In-situ sol-gel process for the formulation of Bis-GMA/TEGDMA/silica dental nanocomposite

A novel dental composite based on Bis-GMA/TEGDMA resin incorporating silica nanoparticles was developed using an innovative in situ sol-gel process. This method ensures a homogeneous dispersion of fillers, effectively preventing their agglomeration during preparation. It results in an interpenetrating network in which polymer chains and silica particles are intimately mixed, thereby enhancing the structural and mechanical properties and minimizing the volumetric shrinkage of the dental restorative material. The formation of organic and inorganic network was confirmed by infrared spectroscopy. The in situ synthesis enabled uniform dispersion of silica nanoparticles within the material as evidenced by transmission electron microscopy, scanning electron microscopy and energy dispersive spectroscopy. The results showed that the prepared composite containing 50 wt% fillers achieved hardness, modulus of elasticity, compressive strength and flexural strength values of 72 HV, 10 GPa, 240 MPa, and 110 MPa, respectively. These properties are comparable to those of the commercial “Nt Premium” composite containing 75 % preformed silica nanoparticles, which has hardness, modulus of elasticity, compressive strength and flexural strength values of 68 HV, 10 GPa, 220 MPa and 95 MPa, respectively. Additionally, the study revealed a significantly reduced volumetric shrinkage of 0.5 % for our composite, compared with over 2.2 % for Nt Premium. This groundbreaking approach holds substantial promise for developing advanced dental materials, offering superior performance and enhanced longevity in clinical applications. • The in-situ generation of silica nanoparticles improves dispersion in the matrix, as revealed by microscopic analysis. • The composites' mechanical properties are comparable to those of commercial ones. • Low volumetric shrinkage values are obtained for composites formulated in situ.