Evaluation of the cell viability and antimicrobial effects of orthodontic bands coated with silver or zinc oxide nanoparticles: An in vitro study

OBJECTIVE: We aimed to evaluate the cell viability and antimicrobial effects of orthodontic bands coated with silver or zinc oxide nanoparticles (nano-Ag and nano-ZnO, respectively). METHODS: In this experimental study, 30 orthodontic bands were divided into three groups (n = 10 each) control (uncoated band), Ag (silver-coated band), and ZnO (zinc oxide-coated band). The electrostatic spray-assisted vapor deposition method was used to coat orthodontic bands with nano-Ag or nano-ZnO. The biofilm inhibition test was used to assess the antimicrobial effectiveness of nano-Ag and nano-ZnO against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Biocompatibility tests were conducted using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The groups were compared using one-way analysis of variance with a post-hoc test. RESULTS: The Ag group showed a significantly higher reduction in the number of L. acidophilus, C. albicans, and S. mutans colonies than the ZnO group (p = 0.015, 0.003, and 0.005, respectively). Compared with the control group, the Ag group showed a 2-log(10) reduction in all the microorganisms' replication ability, but only S. mutants showed a 2-log(10) reduction in replication ability in the ZnO group. The lowest mean cell viability was observed in the Ag group, but the difference between the groups was insignificant (p > 0.05). CONCLUSIONS: Coating orthodontic bands with nano-ZnO or nano-Ag induced antimicrobial effects against oral pathogens. Among the nanoparticles, nano-Ag showed the best antimicrobial activity and nano-ZnO showed the highest biocompatibility.