Fabrication of Novel Pre-Polymerized BisGMA/Silica Nanocomposites: Physio-Mechanical Considerations

Abstract

Resin composite mimics tooth tissues both in structure and properties, and thus, they can withstand high biting force and the harsh environmental conditions of the mouth. Various inorganic nano- and micro-fillers are commonly used to enhance these composites’ properties. In this study, we adopted a novel approach by using pre-polymerized bisphenol A-glycidyl methacrylate (BisGMA) ground particles (XL-BisGMA) as fillers in a BisGMA/triethylene glycol dimethacrylate (TEGDMA) resin system in combination with SiO2 nanoparticles. The BisGMA/TEGDMA/SiO2 mixture was filled with various concentrations of XL-BisGMA (0, 2.5, 5, and 10 wt.%). The XL-BisGMA added composites were evaluated for viscosity, degree of conversion (DC), microhardness, and thermal properties. The results demonstrated that the addition of a lower concentration of XL-BisGMA particles (2.5 wt.%) significantly reduced (p ≤ 0.05) the complex viscosity from 374.6 (Pa·s) to 170.84. (Pa·s). Similarly, DC was also increased significantly (p ≤ 0.05) by the addition of 2.5 wt.% XL-BisGMA, with the pristine composite showing a DC of (62.19 ± 3.2%) increased to (69.10 ± 3.4%). Moreover, the decomposition temperature has been increased from 410 °C for the pristine composite (BT-SB0) to 450 °C for the composite with 10 wt.% of XL-BisGMA (BT-SB10). The microhardness has also been significantly reduced (p ≤ 0.05) from 47.44 HV for the pristine composite (BT-SB0) to 29.91 HV for the composite with 2.5 wt.% of XL-BisGMA (BT-SB2.5). These results suggest that a XL-BisGMA could be used to a certain percentage as a promising filler in combination with inorganic fillers to enhance the DC and flow properties of the corresponding resin-based dental composites.

Advancing Dimethacrylate Dental Composites by Synergy of Pre-Polymerized TEGDMA Co-Filler: A Physio-Mechanical Evaluation

“…The TEGDMA powder particles were synthesized via a bulk polymerization reaction. The reaction was performed by thermal initiation using AIBN under inert N 2 [24]. The synthesis process is depicted in Figure 1.…”

“…The filler portion was of S-SiO 2 type, which was sequentially replaced with 0.0, 2.5, 5, and 10% of the synthesized pre-polymerized TEGDMA powder. The components were mixed following a recommended method [24] and the resulting composites were termed TRCx, where x is the P-TEGDMA (g) per 50 g filler, as summarized in Table 1. Briefly, the initiation system was introduced into the BisGMA and TEGDMA mixture, and then the corresponding fillers were suspended.…”

“…By varying the filler particle size and shape, the various features of the resulting DRCs could be altered, including surface roughness and polishing retention, mechanical strength, and toughness [21,22]. Owing to their high surface-tovolume ratio, small particles improve and increase the viscosity of resin by increasing filler-to-matrix interaction and reducing the filler loading [23,24]. Based on the size of reinforcing fillers, the RDC is characterized as nanofilled (5-100 nm), micro-filled (40-50 nm), hybrid (10-50 µm + 40 nm), nanohybrid (0.6-1 µm + 5-100 nm), microhybrid (0.6-1 µm + 40 nm), and midifilled (1-10 µm + 40 nm) [25].…”