Assessment of the Antimicrobial Properties of Mesoporous Zinc Oxide Nanoparticles Against Streptococcus mutans: An In Vitro Investigation.

Background: This study focused on synthesizing and characterizing mesoporous zinc oxide nanoparticles (ZnO NPs) while evaluating their antibacterial effectiveness against Streptococcus mutans. Their antimicrobial properties were compared to conventional ZnO NPs using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. Methods: Mesoporous ZnO NPs were produced and analyzed for structural properties. Their antibacterial potential was assessed through MIC and MBC determinations, along with inhibition zone measurements. The test groups included calcined and noncalcined mesoporous ZnO NP solutions (10 mg/mL), standard ZnO NP solution (10 mg/mL), normal saline, and chlorhexidine (CHX) solution (2 mg/mL). Results: All ZnO NP solutions exhibited an MIC of 5 mg/mL, with lower concentrations (2.5 mg/mL and below) showing no inhibition against S. mutans. The MIC for CHX (2 mg/mL) was found to be 0.156 mg/mL. MBC values matched MIC results for all NP solutions (5 mg/mL), whereas CHX had an MBC of 0.312 mg/mL. Among the tested solutions, the calcined mesoporous ZnO NP solution produced the largest inhibition zone (19 ± 0.02 mm), followed by the noncalcined version (17.2 ± 0.03 mm). CHX (14.9 ± 0.02 mm) and ZnO NP solution (15.2 ± 0.13 mm) showed similar inhibitory effects. Conclusion: The study suggests that mesoporous ZnO NP solution possesses strong antibacterial properties against S. mutans, offering a promising alternative to CHX, which is widely used in dental disinfection. These findings highlight the potential application of mesoporous ZnO NPs in various dental procedures, including endodontics, restorative treatments, and periodontal therapy.