Epoxy resin-based sealers modified with clay nanoparticles: Evaluation of their physicochemical and mechanical...

Epoxy resin-based sealers are commonly used in endodontic treatment due to their superior physicochemical properties. Therefore, it is important to utilize these materials by enhancing their properties. Nonetheless, several of their properties remain suboptimal, including the relatively prolonged setting time, the moderate yet clinically relevant solubility, the limitations in flow, and the need for enhanced dimensional stability. This study aimed to investigate the effect of different concentrations of organically modified montmorillonite (MMT) nanoclays on the physicochemical properties of two epoxy resin endodontic sealers. Sealers AH26 and AHplus were tested in their commercial unmodified form (controls) and with the addition of 0.5%, 1%, and 2% MMT modified with cetyltrimethylammonium. The morphological and structural characteristics of the obtained nanocomposites were studied by means of scanning electron microscopy and x-ray diffraction. The study included five evaluations: setting time, flowability, solubility, dimensional change, and compressive strength of the sealers, following the International Standard Organization 6876:2001. The setting time, flow, and solubility values of all modified samples were lower, whereas the compressive strength was higher than seen for unmodified sealers. However, the dimensional change in the control group for both sealers was significantly lower than in the nanoparticle groups.