Development of novel dental composites integrated with MSN–TQ systems

Thymoquinone (TQ), recognized for its potent antibacterial capabilities, is a promising compound for both preventive and therapeutic applications in various diseases. In this study, TQ molecules were successfully loaded onto biocompatible, easily synthesized, and cost-effective MSN, creating the MSN–TQ system, which was subsequently incorporated into the synthesis of a novel series of dental composites. The chemical characterization of both the MSN–TQ system and the resulting S series dental composites was carried out using FTIR, SEM, XRD, TGA, and DSC. The antibacterial activity of MSN–TQ nanoparticles were assessed by MIC and MBC assays against E. coli , S. aureus , E. faecalis , and P. aeruginosa . MSN–TQ showed selective efficacy against E. faecalis (MIC/MBC: 7.5–10 μg/mL); no activity against E. coli , S. aureus , or P. aeruginosa within 2.5–20 μg/mL. Compared to resin without MSN-TQ, the surface bacterial metabolic activity was found to be lowest in S4 composite (49.28%) among S series dental composites. The S4 dental composite exhibited the maximum water solubility value (5,72*10 -3 mg/mm 3 ), whereas the S0 control composite (lowest filler content) demonstrated the highest water sorption value (73,04*10 -2 mg/mm 3 ). Furthermore, following exposure to the Fenton chemical challenge, the maximum material loss due to degradation was recorded in the S3 composite, reaching 0.020%. These findings position MSN-TQ composites as a scientifically promising direction requiring further work: cytotoxicity (ISO 10993-5), aging, wear, fatigue, and bond strength studies are needed before any clinical consideration. • MSN–TQ synthesized and incorporated into dental composites • Selective antibacterial effect vs E. faecalis (7.5–10 μg/mL) • S4 composite showed lowest surface bacterial metabolic activity • S3 achieved highest compressive strength (184.64 MPa)