Amount Of Bioactive Glass Research Articles

Water-Induced Changes in Experimental Resin Composites Functionalized with Conventional (45S5) and Customized Bioactive Glass

The aim of the study was to evaluate microhardness, mass changes during 1-year water immersion, water sorption/solubility, and calcium phosphate precipitation of experimental composites functionalized with 5–40 wt% of two types of bioactive glass (BG): 45S5 or a customized low-sodium fluoride-containing formulation. Vickers microhardness was evaluated after simulated aging (water storage and thermocycling), water sorption and solubility were tested according to ISO 4049, and calcium phosphate precipitation was studied by scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. For the composites containing BG 45S5, a significant reduction in microhardness was observed with increasing BG amount. In contrast, 5 wt% of the customized BG resulted in statistically similar microhardness to the control material, while higher BG amounts (20 and 40 wt%) resulted in a significant improvement in microhardness. Water sorption was more pronounced for composites containing BG 45S5, increasing 7-fold compared to the control material, while the corresponding increase for the customized BG was only 2-fold. Solubility increased with higher amounts of BG, with an abrupt increase at 20 and 40 wt% of BG 45S5. Calcium phosphate was precipitated by all composites with BG amounts of 10 wt% or more. The improved properties of the composites functionalized with the customized BG indicate better mechanical, chemical, and dimensional stability without compromising the potential for calcium phosphate precipitation.

Laser powder bed fusion of poly-ether-ether-ketone/bioactive glass composites: Processability, mechanical properties, and bioactivity

Poly-ether-ether-ketone (PEEK) implants fabricated by laser powder bed fusion (LPBF) are promising candidates for bone tissue engineering because of the excellent biocompatibility of the material and the ability to realize personalized bone repair. However, the weak LPBF processability and biological inertness of PEEK limit the clinical application. In this work, bioactive glass (BG) is blended into PEEK and found to improve the LPBF processability and bioactivity. The results show that PEEK/BG composite powders exhibit better LPBF processability due to the wider sintering window (48.9%–79.1% wider) and higher thermal conductivity (5.7%–23.0% higher) compared with the pure PEEK as well as the crystallization inhibition during the cold powder spreading. The melting enthalpy and thermal stability of the composite reduce when the BG content increases, thereby leading to the decrease of the optimal laser power during the LPBF process. The modulus of PEEK/BG composites ranges from 2685.82 MPa to 3729.33 MPa, which can match the modulus of human cancellous bone. The variation of lattice constant c and cell volume with the laser power of the composites all show a similar trend to the mechanical properties. BG can promote hydroxy-carbonate-apatite deposition, suggesting that BG has great potential to promote osteogenesis. By varying the amount of BG incorporated, the PEEK composite implants can be applied to different regions in the body depending on the specific clinical requirements.

Preparation of chitosan-sodium alginate/bioactive glass composite cartilage scaffolds with high cell activity and bioactivity

Chitosan-sodium alginate/bioactive glass (CSB) composite cartilage scaffold with outstanding in vitro mineralization property and cytocompatibility is synthesized by freeze drying method. The effect of bioactive glass (BG) addition on the microstructure, porosity, swelling/degradation ratio, in vitro mineralization property and cytocompatibility of CSB scaffold is investigated by the characterization techniques of SEM, XRD, FTIR and BET. Results showed that CSB composite cartilage scaffold had a three-dimensional (3D) porous structure, and both porosity and average pore size met the requirements of cartilage tissue repair. Among, the typical CSB-1.0 had the largest overall pore size and lowest compressive modulus (1.083 ± 0.002 MPa). As the amount of BG increased, pore volume and porosity of CSB scaffolds gradually decreased, and the swelling and degradation ratios gradually reduced. After immersing in SBF for 3 d, cauliflower like hydroxyapatite (HA) was formed on CSB surface, indicating that the scaffold had good in vitro mineralization property. Moreover, the introduction of BG into the composite scaffold can improve the relative cell viability of MC3T3-E1 cells, and CSB-1.0 has the strongest ability to promote the proliferation of cells. Therefore, the as-obtained CSB scaffold can be used as a strong candidate for cartilage tissue engineering scaffold to meet clinical needs.

Preparation and characterization of 3D nanocomposite scaffold from bioactive glass/β-tricalcium phosphate via Robocasting method for bone tissue engineering

In this research, a three-dimensional 45S5 bioactive glass (BG) /β-tricalcium phosphate (TCP) composite (50/50 wt.%) scaffold was prepared by the Robocasting method. For this aim, BG and TCP were synthesized via sol-gel and precipitation methods, respectively, and characterized. The scaffolds were robocast by extruding the ink composed of a proper amount of BG, TCP, and required additives, then, characterized in terms of physicochemical and biological properties. Results showed that nano BG and TCP were synthesized successfully. Scaffold characterization showed that the scaffold had a controlled and interconnected porosity (40%) that exhibited notable average mechanical strength (∼17.39MP) as well as good bioactivity and supported the attachment and the proliferation of mesenchymal stem cells and had a limited effect on the survival of these cells. According to the results, it is concluded that using the Robocasting method for preparing BG/TCP scaffold provided a 3D porous interconnected structure with notable mechanical strength

Mechanical properties of resin composites containing bioactive glass and experimental nano zinc-silica complex

Aim: Secondary caries is an important problem in dental composite restoration, and nanoparticles are commonly added to the structures of resin composites to improve their antimicrobial properties. The aim of this study is to evaluate the mechanical properties of composite materials containing bioactive glass (BAG) and an experimental nano zinc-silica (NZS) complex.
 Methodology: An experimental resin composite containing 70 wt% filler was produced and used as a control sample. This experimental resin composite was then modified by adding different amounts of BAG (10%), NZS (10%), and both BAG and NZS (10% + 10%). NZS was synthesized in situ by milling zinc and silica to nanoscale level. Compressive strength and flexural strength were investigated using a universal testing machine. Data were analyzed using one-way ANOVA and the Tukey post-hoc test.
 Results: There were no statistically significant differences in compressive strength caused by the filler amount, but statistically significant changes were found in flexural strength. Although the addition of antimicrobial agents to resin composites reduces their physical properties, this is not a clinically unacceptable limit.
 Conclusion: NZS exhibits better mechanical properties than does BAG, but both materials can be used safely in restorative materials.
 
 How to cite this article: Tunçdemir MT, Demirel MG. Mechanical properties of resin composites containing bioactive glass and experimental nano zinc-silica complex. Int Dent Res 2021;11(Suppl.1):137-42. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.21
 
 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Anti-demineralizing protective effects on enamel identified in experimental and commercial restorative materials with functional fillers

The aim of this study was to investigate whether experimental and commercial dental restorative materials with functional fillers can exert a protective anti-demineralizing effect on enamel that is not immediately adjacent to the restoration. Four experimental resin composites with bioactive glass and three commercial restorative materials were investigated. Enamel blocks were incubated in a lactic acid solution (pH = 4.0) at a standardized distance (5 mm) from cured specimens of restorative materials. The lactic acid solution was replenished every 4 days up to a total of 32 days. Surfaces of enamel blocks were periodically evaluated by Knoop microhardness measurements and scanning electron microscopy. The protective effect of restorative materials against acid was identified as enamel microhardness remaining unchanged for a certain number of 4-day acid addition cycles. Additionally, the pH of the immersion medium was measured. While enamel microhardness in the control group was maintained for 1 acid addition cycle (4 days), restorative materials postponed enamel softening for 2–5 cycles (8–20 days). The materials capable of exerting a stronger alkalizing effect provided longer-lasting enamel protection. The protective and alkalizing effects of experimental composites improved with higher amounts of bioactive glass and were better for conventional bioactive glass 45S5 compared to a fluoride-containing bioactive glass. Scanning electron micrographs evidenced the protective effect of restorative materials by showing a delayed appearance of an etching pattern on the enamel surface. A remotely-acting anti-demineralizing protective effect on enamel was identified in experimental composites functionalized with two types of bioactive glass, as well as in three commercial ion-releasing restorative materials.

Investigation of Bone Growth in Additive-Manufactured Pedicle Screw Implant by Using Ti-6Al-4V and Bioactive Glass Powder Composite

In this study, we optimized the geometry and composition of additive-manufactured pedicle screws. Metal powders of titanium-aluminum-vanadium (Ti-6Al-4V) were mixed with reactive glass-ceramic biomaterials of bioactive glass (BG) powders. To optimize the geometry of pedicle screws, we applied a novel numerical approach to proposing the optimal shape of the healing chamber to promote biological healing. We examined the geometry and composition effects of pedicle screw implants on the interfacial autologous bone attachment and bone graft incorporation through in vivo studies. The addition of an optimal amount of BG to Ti-6Al-4V leads to a lower elastic modulus of the ceramic-metal composite material, effectively reducing the stress-shielding effects. Pedicle screw implants with optimal shape design and made of the composite material of Ti-6Al-4V doped with BG fabricated through additive manufacturing exhibit greater osseointegration and a more rapid bone volume fraction during the fracture healing process 120 days after implantation, per in vivo studies.

Mechanical properties of an experimental resin based composite containing silver nanoparticles and bioactive glass.

Objective:To compare the elastic modulus, flexural strength, and hardness of an experimental resin based composite (RBC) with and without containing silver nanoparticles (AgNPs) and bioactive glass (BAG) with a commercially available RBC.Methods:This study was conducted, during the period August 2016-May 2018, at the Department of Dental Materials, Peshawar Dental College, Peshawar (Pakistan) and Department of Chemistry, University of Montreal, Canada. Test specimens made in the commercial RBC acted as Group-1 (G1). An experimental RBC containing 70 wt % filler content was synthesized. It was first used as such to prepare test specimens to act as the experimental control group (G2). This RBC was then modified by adding various amounts of BAG (5%, 10% and 15%) and a fixed amount of 0.009% AgNPs to use the so modified RBCs for preparing the test specimens to belong to three groups (G3, G4 & G5). The AgNPs had been synthesized in situ by reduction of salt during photo-polymerization. Flexural strength (FS), elastic modulus (EM) and Vickers hardness were determined using universal testing machine and hardness tester respectively. Data were analyzed using one-way ANOVA and Tukey post-hoc test.Results:Except for G3 restorations showing significantly lower mean FS value, the FS for those in the other groups were not significantly different (p>0.05). Elastic modulus of the experimental RBC restorations was though higher than those of the others but the difference was statistically insignificant (p>0.05). Reduced Vickers hardness values were documented for the restorations in the G4 and G5 compared to those in the G3 but again the difference was insignificant (p>0.05). Flexural strength and hardness values of the test specimens in the experimental RBCs were significantly lower than those made in the commercial hybrid RBC (p<0.05).Conclusion:BAG and AgNPs addition to the experimental RBC in the mentioned concentration adversely affected the tested mechanical properties.

Effects of dentin demineralization and bond-strength properties of bioactive glass containing resin adhesive

This study investigated the shear bond strength and the ability of resin adhesive containing different amounts of bioactive glass (BG) to prevent dentin demineralization. BG bonds at 30%, 40%, and 50% concentrations comprised a mixture of coupling agents modifying BG and Single Bond 2. Forty permanent premolars extracted for orthodontic treatment were randomly divided into four groups, namely, control group (BG-free), 30% BG group, 40% BG group, and 50% BG group. Composite resin and dentin were prepared into bonding specimens by using respective adhesives and then immersed in artificial saliva at pH 4 for 1 week. Changes in the pH values of the solution were measured every 24 h. The microtensile bond strength (TBS) of each specimen was examined after immersion in distilled water at 37 °C for 24 h. The TBS values of the control group, 30% BG group, 40% BG group, and 50% BG group were (27.76±0.29), (27.05±0.58), (26.95±0.69), and (25.12±0.24) MPa, respectively. The TBS of the control group was not significantly different from that of the 30% BG group (P=0.06) but significantly higher than that of the 40% BG and 50% BG groups (P=0.04 and P=0.00, respectively). In addition, TBS was significantly higher in the 30% BG and 40% BG groups than in the 50% BG group (P= 0.00 and P=0.00, respectively). The pH values of the solution increased with increasing BG content. BG bonds are useful in the prevention of dentin demineralization. However, in this study, the 30% BG group did not affect the short-term bond strength. The 50% BG group displayed the optimum ability to inhibit demineralization but showed the worst bond strength.

Bioactive glass can potentially reinforce large bone defects

Introduction: Bioactive glass (BAG) has been studied widely and seems to be a very promising biomaterial in regeneration of large bone defects and osteomyelitis treatment, because of its bone bonding and antibacterial properties[1]-[5]. Potentially, it could also mechanically reinforce large defects, thus making it suitable for load-bearing applications. However, the mechanical properties of the reconstructive layer and its dependence on BAG:bone allograft mixture composition are unknown. In this study, we measured the mechanical properties of different impacted BAG/bone graft mixtures. Then these properties were used in micro-Finite Element (FE) patient-specific models to investigate whether these mixtures could restore mechanical properties of large bone defects. Materials and Methods: Five different S53P4 BAG/bone graft mixtures were impacted in a cylindrical holder, mechanically tested in confined compression and scanned with micro-CT. From these images, the mixture was identified by its three phases: bone, glass or interface region. Micro-Finite-Element (FE) models of the composites were made using a Young’s modulus of 2.5 GPa for bone and 35 GPa for BAG. The Young’s modulus for the interface region was determined by fitting experimental and micro-FE results for the same specimens. High-Resolution peripheral quantitative CT scans of a 9 mm region of the distal tibia of seven subjects were used for studying the reinforcement potential. Micro-FE models of this region were made to determine its stiffness in the original state, with a simulated cortical defect, and after that a mixture of BAG/bone or BAG alone was simulated in the defect. Results: The confined compression tests showed a strong dependence of the Young’s modulus of the BAG/bone composite on the amount of BAG, ranging from 116.7±18.2 to 654.2±35.2 MPa. The micro-FE results could fairly reproduce these measured moduli, when using a stiffness of 25 MPa for the interface layer (R2=0.678, see Figure 1).

Nanoparticulate bioactive-glass-reinforced gellan-gum hydrogels for bone-tissue engineering

This work presents bioactive-glass-reinforced gellan-gum spongy-like hydrogels (GG-BAG) as novel hydrophilic materials for use as the scaffolding in bone-tissue engineering. The reinforcement with bioactive-glass particles resulted in an improvement to the microstructure and to the mechanical properties of the material. These mechanical properties were found to be dependent on the composition and improved with the amount of bioactive glass; however, values necessary to accommodate biomechanical loading were not achieved in this study. Nevertheless, by incorporating the bioactive-glass particles, the composite material acquired the ability to form an apatite layer when soaked in simulated body fluid. Furthermore, human-adipose-derived stem cells were able to adhere and spread within the gellan-gum, spongy-like hydrogels reinforced with the bioactive glass, and remain viable, which is an important result when considering their use in bone-tissue engineering. Thus, hydrogels based on gellan gum and bioactive glass are promising biomaterials for use either alone or with cells, and with the potential for use in osteogenic differentiation.

Mastoidectomy Cavity Obliteration with Bioactive Glass

To show that mastoid cavities with continuous infections and cleaning problems can be obliterated with bioactive glass (BG) and to present results of a pilot study for 16 operations on adults. Case series with planned data collection. Päijät-Häme Central Hospital, Finland-a single ear, nose, and throat (ENT) hospital department serving a population of 216,000. Fourteen patients had a large open radical cavity with recurrent infections. Two ears had discharge and pain after simple mastoidectomy. A re-mastoidectomy included support of the cavity skin and obliteration with BG. The mean follow-up time was 2.2 years. All ears became dry. One reoperation was needed as the fascia support to the ear canal (EC) skin was too weak, and part of the BG leaked into the EC. The ear stayed dry, and the missing BG was replaced in a reoperation. A slightly short musculoperiosteal flap supported the EC skin in 1 ear. A minor amount of BG leaked into the EC. The ear stayed dry. The aim was an ample ear canal. One ear was overfilled and required meatoplasty. Simple mastoid cavities were isolated from the middle ear and become asymptomatic. In this pilot study, BG works safely and with success as an obliteration material in problematic open radical cavities. Bioactive glass seems to tolerate chronic infection in the mastoid and prevent postoperative infections.

Mastoidectomy Cavity Obliteration with Bioactive Glass

Objective: 1) Show that mastoid cavities with continuous infections and cleaning problems can be obliterated with bioactive glass (BG). Bioactive glass S53P4 inhibits bacterial growth, turns slowly into bone, and activates new bone formation. 2) Present results of a pilot study for 16 operations on adults. Method: A prospective follow-up of mastoid obliterations started in 2007. The mean follow-up time is 1.16 years. Fourteen ears had a large open radical cavity with recurrent infections. Two ears had discharge and pain after simple mastoidectomy. A re-mastoidectomy included support of the cavity skin and obliteration with BG. Results: All ears become dry. One reoperation was needed, as the fascia support to the EC skin was too weak and part of the BG leaked into the EC. The ear stayed dry, and the missing BG was replaced in a reoperation. A slightly short musculoperiosteal flap supported the EC skin in one ear. A minor amount of BG leaked into the EC. The ear stayed dry. The aim was an ample ear canal (EC). One ear was overfilled and waits for meatoplasty. Simple mastoid cavities were isolated from the middle ear and became asymptomatic. Conclusion: BG works as obliteration material in problematic open radical cavities safely and with success. BG seems to tolerate chronic infection in the mastoid and prevent postoperative infections.

Preparation and Properties of Bioactive Composite Based on Bioactive Glass and Poly-L-Lactide

Bioactive and bioresorbable composite was fabricated based on poly-L-lactide (PLLA) and bioactive glass (average particle size: 4.24 µm) by the combination of solvent evaporation technique and hot pressing. Bioactive glass granules are distributed homogeneously in the composite. With the increasing of the amount of bioactive glass, the bending strength and shearing strength of composite decrease while the bending modulus increases. PLLA/bioactive glass composites present a typical morphology of brittle failure with a smooth fracture surface. The biocompatibility test shows that the bioactive glass existing in the composite facilitates both adhesion and proliferation of rat fibroblast on the PLLA/bioactive glass composite film.