Antibacterial and Antibiofilm Effects of Zinc Oxide and Magnesium Oxide Nanoparticles Against Periodontal Pathogens: An In Vitro Study
Keywords:
Zinc oxide nanoparticles, magnesium oxide nanoparticles, nanotechnology in dentistry, oral streptococciAbstract
Background: Periodontal disease is a common, multifactorial inflammatory condition affecting the supporting structures of teeth, leading to gingival inflammation, alveolar bone loss, and eventual tooth loss. Microbial biofilm accumulation is the primary cause, triggering chronic tissue damage. Conventional treatments, including mechanical debridement and chemical agents, can cause side effects such as tooth staining and mucosal irritation. Nanoparticles like zinc oxide (ZnO) and magnesium oxide (MgO), combined with antioxidants such as vitamin E, have shown promising antimicrobial and antibiofilm activity in vitro.
Aim: This study evaluated the antimicrobial and antibiofilm effects of ZnO NPs and MgO NPs, against early oral biofilm formers, incorporated into an alcohol-free mouthwash (Listerine®).
Materials and Methods: Supragingival plaque samples from 20 healthy individuals were collected aseptically. Streptococcus mitis and Streptococcus oralis were isolated and confirmed by PCR. ZnO NPs and MgO NPs were tested individually and in combination . Listerine® served as a positive control. Five biological replicates per treatment were used, based on G*Power analysis. Antibacterial activity was assessed via agar well diffusion, MIC, MBC, and sub-MIC determinations, while antibiofilm activity was measured by optical density (OD₆₀₀).
Results: ZnO and Mix nanoparticles strongly inhibited biofilm formation (OD₆₀₀ = 0.149–0.177), MgO showed moderate inhibition. Percent biofilm inhibition was highest for Mix and ZnO (>88%) and moderate for MgO. Mix nanoparticles exhibited the strongest antibacterial activity (MIC: 12.0 ± 4.4 µg/ml for S. mitis, 5.3 ± 2.1 µg/ml for S. oralis), producing the largest inhibition zones (28.3 ± 0.8 mm and 27.0 ± 1.9 mm).
Conclusion: Incorporating ZnO and MgO nanoparticles into mouthwash enhances antibiofilm and antibacterial efficacy against early oral biofilm formers, offering a promising adjunctive approach for periodontal disease management.
