Physicochemical Characterization and In Vitro Biocompatibility of Epoxy- and Silicone-Based Endodontic Materials

Root canal sealers play a crucial role in the success of endodontic treatment, facilitating healing and regeneration of the periapical region. This study aimed to evaluate the biological, physicochemical and structural properties of two sealers, AH Plus and ROEKO GuttaFlow 2. Scanning electron microscopy (SEM) analysis reveals polyhedral particles uniformly distributed within the porous organic matrix of AH Plus, whereas ROEKO GuttaFlow 2 exhibits a heterogeneous structure, with particles distributed evenly. Fourier-Transform Infrared Spectroscopy (FT-IR) analysis confirmed the characteristic chemical bonds associated with both the organic and inorganic phases of each material, while X-Ray diffraction analysis identified the main crystalline phases (CaWO₄ and ZrO₂ for AH Plus and ZrSiO₄ and ZrO₂ for ROEKO GuttaFlow 2). The biocompatibility tests were performed on human osteosarcoma cells (ATCC-G 292 CRL-1423). An in vitro metabolic activity and viability test (MTT) showed a significant decrease by ~92% (* p < 0.05) and ~87% after 24 and 48 h for samples incubated with AH Plus versus the control. Regarding ROEKO GuttaFlow 2, MTT levels increased by ~8% in the first 24 h, while after 48 h they decreased by ~11% versus control. Lactate dehydrogenase levels significantly increased at 24 and 48 h for cells incubated with AH Plus (*** p < 0.001, ** p < 0.01). ROEKO GuttaFlow 2 significantly decreased the LDH level at 24 h (** p < 0.01), while at 48 h a rise was observed. The significantly increased levels of nitric oxide observed in cells incubated with the materials at 24 and 48 h (** p < 0.01, *** p < 0.001) suggest a cellular adaptation to our experimental environment. Overall, ROEKO GuttaFlow 2 exhibited a more favorable profile under our testing conditions.