Bioglass Research Articles

Evaluation of ‘surgery-friendly’ bone scaffold characteristics: 3D printed ductile BG/PCL scaffold with high inorganic content to repair critical bone defects

The repair of irregular and complex critical bone defects remains a challenge in clinical practice. The application of 3D-printed bioceramics particle/polymer composite scaffolds in bone tissue engineering has been widely studied. At present, the inorganic particle content of the composite scaffolds is generally low, resulting in poor osteogenic activity. However, scaffold with high inorganic content are highly brittle, difficult to operate during surgery, and cannot be in close contact with surrounding bones. Therefore, it is of great significance to design a ‘surgery-friendly’ scaffold with high bioceramic content and good ductility. In this study, we used the solvent method to add high concentration (wt% 70%) bioglass (BG) into polycaprolactone (PCL), and polyethylene glycol was used as plasticizer to prepare 70% BG/PCL composite scaffolds with high ductility using 3D printing technology. In vitro experiments showed that the scaffold had good mechanical properties: easy extension, easy folding and strong compressive resistance. It also showed good performance in biocompatibility and osteogenic activity. It was further observed that compared with pure BG or PCL implantation, the scaffold with higher BG content could have more new bone tissue appeared after 12 weeks. All these results indicate that 3D-printed 70% BG/PCL scaffolds have great potential for personalized repair of bone defects.

Nanostructured Ag‐Bioglass Implant Coatings with Antibacterial and Osteogenic Activity

AbstractBone implant failure due to aseptic loosening and biofilm infections is an increasing healthcare problem. Implants may be coated with nanoparticles to avoid bacterial colonization and promote osseointegration. However, these nanocoatings often require long, expensive, and complex manufacturing routes with limited clinical translation potential. Here, a multifunctional nanoparticle coating consisting of silver (Ag) and bioglass (BG) is investigated to overcome current limitations by providing synchronously antibacterial and osteogenic effect. Flame spray pyrolysis (FSP) is exploited as a scalable and reproducible process to synthesize large quantities of nanoparticles and deposit them on titanium (Ti) substrates. The deposited nanocoatings show a homogeneous morphology and biomineralize after soaking in simulated body fluid (SBF), while their adhesion on Ti substrates is promoted by in situ flame annealing. The Ag+ ion release from Ag containing BG samples inhibits Staphylococcus aureus biofilm formation up to 3 log units, while the osteogenic responses of pre‐osteoblastic cells directly grown on AgBG samples show similar levels of alkaline phosphatase activity, calcium and collagen production when compared to pure Ti. The inexpensively synthesized multifunctional AgBG nanostructured implant coatings exert a high bioactivity and antibacterial response while maintaining high biocompatibility. The insights of this study can direct the development of multifunctional implant coatings.

The effect of fluxing agents and heat treatment on the leucite crystallization in bio glass–ceramic composites

The effect of fluxing agents and heat treatment on the leucite crystallization in bio glass–ceramic composites

Design and characterization of bio-elastomers containing biomaterials for tissue engineering application

AimsThe purpose of this research is to fabricate a new type of bio-elastomer based on Poly(glycerol-sebacate)-co-Poly(hydroxybutyrate) (PGS-co-PHB) with varying amounts of bioglass 45S5 (BG) nanoparticles (1, 3 and 5 wt%) through the green polycondensation polymerization for tissue engineering applications. Materials and methodsFabricated composite films are characterized by FTIR, 1H NMR, SEM, EDX, contact angle, DMTA, biodegradability, and biocompatibility. The cell viability and morphology of L929 cells are investigated by indirect MTT assay and SEM analysis, and the antibacterial activity of composite film is determined by the disk diffusion method. Furthermore, the bioactivity of the composite film is measured by soaking in simulated body fluid (SBF), and XRD and SEM determined the formation of a hydroxyapatite (HA) layer. Key findingsThe hydrophilicity improved by adding BG nanoparticles, and the water contact angle was reduced to 63.46°. Furthermore, the average cell viability of composite film is about 94 %, and the SEM images show that L929 fibroblast cells are well spread on the surface of the composite film. BG has a significant influence on the antibacterial activity of composite film as PGS-co-PHB/5 %BG shows more antibacterial properties due to the higher amount of BG. SEM and XRD analyses confirmed the presence of crystalline HA on the surfaces of the composite film, indicating their potential for high bioactivity. SignificanceThe results indicate that the antibacterial composite films are excellent supports for cell growth and proliferation and could be promising candidates for tissue engineering applications.

Current Development in Biomaterials-Hydroxyapatite and Bioglass for Applications in Biomedical Field: A Review.

Inorganic biomaterials, including different types of metals and ceramics are widely used in various fields due to their biocompatibility, bioactivity, and bioresorbable capacity. In recent years, biomaterials have been used in biomedical and biological applications. Calcium phosphate (CaPs) compounds are gaining importance in the field of biomaterials used as a standalone material or in more complex structures, especially for bone substitutes and drug delivery systems. The use of multiple dopants into the structure of CaPs compounds can significantly improve their in vivo and in vitro activity. Among the general information included in the Introduction section, in the first section of this review paper, the authors provided a background on the development of hydroxyapatite, methods of synthesis, and its applications. The advantages of using different ions and co-ions for substitution into the hydroxyapatite lattice and their influence on physicochemical, antibacterial, and biological properties of hydroxyapatite are also presented in this section of the review paper. Larry Hench's 45S5 Bioglass®, commercially named 45S5, was the first bioactive glass that revealed a chemical bond with bone, highlighting the potential of this biomaterial to be widely used in biomedicine for bone regeneration. The second section of this article is focused on the development and current products based on 45S5 Bioglass®, covering the historical evolution, importance of the sintering method, hybrid bioglass composites, and applications. To overcome the limitations of the original biomaterials, studies were performed to combine hydroxyapatite and 45S5 Bioglass® into new composites used for their high bioactivity and improved properties. This particular type of combined hydroxyapatite/bioglass biomaterial is discussed in the last section of this review paper.

Resin-modified glass ionomer enriched with BIOGLASS: Ion-release, bioactivity and antibacterial effect.

Developing dental materials for the prevention of remineralization or demineralization is important for high-risk caries patients. This study aimed to evaluate the physicochemical and microbiological effects of adding 45S5 bioglass to resin-modified glass ionomer cement (RMGIC). Samples belonged to the following groups: GIC: conventional glass ionomer cement (Vitro Fil), RMGIC: resin-modified GIC (Vitro Fil LC), and RMGIC/45S5: RMGIC with 10% (wt%) of 45S5. Changes in pH and release of fluoride, calcium, and phosphorus ions under acidic (pH4) and neutral (pH7) pH conditions were evaluated. Antibacterial activity was verified based on colony-forming units. Material sorption and solubility were analyzed after bacterial exposure. After 28 days, the bioactivity of the materials was evaluated using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Analysis of variance, post hoc Scheffe, and Tukey (α=0.05) tests were employed for statistical analysis. RMGIC/45S5 showed higher alkalization activity, calcium release at pH4 and 7, and sorption than GIC and RMGIC (p < .05). Release of phosphorus and fluoride at pH4 and 7 was higher for GIC than that for RMGIC and RMGIC/45S5 (p < .05). RMGIC/45S5 showed higher values than RMGIC (p < .05). However, antibacterial activity did not differ among the groups. Precipitates of calcium and phosphorus were visualized in RMGIC/45S5 samples via SEM/EDS. These results indicate that the RMGIC/45S5 promotes alkalization and increases the release of calcium, phosphorus, and fluoride ions, resulting in precipitate deposition rich in calcium and phosphorus, thereby being a promising option to improve the bioactivity of RMGIC.

3D Biocomposites Comprising Marine Collagen and Silica-Based Materials Inspired on the Composition of Marine Sponge Skeletons Envisaging Bone Tissue Regeneration.

Ocean resources are a priceless repository of unique species and bioactive compounds with denouement properties that can be used in the fabrication of advanced biomaterials as new templates for supporting the cell culture envisaging tissue engineering approaches. The collagen of marine origin can be sustainably isolated from the underrated fish processing industry by-products, while silica and related materials can be found in the spicules of marine sponges and diatoms frustules. Aiming to address the potential of biomaterials composed from marine collagen and silica-based materials in the context of bone regeneration, four different 3D porous structure formulations (COL, COL:BG, COL:D.E, and COL:BS) were fabricated by freeze-drying. The skins of Atlantic cod (Gadus morhua) were used as raw materials for the collagen (COL) isolation, which was successfully characterized by SDS-PAGE, FTIR, CD, and amino acid analyses, and identified as a type I collagen, produced with a 1.5% yield and a preserved characteristic triple helix conformation. Bioactive glass 45S5 bioglass® (BG), diatomaceous earth (D.E.) powder, and biosilica (BS) isolated from the Axinella infundibuliformis sponge were chosen as silica-based materials, which were obtained as microparticles and characterized by distinct morphological features. The biomaterials revealed microporous structures, showing a porosity higher than 85%, a mean pore size range of 138-315 μm depending on their composition, with 70% interconnectivity which can be favorable for cell migration and ensure the needed nutrient supply. In vitro, biological assays were conducted by culturing L929 fibroblast-like cells, which confirmed not only the non-toxic nature of the developed biomaterials but also their capability to support cell adhesion and proliferation, particularly the COL:BS biomaterials, as observed by calcein-AM staining upon seven days of culture. Moreover, phalloidin and DAPI staining revealed well-spread cells, populating the entire construct. This study established marine collagen/silica biocomposites as potential scaffolds for tissue engineering, setting the basis for future studies, particularly envisaging the regeneration of non-load-bearing bone tissues.

Finite Element-Based Machine Learning Model for Predicting the Mechanical Properties of Composite Hydrogels

In this study, a finite element (FE)-based machine learning model was developed to predict the mechanical properties of bioglass (BG)-collagen (COL) composite hydrogels. Based on the experimental observation of BG-COL composite hydrogels with scanning electron microscope, 2000 microstructural images with randomly distributed BG particles were created. The BG particles have diameters ranging from 0.5 µm to 1.5 µm and a volume fraction from 17% to 59%. FE simulations of tensile testing were performed for calculating the Young’s modulus and Poisson’s ratio of 2000 microstructures. The microstructural images and the calculated Young’s modulus and Poisson’s ratio by FE simulation were used for training and testing a convolutional neural network regression model. Results showed that the network developed in this work can effectively predict the mechanical properties of the composite hydrogels. The R-squared values were 95% and 83% for Young’s modulus and Poisson’s ratio, respectively. This work provides a surrogate model of finite element analysis to predict mechanical properties of BG-COL hydrogel using microstructure images, which could be further utilized for characterizing heterogeneous materials in big data-driven material designs.

The Design of 3D-Printed Polylactic Acid-Bioglass Composite Scaffold: A Potential Implant Material for Bone Tissue Engineering.

Bio-based and patient-specific three-dimensional (3D) scaffolds can present next generation strategies for bone tissue engineering (BTE) to treat critical bone size defects. In the present study, a composite filament of poly lactic acid (PLA) and 45S5 bioglass (BG) were used to 3D print scaffolds intended for bone tissue regeneration. The thermally induced phase separation (TIPS) technique was used to produce composite spheres that were extruded into a continuous filament to 3D print a variety of composite scaffolds. These scaffolds were analyzed for their macro- and microstructures, mechanical properties, in vitro cytotoxicity and in vivo biocompatibility. The results show that the BG particles were homogeneously distributed within the PLA matrix and contributed to an 80% increase in the mechanical strength of the scaffolds. The in vitro cytotoxicity analysis of PLA-BG scaffolds using L929 mouse fibroblast cells confirmed their biocompatibility. During the in vivo studies, the population of the cells showed an elevated level of macrophages and active fibroblasts that are involved in collagen extracellular matrix synthesis. This study demonstrates successful processing of PLA-BG 3D-printed composite scaffolds and their potential as an implant material with a tunable pore structure and mechanical properties for regenerative bone tissue engineering.

Bioactivity and Mechanical Properties Characterization of Bioactive Glass Incorporated with Graphene Oxide

In this study, the bioactivity and the mechanical properties (Mechanical compressive strength, Hardness, and density) of bioglass (BG) and bioglass/graphene oxide (BG/GO) were investigated. Bioglass in chemical composition [60SiO2_35CaO_5P2O5] was prepared via the sol–gel method. GO was added to the bioglass (BG) with different contents (0.5, 1, 2, and 3) wt.% named as 0.5%GO, 1%GO, 2%GO, and 3%GO samples respectively. The synthesized specimens were characterized by several techniques Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Compressive strength, Hardness, and density were studied also by different techniques to obtain the optimum Mechanical samples. The biological activity was studied by an in-vitro test in simulated body fluid (SBF) for 33 days. Results showed that: the 0.5%GO sample exhibited optimum mechanical compressive strength by approximately 82% compared to the BG sample. Hardness was increased from 0.5%GO sample up to 1%GO sample compared to BG sample and gradually decreased in 2%GO Sample and 3%GO. Bioactivity results showed deposition of HA layer on the bioglass surface and there was no significant change in it with the addition of graphene oxide.

Preparation and Characterization of 3D Printed Porous 45S5 Bioglass Bioceramic for Bone Tissue Engineering Application.

Three-dimensional (3D) printing technology provides advanced technical support for designing personalized bone tissue engineering scaffold. In this study, two porous diffusing models, namely, average and layered perforated cylindrical scaffolds, were designed for bone tissue engineering scaffold. The designed models were fabricated by liquid crystal display mask stereolithography printing. Structural design and finite element mechanical analysis were conducted. 45S5 bioglass was selected as the raw material for preparing the printing inks for bone tissue engineering scaffolds. By adjusting the viscosity and temperature of the slurry, the maximum proportion of 45S5 bioglass (40 wt%) was added into the photosensitive resin for preparing 3D printing slurry. Our results indicated that an optimized sintering condition includes the debinding rate (0.5°C/min), and temperature raising rate (5°C/min) and sintering temperature (1100°C) were proposed to sinter 45S5 bioceramic scaffolds. The amorphous 45S5 bioglass showed good crystallization after sintering, and the scaffold porous structure showed good integrity. Micropores were observed in the struts which interconnected with each other. Moreover, the porosities were tested as 57% and 45% with a uniform pore distribution. The shrinkage rate was about 10% during sintering process due to binder burning and crystallization shrinkage. The compressive strength of the sintered scaffold was 0.71 ± 0.048 MPa and 2.13 ± 0.054 MPa, respectively, which are consistent with the finite element mechanical analysis simulation results. In conclusion, the layered perforated 45S5 bioglass scaffold shows good mechanical properties and porosity, indicating that it could be a promising candidate for bone tissue engineering.

A novel borate-based 45S5 Bioglass®: In vitro assessment in phosphate-buffered saline solution

A novel borate-based 45S5 Bioglass® has been formulated and synthesized using the melt-quenching method. The in vitro assessment was performed to determine the bioactivity of the glasses using phosphate buffer saline (PBS) as an immersion solution. The pH measurement is performed using a pH meter, while ion dissolution is quantified using Inductively coupled plasma atomic emission spectrometer (ICP-OES). The immersion of borate-containing glass exhibits pH closes to human body fluid (≈7.40). The (Ca/P) atomic ratio was calculated and its value increased (1.7–4.0) along with borate contents, indicating improved bioactivity. The alteration of glass structure after the in vitro test is inspected using attenuated total reflectance sensor–Fourier transform infrared spectrophotometer (ATR-FTIR) and Raman spectrometer. The 45S5 Bioglass that comprised 40–80% of borate showed the appearance of HPO42− a vibration band which specifies the growth of hydroxyapatite (HPA) after the in vitro test. Relative to 45S5 Bioglass®, glass labeled 0.4B2O3 displayed the highest potential of HPA growth (248%), while dissolving BO3 and BO4 units at 57.36 and 8.48%, respectively. The new formulation technique offers an alternative path to control the degradation behavior of 45S5 Bioglass® glass by modifying the ratio of borate constituent. The prepared glass may find its potential in soft-bone tissue engineering applications.

In vitro Evaluation of a 20% Bioglass-Containing 3D printable PLA Composite for Bone Tissue Engineering.

Three-dimensional (3D) printing is considered a key technology in the production of customized scaffolds for bone tissue engineering. In a previous work, we developed a 3D printable, osteoconductive, hierarchical organized scaffold system. The scaffold material should be osteoinductive. Polylactic acid (PLA) (polymer)/Bioglass (BG) (mineral/ion source) composite materials are promising. Previous studies of PLA/BG composites never exceed BG fractions of 10%, as increase of bioactive BG component negatively affects the printability of the composite material. Here, we test a novel, 3D printable PLA/BG composite with BG fractions up to 20% for its biological activity in vitro. PLA/BG filaments suitable for microstructure 3D printing were spun and the effect of different BG contents (5%, 10%, and 20%) in this material on mesenchymal stem cell (MSC) activity was tested in vitro. Our results showed that all tested composites are biocompatible. MSC cell adherence and metabolic activity increase with increasing BG content. The presence of BG component in scaffold has only slight effect on osteogenic gene expression, but it has significant suppressive effect on the expression of inflammatory genes in MSC. In addition, the material did not provoke any significant inflammatory response in whole-blood stimulation assay. The results show that by increasing the BG content, the bioactivity can be further enhanced.

Electrospun polylactic acid scaffolds with strontium- and cobalt-doped bioglass for potential use in bone tissue engineering applications.

The development of nanoscale biomaterials associated with polymers has been growing over the years, due to their important structural characteristics for applications in biological systems. The present study aimed to produce and test polymeric scaffolds composed of polylactic acid (PLA) fibers associated with a 58S bioglass doped with therapeutic ions for use in tissue engineering. Three 58S Bioglass was obtained by the sol-gel route, pure and doped with 5% strontium and cobalt ions. Solutions of 7% PLA was used as control and added the three different bioglass, 4% of 58S bioglass (PLA-BG), 4% bioglass-doped strontium (PLA-BGSr) and 4% bioglass-doped cobalt (PLA-BGCo). Scaffolds were produced through electrospinning process, and was characterized chemical and morphologically. The in vitro tests were performed using mesenchymal cells cultures from femurs of nine rats, grown in osteogenic supplemented total culture medium. After osteoblastic differentiation induction cell viability, alkaline phosphatase activity, total protein content quantification, and visualization of mineralization nodule tests were performed. Analysis of normal distribution used the Shapiro-Wilk test (nanofibers diameter and biological assay). Data were compared using the Kruskal-Wallis nonparametric test (p= 0.05). The bioglasses produced proved to be free of nitrate, chlorinated and nano-sized, with effective incorporation of therapeutic ions in their structure. All materials showed cell viability (>70%), total protein production, and alkaline phosphatase activity. It was possible to develop polylactic acid scaffolds associated with 58S bioglass doped with therapeutic ions without cytotoxicity. Scaffolds characteristics appear to sustain its application in bone tissue engineering.

Polycaprolactone/chlorinated bioglass scaffolds doped with Mg and Li ions: Morphological, physicochemical, and biological analysis.

The objective was to synthesize and characterize fine polycaprolactone (PCL) fibers associated with a new 58S bioglass obtained by the precipitated sol-gel route, produced by the electrospinning process in order to incorporate therapeutic ions (Mg and Li). In PCL/acetone solutions were added 7% pure bioglass, bioglass doped with Mg(NO3 )2 and Li2 CO3 and were subjected to electrospinning process. The fibers obtained were characterized morphologically, chemically and biologically. The results showed the presence of fine fibers at the nanometric scale and with diameters ranging from 0.67 to 1.92 μm among groups. Groups containing bioglass showed particles both inside and on the surface of the fibers. The components of the polymer, bioglass and therapeutic ions were present in the fibers produced. The produced fibers showed cell viability and induced the formation of mineralization nodules. It was observed the applicability of that methodology in making an improved biomaterial, which adds the osteoinductive properties of the bioglass to PCL and to those of therapeutic ions, applicable to guided bone regeneration.

Effect of lithium doping on the glass transition behavior of the Bioglass 45S5

Differential scanning calorimetry, thermomechanical analysis and Raman spectroscopy were used to study the role of the Li2O and P2O5 oxides on the structural relaxation phenomena in the Li-doped 45S5 Bioglass. The glass transition behavior was found to be similar for the enthalpy and volume manifestations of the relaxation motions. The Tool-Narayanaswamy-Moynihan (TNM) model was applied. An improved simulation-comparative methodology was used to determine the model relaxation parameters. The TNM model parameters and the selected glass transition characteristics (the glass transition temperature and the coefficients of thermal expansion) showed no statistically significant correlation with the particular elements present in the synthesized glasses. Hence, the information about the glasses composition was used to calculate the theoretical amounts of the QnSi species in the Li-doped 45S5 glasses. It was found that practically all explored physico-chemical quantities related to the glass transition kinetics show a correlation with the content of Q2Si species that are responsible for the formation of the chain-like structures in the present glasses.

Functionally integrated bioglass microspheres-composited double-network hydrogel with good tissue adhesion and electrical conductivity for efficient wound treatment and health detection

Hydrogel dressings have been used as an important way to maintain the moist environment of the wound and accelerate healing process. The development of double-network hydrogels with both high tissue adhesion and high biosafety for wound closure and wound healing remains an ongoing challenge. Therefore, a unique double-network xanthan gum (XG)/dopamine-modified oxidized sodium alginate (OSA-DA) composite hydrogel was prepared by a facile and rapid method, in which XG network was formed by hydrogen bonding, and Ca ions released from bioglass (BG) chelated with the carboxyl group of OSA to form the second network. The prepared injectable hydrogels had good self-healing properties, biosafety and tissue adhesion. The Si ions released from BG and fucoidan loaded in the hydrogels acted together to promote the reconstruction of blood ves·sels, collagen matrix and hair follicles. The ions in hydrogels gave the hydrogel good electrical conductivity. This hydrogel also enabled functional integration and could be used as a flexible electronic skin sensor that could monitor larger movements of the elbow or fingers and track small movements of facial expressions, vocalizations and pulses in real time.

Numerical study on the influence of process parameters in direct ink writing of high viscosity bio-inks

This study uses a computational fluid dynamics model to investigate the effect of direct ink writing process parameters on the quality of 3D-printed sedimentary materials. The numerical simulation employs the level-set method of the two-phase flow module of COMSOL Multiphysics software. The selected bio-ink consists of the powder portion (45s5 bio-glass and β-TCP nanoparticles) and the polymer portion (polyvinyl alcohol), which has applications in constructing biological bone scaffolds. First, the empirical results validate the extrudate shape obtained from numerical simulation. According to the observations, increasing the inlet velocity from 15 mm/s increased the extruded ink distortion, and finally, at 50 mm/s, the distortion reached its maximum. Secondly, after calibration and validation results, the role of the most common nozzles with different diameters and input speeds on the maximum ink output velocity of the nozzle is predicted. Finally, the influence of the two dimensionless parameters (the ratio of the distance between nozzle and bed to nozzle diameter and the ratio of inlet ink velocity to print speed) on the adhesion and shape of the printed layers is examined. At distances greater than 1.5 times the diameter of the nozzle, when the extrusion speed is greater (more than 1.5 times) relative to the linear speed of the nozzle, the printed filament becomes uneven. Reducing the speed ratio between 1× and 1.5× prevents the printed filament from sticking to the substrate or causing distortion.

Strontium doped bioglass incorporated hydrogel-based scaffold for amplified bone tissue regeneration

Repairing of large bone injuries is an important problem in bone regeneration field. Thus, developing new therapeutic approaches such as tissue engineering using 3D scaffolds is necessary. Incorporation of some bioactive materials and trace elements can improve scaffold properties. We made chitosan/alginate/strontium-doped bioglass composite scaffolds with optimized properties for bone tissue engineering. Bioglass (BG) and Sr-doped bioglasses (Sr-BG) were synthesized using Sol–Gel method. Alginate-Chitosan (Alg/Cs) scaffold and scaffolds containing different ratio (10%, 20% and 30%) of BG (Alg/Cs/BG10, 20, 30) or Sr-BG (Alg/Cs/Sr-BG10, 20, 30) were fabricated using freeze drying method. Characterization of bioglasses/scaffolds was done using zeta sizer, FTIR, XRD, (FE) SEM and EDS. Also, mechanical strength, antibacterial effect degradation and swelling profile of scaffolds were evaluated. Bone differentiation efficiency and viability of MSCs on scaffolds were determined by Alizarin Red, ALP and MTT methods. Cell toxicity and antibacterial effect of bioglasses were determined using MTT, MIC and MBC methods. Incorporation of BG into Alg/Cs scaffolds amplified biomineralization and mechanical properties along with improved swelling ratio, degradation profile and cell differentiation. Mechanical strength and cell differentiation efficiency of Alg/Cs/BG20 scaffold was considerably higher than scaffolds with lower or higher BG concentrations. Alg/Cs/Sr-BG scaffolds had higher mechanical stability and more differentiation efficiency in comparison with Alg/Cs and Alg/Cs/BG scaffolds. Also, Mechanical strength and cell differentiation efficiency of Alg/Cs/Sr-BG20 scaffold was considerably higher than scaffolds with various Sr-BG concentrations. Biomineralization of Alg/Cs/BG scaffolds slightly was higher than Alg/Cs/Sr-BG scaffolds. Overall, we concluded that Alg/Cs/Sr-BG20 scaffolds are more suitable for repairing bone major injuries.

Effect of air-abrasion pretreatment with three bioactive materials on enamel susceptibility to erosion by artificial gastric juice

ObjectiveThe purpose of the study was to investigate the protective effect of three in-office preventive treatments with bioactive materials against enamel erosion induced by artificial gastric juice similar to that found in gastroesophageal reflux disease (GERD) patients. The treatments included air-abrasion of enamel with a fluoride-containing bioactive glass (BioMinF®), Bioglass 45S5 (ProSylc) and nano-hydroxyapatite (MI Pearls) to test enamel susceptibility following an erosive challenge. MethodsEnamel surface loss was evaluated using confocal microscopy, while changes in enamel surface roughness and morphology were also investigated after the treatments. SEM and EDS were used to observe formation of apatite crystals on enamel and to detect alterations in mineral composition. In Group 1 (negative control) the specimens did not receive any treatment; Group 2 specimens (positive control) treated with 0.4 % SnF2, while in Groups 3–5 enamel was air-abraded with BioMinF®, ProSylc and MI Pearls, respectively. ResultsAll the experimental groups reduced significantly enamel surface loss compared to the negative control group (p < 0.05), except for the MI Pearls treatment (p > 0.05). The most protective behavior against erosion presented the treatment with SnF2. BioMinF induced the larger amount of apatite crystals on the enamel surface, followed by ProSylc. SignificanceBioMinF and ProSylc treatments may be beneficial against dental erosion induced by gastric juice in GERD patients, while MI Pearls treatment may not suitable for this indication. Both materials promote formation of apatite crystals on enamel in acidic conditions protecting the surface from the erosion. The tested treatments may be useful in GERD patients who cannot comply with at-home therapies with SnF2.