Improved Flexural Properties of Experimental Resin Composites Functionalized with a Customized Low-Sodium Bioactive Glass

Abstract

This study evaluated the flexural properties of an experimental composite series functionalized with 5–40 wt% of a low-Na F-containing bioactive glass (F-series) and compared it to another experimental composite series containing the same amounts of the conventional bioactive glass 45S5 (C-series). Flexural strength and modulus were evaluated using a three-point bending test. Degree of conversion was measured using Fourier-transform infrared spectroscopy. Weibull analysis was performed to evaluate material reliability. The control material with 0 wt% of bioactive glass demonstrated flexural strength values of 105.1–126.8 MPa). In the C-series, flexural strength ranged between 17.1 and 121.5 MPa and was considerably more diminished by the increasing amounts of bioactive glass than flexural strength in the F-series (83.8–130.2 MPa). Analogously, flexural modulus in the C-series (0.56–6.66 GPa) was more reduced by the increase in bioactive glass amount than in the F-series (5.24–7.56 GPa). The ISO-recommended “minimum acceptable” flexural strength for restorative resin composites of 80 MPa was achieved for all materials in the F-series, while in the C-series, the materials with higher bioactive glass amounts (20 and 40 wt%) failed to meet the requirement of 80 MPa. The degree of conversion in the F-series was statistically similar or higher compared to that of the control composite with no bioactive glass, while the C-series showed a declining degree of conversion with increasing bioactive glass amounts. In summary, the negative effect of the addition of bioactive glass on mechanical properties was notably less pronounced for the customized bioactive glass than for the bioactive glass 45S5; additionally, mechanical properties of the composites functionalized with the customized bioactive glass were significantly less diminished by artificial aging. Hence, the customized bioactive glass investigated in the present study represents a promising candidate for functionalizing ion-releasing resin composites.

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

“…Instead, the improvement is likely caused indirectly due to the ability of the customized BG to improve the degree of conversion of the polymer matrix compared to the Control material. This aspect was investigated in a previous study, which showed that the degree of conversion was reduced from 67.4% measured for the Control composite to 63.7% when 40 wt% BG 45S5 was added but improved to 71.6% when 40 wt% of the customized BG was added [ 20 ]. In that study, [ 20 ], an improved degree of conversion resulted in improved macro-mechanical properties (flexural strength and modulus), while in the present study, an analogous effect was observed on micromechanical properties (microhardness).…”

“…To overcome the drawbacks associated with the high reactivity of BG 45S5, a less reactive, low-Na F-containing BG was formulated and investigated as a functional filler for resin composites. In previous studies with experimental composites functionalized with this low-Na F-containing BG, positive results were obtained for the following properties: acid neutralization [ 17 ], degree of conversion and polymerization kinetics [ 18 ], polymerization shrinkage properties [ 19 ], flexural properties [ 20 ], ion release [ 21 ], and the resulting anti-demineralizing protective effect on enamel [ 22 ] and dentin [ 23 ]. The aim of the present study was to complement these investigations by evaluating properties related to the exposure of composite materials to water, namely microhardness, mass changes during long-term immersion, water sorption and solubility evaluated according to ISO 4049, and surface precipitation of calcium phosphate.…”

Weibull analysis of ceramics and related materials: A review

“…Flexural strength and modulus were appraised using a three-point bending test and WA was done to estimate material reliability. A higher Weibull modulus of 5.0 was obtained, signifying that the material is reliable for the intended applications [ 330 ].…”

Glass-Ceramic Fillers Based on Zinc Oxide–Silica Systems for Dental Composite Resins: Effect on Mechanical Properties

“…Revisiting the research conducted in the field of optimizing the properties of dental polymers, there are many interesting reports. In other words, many fillers have been used to improve the properties of dental polymers, some of which are polyacrylonitrile (PAN) nanofibers [ 2 ], carbon nanotubes modified by silane coupling agents [ 3 ], Ag nanoparticles [ 4 ], quaternary ammonium polyethylenimine nanoparticles (QA-PEI-NPs) [ 5 ], bioactive glass [ 6 ], SiO 2 nanofibers [ 7 ], alumina particles [ 8 ], spherical silica [ 9 ], hydroxyapatite whisker [ 10 ], nano fibrillar silicate [ 11 ], nano-zirconia fillers [ 12 ], electrospun nano-scaled glass fiber [ 13 ], NaF-loaded core–shell PAN–PMMA nanofibers [ 14 ], and APTES- or MPTS-conditioned nanozirconia [ 15 ].…”