactive ion release. Additionally, we shed light on the chemical structure, reaction mechanism and properties of calcium phosphate glasses with high calcium contents, which nowadays are poorly understood. The use of bioactive inorganic materials (i.e. bioactive ceramics, glass-ceramics and glasses) for biomedical applications is attractive due to their good integration with the host tissue without the necessity of adding exogenous cells or growth factors. In particular, degradable calcium phosphate glasses are completely resorbable, avoiding the retention in the body of the highly stable silica network of silicate glasses, and inducing a more controllable degradability than bioactive ceramics. However, most calcium phosphate glasses include the presence of stabilizers (e.g. Ti4+, Na+, Co2+), which metabolization is not fully understood and complicates their synthesis. The development of binary calcium phosphate glasses with controlled degradability reduces these limitations, offering a simple and completely metabolizable material with higher transfer to the clinics. [ABSTRACT FROM AUTHOR]

• More calcium ions were released from the new materials, more calcium bound to carboxyl groups in the matrix. • Biphasic release occurs before Fluoride recharge and monophasic release occurs after recharge. • New materials suppressed S. mutans growth and biofilm formation. • We produced cement by reinforcing the material properties of conventional GIC-based sealant. The aim of this study was to investigate the chemical and biological properties of newly developed bioactive cements, modified such that they are largely composed of calcium, phosphate and fluoride. We investigated whether newly developed bioactive cements have the potential to further protect surrounding hard tissue and enhance remineralization of demineralized tissue by additional ion release. We developed four types of novel GIC based on Fuji VII, modified with phosphate and fluoride and calcium. Compressive strength tests were performed following JIS T6607 methods. Ion release of calcium, phosphate and fluoride after 24 h storage were determined using atomic absorption spectroscopy, colorimetry and an ion-specific electrode. Fluoride releases and recharge were measured at 1, 3, 6, 12, 24 and 168 h. Viability was determined by colony-forming units. Inhibitions of biofilm formation and cell proliferation activity were measured. The GIC groups showed no significant differences in compressive strength after 1 and 7 days. The rates of fluoride ion release from newly developed GICs were significantly greater than those of Fuji VII, Fuji III and BS. All materials except TM can be recharged with fluoride ions. Compared with the control group, which did not release fluoride ions, all materials showed significantly stronger antibacterial effects. The newly developed GICs and BS showed less biofilm formation than Fuji VII and Fuji III. Three of four newly developed GICs modified with calcium, phosphate and fluoride ions were found to be superior to other sealant materials. [ABSTRACT FROM AUTHOR]

Abstract Objective The objective of this study was to establish the overall remineralizing potential of bioactive glasses which were specifically designed to be incorporated in dental varnishes. This study evaluates the in vitro ability of bioactive glasses (BAGs) to release ions including: fluoride, calcium, strontium and phosphate and to form apatite when immersed in Tris buffer solution, and also investigates the effect of increasing strontium substitution for calcium on remineralization potential. Materials and methods A melt-derived bioactive glass series was formulated (SiO 2 –Na 2 O–CaO–P 2 O 5 -CaF 2) with progressive (0–100%) replacement of calcium (Ca) with strontium (Sr) and prepared. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were utilised before and after immersion for specific time periods (0, 3, 6, 24, 72, 168 h) in 50 ml Tris buffer solution at 37 °C. A fluoride-ISE was used to measure the concentration of fluoride, whilst inductively coupled plasma–optical emission spectroscopy (ICP-OES) was used to measure the concentration of phosphorus, calcium and strontium in the solutions. Results The FTIR and XRD data indicated the amorphous nature of all unreacted bioactive glasses, except for the high Sr-substituted glasses, which crystallised to fluorapatite. Degradation of all the glass powders resulted in fluoride, phosphate and calcium/strontium ion release. All the glasses formed apatite on immersion. Ion release enhanced significantly in the three compositions with 50% SrO substituted for CaO, while calcium ion release was greater for low SrO substitutions. Conclusion Ion release data obtained for the new compositions of novel bioactive glasses to be incorporated into varnishes have promise in the prevent and/or treatment of white spot lesions through the release of fluoride, phosphate and calcium/strontium. Highlights • Mixed calcium-strontium-fluoride containing bioactive glasses form mixed calcium-strontium Fluorapatite upon immersion • High strontium for calcium substitution can lead to crystallisation of the glasses. • These glasses release calcium, strontium, phosphate and fluoride and can be used in dentistry for varnishes. [ABSTRACT FROM AUTHOR]

Abstract Monitoring and stimulating in biological systems are strongly dependent on the nature of the interfaces between biological systems and devices; in addition, one-dimensional nanostructures show high-charge accumulation at their surfaces which result in forming a conductive pathway between devices and cells. ZnO nanostructures because of their dual semiconducting properties and their piezoelectricity show a great potential to deploy in optoelectronic devices, biosensors and transducers in biological systems. For this purpose, we introduced a novel one-step hydrothermal nanowire array fabrication and compared it with ZnO nanorods array and ZnO compact film. Grazing incidence X-ray Diffraction (GIXRD), field-emission scanning electron microscope (FE-SEM), disperse X-ray spectroscopy (EDS) detector and inductively couples plasma optical emission spectrometry (ICP-OES) were used for physical and chemical characterizations of the arrays. In addition, we investigated the ability of zinc oxide nanostructures to control cell adhesion and viability of neuron-like PC12 cells. Furthermore, we examined the zinc oxide solubility and our results indicated that cytotoxicity were occurred in 2.23 ± 0.41 µg/ml concentration of zinc ions which was much less than the safe amount of zinc ions (10.23 ± 0.41 µg/ml) reported in previous studies. It is believed that ZnO dissociation behavior crucially affects cell fates even in rare amounts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag-doped micropattern surfaces produced by photolithography method. • Formation of Ag particles on the tops of pillars due to temperature-activated diffusion. • Formation of small Ag nanoparticles in areas between pillars due to sputtering of Ag. • Rate of Ag+ ion release depended on the etching depth and Ag particle distribution. • Samples demonstrated a pronounce antibacterial effect toward Escherichia coli strains. Abstract Photolithography methods offer ample opportunities for creating biological surface patterns over large areas. Herein, samples with patterned surface having the same Ag total coverage area and content, but different surface topography made of periodically spaced Ag/Si pillars with a diameter of 10 and 50 μm and a height of 3, 1, and 0.2 μm were produced by photolithography technique and studied to uncover the dependences of bactericide ion release on surface topography and antibacterial effect on Ag+ ion concentration. Reactive ion etching of Si wafers in areas unprotected by Ag capping layer was accompanied by a number of competing processes: (i) formation of Ag particles on the tops of pillars due to temperature-activated diffusion and coalescence, (ii) sputtering of Ag from the pillar to surface and redeposition into the etching cavities, resulting in the formation of small Ag nanoparticles located in areas between pillars, (iii) precipitation of AgSi x phase as a result of chemical interaction of sputtered Si ions with Ag ions and atoms in surrounding plasma. Samples with the largest pillar heights which had also Ag particles formed between pillars demonstrated the fastest Ag+ ion release and, correspondingly, a noticeable antibacterial effect toward antibiotic-resistant hospital Escherichia coli K-261 strains already after 3 h. All samples showed 100% antibacterial effect after 24 h. Thus our results open up new possibilities for the production of scalable micropattern surfaces with controlled bactericide ion release and pronounced antibacterial characteristics for future applications in the orthopedic field. [ABSTRACT FROM AUTHOR]

Polymer hydrogels crosslinked by therapeutic metal ions have attracted increased interest in recent years due to their unique and versatile properties. Chitosan hydrogels are widely investigated for various biomedical applications such as tissue engineering and drug delivery. Copper and zinc ions are considered as therapeutic metal ions, that have important roles in bone regeneration. The aim of this study was to investigate the physicochemical and biological properties of bimetallic–chitosan complex hydrogels with different cupric and zinc ions content. Scanning electron microscopy (SEM) revealed changes in the morphology from the microstructure with larger, tubular pores for aerogels with higher Zn content, to the sheets-like structure with long pores for samples with higher Cu content. FTIR analysis indicated the formation of bimetallic–chitosan aerogels. The obtained X-ray diffraction patterns showed a broadening of chitosan's characteristic diffraction maximum, while characterization of physical properties showed decreased swelling ability and increased shear modulus with higher Cu content. ICP-MS results showed a negligible amount of copper and zinc ions released under physiological conditions during 24 h indicating a strong physical crosslink between metal ions and chitosan chains. Furthermore, accelerated in vitro degradation showed that hydrogels maintained good stability during four weeks of lysozyme activity. The MTT assay indicated that the cytotoxicity of Cu2+–Zn2+/chitosan complexes could be adjusted by the amount of cupric ions. All results imply that Cu2+ and Zn2+ ions act as physical crosslinkers of the polymer network. Also, results are in agreement with the prediction of density functional theory (DFT) which indicated stronger chitosan–Cu tetrahedral aqua complex interactions in comparison to the chitosan–[Zn(H 2 O) 4 ]2+ interactions. [Display omitted] • Density functional theory indicated interactions [M(H 2 O) 4 ]2+ – amino group. • Cu–Zn/CHT physicochemical and biological properties are c (Cu)-dependent. • Cu–Zn/CHT aerogels show good stability during enzymatic degradation. • Cu2+ and Zn2+ ions served as physical crosslinkers of the chitosan chains. [ABSTRACT FROM AUTHOR]

A novel strategy to produce bi-metallic heterogeneous Cu/Ag nanoparticles using the gas aggregation source based on cylindrical post-magnetron with segmental Cu/Ag targets is introduced and investigated. It is shown that the production rate of nanoparticles depends not only on the magnetron current and aggregation pressure but also on the ratio of the Cu and Ag in the segmental target. Enhanced production of nanoparticles for larger Cu part in the segmental target has been observed. Furthermore, it is demonstrated that various types of Cu/Ag nanoparticles may be produced including dumbbell-like or onion-like ones with well-separated Cu and Ag domains. Finally, it has been for the first time confirmed that the gas-phase synthesized heterogeneous Cu/Ag nanoparticles are prone to extensive galvanic corrosion. This effect promotes the antibacterial efficiency of Cu/Ag nanoparticles compared to mono-metallic Cu ones, making such nanoparticles highly interesting for medical applications. • Post magnetron-based gas aggregation source produces the Cu/Ag nanoparticles. • Cu/Ag nanoparticles have a heterogeneous structure with well-separated domains. • Heterogeneous nanoparticles exhibit enhanced galvanic corrosion. • Cu/Ag nanoparticles are convenient for designing novel antibacterial coatings. [ABSTRACT FROM AUTHOR]

Abstract Certain biomaterials are capable of inducing the secretion of Vascular Endothelial Growth Factor (VEGF) from cells exposed to their biochemical influence, which plays a vital role in stimulating angiogenesis. Looking for this capacity, in this study three porous glasses were synthesized and characterized. Glass compositions (in mol-%) were: 60SiO 2 –(36-2x)CaO–4P 2 O 5 –xCuO–xSrO with x = 0, 1 or 2.5, respectively, for B60, CuSr-1 or CuSr-2.5 glasses. Cu2+ and Sr2+ ions were added because of the reported biological capabilities of Cu2+ as angiogenic stimulator and Sr2+ as osteogenic stimulator. The objective of this study was to determine the concentration of the glass particles that, being out of the cytotoxic range, could increase VEGF secretion. The viability of cultivated bone marrow stromal cells (ST-2) was assessed. The samples were examined with light microscopy (LM) after the histochemical staining for haematoxylin and eosin (HE). The biological activity of glasses was evaluated in terms of the influence of the Cu2+ and Sr2+ ions on the cells. The dissolution products of CuSr-1 and CuSr-2.5 produced the highest secretion of VEGF from ST-2 cells after 48 h of incubation. The combination of Cu2+ and Sr2+ lays the foundation for engineering a bioactive glass than can lead to vascularized, functional bone tissue when used in bone regeneration applications. Highlights • Mesoporous bioactive glasses containing Cu and Sr synthesized. • Cytocompatibilty of glasses studied with bone marrow stromal cell line (ST-2). • Vascular Endothelial Growth Factor secretion affected by Cu and Sr release. [ABSTRACT FROM AUTHOR]

In order to improve the osteoconductivity and the osteoinductivity of bone tissue engineering scaffold, a novel bi-phase strontium-doped magnesium phosphate/calcium silicate (Sr-MP/CSC) composite scaffold was fabricated by the self-solidifying/particulate leaching method. The bi-phase composition of the well-crystallized struvite grains wrapped by the calcium silicate floccules was propitious to the deformability and toughness of composite scaffold, and the porous structure with interconnected macropores of 100–400 µm was beneficial to supporting the tissue growth and transporting nutrients and metabolites. When the Sr-MP/CSC composite scaffolds were degraded in the simulated physiological environment, the doped strontium could be sustainably released together with Ca 2+ , Mg 2+ , PO 4 3- and silidous ions. The proliferation and osteogenic differentiation of rat bone marrow stromal cells (BMSCs) on these composite scaffolds were obviously promoted. More valuably, the Sr-doped MP/CSC scaffolds exhibited the more obvious promotion to ALP activity, Col I and OCN expression than the un-doped MP/CSC scaffold, especially in the later stage. The results suggested that the strontium combined with calcium, magnesium and silicon could synergically promote osteogenesis, and the Sr-MP/CSC composite might be one of the promising bone tissue engineering scaffold materials. [ABSTRACT FROM AUTHOR]

Tissue engineering using single-phased silicate–containing calcium phosphate bioceramic scaffolds is a promising and highly effective approach for periodontal repair, which provide an appropriate mechanical properties, proper degradation and good manufacturability. Both in vitro, and post-surgery evaluations demonstrated that they have advanced capability to stimulate osteogenesis/cementogenesis. However, the complex mechanisms of their action have not yet been clarified. It is clear that Ca 2+ , PO 4 3 - and SiO 4 4 release profile (from the scaffold) directly affect on the osteogenesis and cementogenesis. Each of these ions, alone or committed together, modulates pathways upregulation leading to cell attachment, proliferation and differentiation, apatite formation/deposition, extracellular matrix formation and mineralization. Upregulating/downregulating a pathway may impress upregulation/downregulation of another pathway, and therefore provide a cyclic procedure which may affect both the release and absorption profiles of other ions. This review article aims to discuss how the ion releases could modulate signaling pathways’ upregulation. Further, this paper will elaborate the importance of using specialized engineering methods to prevent misinterpreting of the in vitro and in vivo investigations. [ABSTRACT FROM AUTHOR]

Biomedical cements are considered promising injectable materials for bone repair and regeneration. Calcium phosphate composition sized with tens of micrometers is currently one of the major powder forms. Here we report a unique cement form made from mesoporous bioactive glass nanoparticles (BGn). The nanopowder could harden in reaction with aqueous solution at powder-to-liquid ratios as low as 0.4–0.5 ( vs . 2.0–3.0 for conventional calcium phosphate cement CPC). The cementation mechanism investigated from TEM, XRD, FT-IR, XPS, and NMR analyses was demonstrated to be the ionic (Si and Ca) dissolution and then reprecipitation to form Si-Ca-(P) based amorphous nano-islands that could network the particles. The nanopowder-derived nanocement exhibited high surface area (78.7 m 2 /g); approximately 9 times higher than conventional CPC. The immersion of nanocement in simulated body fluid produced apatite nanocrystallites with ultrafine size of 10 nm ( vs. 55 nm in CPC). The ultrafine nanocement adsorbed protein molecules (particularly positive charged proteins) at substantial levels; approximately 160 times higher than CPC. The nanocement released Si and Ca ions continuously over the test period of 2 weeks; the Si release was unique in nanocement whereas the Ca release was in a similar range to that observed in CPC. The release of ions significantly stimulated the responses of cells studied (rMSCs and HUVECs). The viability and osteogenesis of rMSCs were significantly enhanced by the nanocement ionic extracts. Furthermore, the in vitro tubular networking of HUVECs was improved by the nanocement ionic extracts. The in vivo neo-blood vessel formation in CAM model was significantly higher by the nanocement implant when compared with the CPC counterpart, implying the Si ion release might play a significant role in pro-angiogenesis. Furthermore, the early bone forming response of the nanocement, based on the implantation in a rat calvarial bone defect, demonstrated a sign of osteoinductivity along with excellent osteocondution and bone matrix formation. Although more studies remain to confirm the potential of nanocement, some of the intriguing physico-chemical properties and the biological responses reported herein support the promise of the new ‘nanopowder-based nanocement’ for hard tissue repair and regeneration. [ABSTRACT FROM AUTHOR]

In this study, a double-layer Ti (C, N) film was successfully prepared on Ti-6Al-4V alloy by a series of YAG laser irradiation in nitrogen atmosphere, aiming at improving the wear resistance. The effects of laser irradiation pass upon surface chemical composition, microstructures and hardness were investigated. The results showed that the surface chemicals were independent from laser irradiation pass, which the up layer of film was a mixture of TiN and TiC 0.3 N 0.7 , and the down layer was nitrogen-rich α-Ti. Both the surface roughness and hardness increased as raising the irradiation passes. However, surface deformation and cracks happened in the case above 3 passes’ irradiation. The wear resistance of laser modified sample by 3 passes was improved approximately by 37 times compared to the as received substrate. Moreover, the cytotoxic V ion released from laser modified sample was less than that of as received Ti-6Al-4V alloy in SBF, suggesting the potentiality of a new try to modify the sliding part of Ti-based hard tissue implants in future biomedical application. [ABSTRACT FROM AUTHOR]

The increasing number of applications in which copper oxide nanoparticles (CuO NPs) are used, may lead to potential release of CuO NPs into the environment. However, the impact of natural organic matters on the behavior and fate of CuO NPs in aquatic media is still largely unknown. In this study, the dissolution and aggregation of CuO NPs under the exposure of tannic acid (TA) were monitored over a period of 72 h, with a focus on assessing the contributions of solution pH changes and complexation reactions. Results showed that the total amount of Cu 2+ released from CuO NPs increased in the presence of TA especially at the highest TA concentration of 73.5 μmol/L. Although TA was observed to wrap around the CuO NPs, the aggregation of CuO NPs was not strongly influenced by TA and by the solution pH as investigated in this study. The kinetics of Cu 2+ release were fitted using the modified pseudo second-order model and the rate of dissolution was assessed to be highest at TA = 14.7 μmol/L. At pH = 4, the increased H + concentration was responsible for increased Cu 2+ release, whereas the complexation reaction between Cu 2+ and TA dominated at pH = 7. These findings suggested that the effects of TA on the dissolution of CuO NPs were a combination of solution pH change and complexation reaction, the relative fractions of which also depended on the solution pH. Additionally, the percentage of Cu 2+ released from the CuO NPs was found to increase upon decreasing concentrations of CuO NPs. Our work helps to further understand how and to which extent natural organic matters affect the behavior and fate of CuO NPs. [ABSTRACT FROM AUTHOR]

• Hydration and hydrolysis reaction mechanism of calcium-borate systems was elaborated. • Within 8h ageing, hydration reactions were more dominant over hydrolysis reactions. • At longer ageing times, hydration and hydrolysis reactions occurred simultaneously. • Non-bridging-oxygens in glass-ceramics and hydroxyl groups in sol-gel-glasses fostered ion release. • All glass formulations demonstrated a higher boron tetrahedral fraction post-exposure to DIW. This study investigated the effect of calcium addition on boron coordination and ion release in deionized water (DIW) of five melt-quench-derived compositions: xCaO-(100-x)B 2 O 3 (x=25, 27, 33, 38 and 48 mol%) and one sol-gel-derived 48CaO-52B 2 O 3 glass. The mechanism of hydration and hydrolysis reactions was elaborated based on ionic release and structural change pre- and post- ageing in DIW. For melt-quench-derived glasses, within 8 h ageing, the hydration reactions were more rapid than the hydrolysis reactions, resulting in solution pH increase, where ionic release was more dependent on composition than boron coordination. At longer ageing times, hydration and hydrolysis reactions occurred simultaneously, leading to solution pH stabilization, and calcium and boron release decreased with an increase in the boron tetrahedral fraction (N 4) in glasses. Non-bridging-oxygens in the melt-quench-derived 48CaO-52B 2 O 3 glass-ceramic and hydroxyl groups in the equivalent sol-gel-derived glass fostered calcium and boron release. All glass formulations demonstrated higher N 4 post DIW exposure. [ABSTRACT FROM AUTHOR]

To investigate the interrelationships among handling, degree of conversion (DC), mechanical behavior and Ca2+ release of composites containing dicalcium phosphate dihydrate (DCPD, CaHPO 4.2H 2 O), as a function of total inorganic content and DCPD: glass ratio. Twenty-one formulations (1 BisGMA: 1 TEGDMA, in mols) with inorganic fractions ranging from zero to 50 vol% and different DCPD: glass ratios were evaluated for viscosity (parallel plate rheometer, n = 3), DC (near-FTIR spectroscopy, n = 3), fracture toughness/K 1C (single-edge notched beam, n = 7–11) and 14-day Ca2+ release (inductively coupled plasma optical emission spectroscopy, n = 3). Data were analyzed by ANOVA/Tukey test (except viscosity, where Kruskal-Wallis/Dunn tests were used, α: 0.05). Viscosity and DC increased with DCPD: glass ratio among composites with the same inorganic content (p < 0.001). At inorganic fractions of 40 vol% and 50 vol%, keeping DCPD content at a maximum of 30 vol% did not compromise K 1C. Ca2+ release showed an exponential relationship with DCPD mass fraction in the formulation (R2 = 0.986). After 14 days, a maximum of 3.8% of the Ca2+ mass in the specimen was released. Formulations containing 30 vol% DCPD and 10–20 vol% glass represent the best compromise between viscosity, K 1C and Ca2+ release. Materials with 40 vol% DCPD should not be disregarded, bearing in mind that Ca2+ release will be maximized at the expense of K 1C. [Display omitted] • Formulations with 0–50 vol% particles at different DCPD:glass ratios were tested. • DCPD increased the conversion of the unfilled resin, but did not increase its K 1c. • At 20–30 vol%, the association of glass and DCPD increased composite K 1c. • At 40–50 vol%, replacing up to 30 vol% of glass by DCPD did not reduce K 1c. • After 14 days, a maximum of 3.8% of the Ca2+ in the specimen was released. [ABSTRACT FROM AUTHOR]

Eight novel silicate, phosphate and borate glass compositions (coded as NCLx, where x = 1 to 8), containing different oxides ( i.e. MgO, MnO 2 , Al 2 O 3 , CaF 2 , Fe 2 O 3 , ZnO, CuO, Cr 2 O 3 ) were designed and evaluated alongside apatite-wollastonite (used as comparison material), as potential biomaterials for bone tissue repair and regeneration. Glass frits of all the formulations were processed to have particle sizes under 53 μm, with their morphology and dimensions subsequently investigated by scanning electron microscopy (SEM). In order to establish the nature of the raw glass powders, X-ray diffraction (XRD) analysis was also performed. The sintering ability of the novel materials was determined by using hot stage microscopy (HSM). Ionic release potential was assessed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Finally, the cytotoxic effect of the novel glass powders was evaluated for different glass concentrations via a colorimetric assay, on which basis three formulations are considered promising biomaterials. [ABSTRACT FROM AUTHOR]

Direct incorporation of antimicrobial additive into the polymer matrix is a cost effective approach for the development of polymer/metal antimicrobial composites. Application of these antimicrobial composite systems for manufacturing medical devices addresses the issue of device related infections. In the present study, commercially available inorganic copper based additive, Plasticopper, was incorporated into a Polyamide 11(PA 11) matrix during the polymer processing stage. These polymer composites were evaluated for their morphological, mechanical, antimicrobial and ion release properties. Isothermal crystallisation studies showed that the copper additive acted as a nucleating agent and promoted faster crystallisation. Short term mechanical studies confirmed that the incorporation of copper has reinforcing effect on the composites with 5 and 10% copper loadings and did not adversely affect the short-term mechanical performance of the polymer composites. These composite systems were shown to be active against Escherichia coli ATCC 8739 with > 99.99% reduction in bacterial population. Corresponding ion release profiles for these composites indicated long term antimicrobial activity. [ABSTRACT FROM AUTHOR]

Antimicrobial glasses are potential candidate as an additive in powder form for many different applications which makes them practically and scientifically important. In this context, incorporation of silver, zinc and copper into the powdered soda lime glass was carried out by ion exchange treatment using single and dual ion containing mediums. Investigating the effect of dual incorporation of silver-zinc and silver-copper on the ion release ability and antimicrobial activity of the glass was the motivation of this study. Considering the chemical analysis results, incorporation of silver, zinc and copper to the glass was realized after the treatment. The amount of released silver was observed to be higher than zinc and copper in aqueous environment. Unvarying pH values indicated that antimicrobial efficacies of the glasses were merely due to the incorporated ions. Silver release was significantly reduced in dual imparted glasses compared to the single silver imparted glasses. According to the antimicrobial test results, glasses showed sufficient and controlled level of ion release also showed antimicrobial activity. It was deduced that dual incorporation of silver-zinc and silver-copper into the glass lowered the silver release which was still sufficient for effective antimicrobial activity and this contributes the long term activity. [ABSTRACT FROM AUTHOR]