Advanced resin-based composites reinforced with modified montmorillonite

The primary objective of this study was to develop novel resin-based dental composites reinforced with modified sodium montmorillonite (MMT) and to determine the structural and physicochemical properties of these composites. A mixture of barium glass, silica, and MMT was used as the filler system. The organic matrix was based on the monomers Bis-EMA, TEGDMA, and UDMA. MMT was modified using 3-methacryloxypropyltrimethoxysilane (γ-MPS) and cetyltrimethylammonium bromide (CTAB), resulting in two groups of composites. The optimal formulation was determined as 70 wt% filler (7.5 wt% clay) and 30 wt% monomer content. Comprehensive characterization was performed using XRD, SEM, FTIR, and TGA. Mechanical and physical properties were assessed according to ISO 4049 standards, including flexural strength, degree of conversion, depth of cure, water sorption & solubility, polymerization shrinkage, and radiopacity. The results demonstrated that organo-modified MMT enhanced interfacial compatibility between the resin matrix and the filler, enabling uniform dispersion and improved performance. Among the prepared composites, two formulations met the ISO 4049 requirements and showed promising potential for structural intraoral applications. In addition to its favorable interfacial behavior, MMT’s low cost and natural abundance make it a practical alternative to conventional fillers in dental composite systems.