Background: Enormous improvements in dental materials’ manufacturing for the aim of producing durable dental materials without compromising the aesthetic properties were developed. One of the approaches that fulfill this aim is the use of reinforcing glass fibers as fillers into dental materials, typically resin polymers, in order to obtain glass fiber-reinforced composites. Glass fiber-reinforced composite offered many advantages to the dental materials though some limitations were recorded in many literature. Methods: In this review, a study of the glass fibers’ types, factors affecting the properties and the properties of glass fibers reinforced materials was carried out; in addition, research papers that experimentally studied their applications in dentistry were presented. Conclusion: The success of glass fibers reinforced composites in dentistry depends on glass fibers’ composition, orientation, distribution, amount, length and adhesion; these factors once employed according to the required clinical situation would provide the essential reinforcement to the dental restorations and appliances.
19 March 2018 in Journal of Biomaterials Applications
Nanofibrillated cellulose, obtained from rice straw agricultural wastes was used as a substrate for the preparation of a new injectable and mineralized hydrogel for bone regeneration. Tetramethyl pyridine oxyl (TEMPO) oxidized nanofibrillated cellulose, was mineralized through the incorporation of a prepared and characterized biphasic calcium phosphate at a fixed ratio of 50 wt%. The TEMPO-oxidized rice straw nanofibrillated cellulose was characterized using transmission electron microscopy, Fourier transform infrared, and carboxylic content determination. The injectability and viscosity of the prepared hydrogel were evaluated using universal testing machine and rheometer testing, respectively. Cytotoxicity and alkaline phosphatase level tests on osteoblast like-cells for in vitro assessment of the biocompatibility were investigated. Results revealed that the isolated rice straw nanofibrillated cellulose is a nanocomposite of the cellulose nanofibers and silica nanoparticles. Rheological properties of the tested materials are suitable for use as injectable material and of nontoxic effect on osteoblast-like cells, as revealed by the positive alkaline phosphate assay. However, nanofibrillated cellulose/ biphasic calcium phosphate hydrogel showed higher cytotoxicity and lower bioactivity test results when compared to that of nanofibrillated cellulose.
Objective This article evaluates the antibacterial and remineralization potential of experimentally prepared toothpastes containing different mixtures of nano casein phosphopeptides (nCPP), nano amorphous calcium phosphate (nACP), probiotic Lactobacillus rhamnosus B-445 (L. rhamnosus), and nano glycomacropeptide (nGMP). Materials and Methods Five experimental toothpaste samples were prepared and grouped, such that group (A0) was the experimental toothpaste base formula. Groups (A1), (A2), (A3), and (A4) were the experimental toothpastes containing: nCPP; nCPP and nACP; nCPP, nACP, and L. rhamnosus, and nCPP, nACP, and nGMP, respectively. Group (A5) was the commercial group (GC MI Paste Plus). The five groups were screened against Streptococcus mutans (ATCC 25175) growth, and investigated for their remineralizing potentials on demineralized bovine enamel using Vickers microhardness test (Vickers hardness number [VHN]). Scanning electron microscope (SEM) images were obtained for the demineralized and remineralized enamel of the two most effective toothpastes against in vitro bacterial induced enamel demineralization. Statistical analysis was performed using one-way analysis of variance (ANOVA) as well as repeated measures ANOVA followed by Tukey’s post hoc test. Results Both (A3) and (A4) were significantly higher in mean inhibition zone diameters than group (A1) and (A2). Group (A4) showed the highest statistical significance in the mean difference between VHN values of demineralization and 15 days remineralization period. SEM images showed the deposition of nano-sized particles fill the microrough surface pattern of the etched enamel. Conclusion All these findings suggest the use of probiotic, nCPP–nACP, and nGMP as a dental anticariogenic and remineralizing active agents.
1 December 2018 in Materials Science and Engineering: C
In this research, Mg–3Zn–xSi (x = 0, 0.1, 0.3, and 0.6 wt%) biodegradable alloys were produced by simple stir casting method, their microstructure and phase changes were evaluated using X-ray diffraction (XRD), optical microscope (OM) and scanning electron microscope coupled with energy dispersive x-ray analysis (SEM–EDS). Potentiodynamic polarization was conducted to measure the alloys’ corrosion behavior in simulated body fluid (SBF). Tensile strength test and in-vitro biocompatibility evaluation regarding MTT cytotoxicity, ALP osseointegration assay and MG-63 cell growth pattern were conducted. Electrochemical investigations showed that Mg–3Zn alloys enclosing Si attained degradation rates suitable for structural support until bone healing, while the Mg–3Zn alloy without Si had a corrosion rate of 0.128 mm/year which is much lower than the required value. None of the inspected alloys exhibited a significant cytotoxic effect, meanwhile, Mg–Zn base alloy and the alloy with 0.3 wt% Si demonstrated the highest ALP level. The optimum cell growth pattern was demonstrated for Mg–Zn base alloy and the alloy with 0.1 wt% Si. Evidence of calcium phosphate precipitation was observed in the four investigated Mg–3Zn alloys. Therefore, based on the fore mentioned results, Mg–3Zn–xSi alloys were suggested as viable biodegradable materials due to their compatible degradation rates, proved cytocompatibility, high cell viability and excellent osseointegration potential.