Comparative evaluation of antimicrobial efficacy of silver oxide nano particles and chlorhexidine mouthwash when used alone and in combination on orthodontic brackets: an In-vitro study

Chlorhexidine (CHX) gluconate is a widely recognized antimicrobial agent in dentistry known for its ability to eradicate oral microbial populations. Silver nanoparticles (AgNP) are effective antimicrobial agents frequently utilized in various medical applications. After fixed orthodontic treatment, enamel demineralization may occur in approximately 50% of patients. Aim : The aim of this study was to compare the antimicrobial efficacy of 0.2% chlorhexidine mouthwash and silver oxidecoated nanoparticles when used alone and in combination on orthodontic brackets against Streptococcus mutans(S.mutans). S.mutans has been identified as factors that support the development of cariogenic microbiota. The synergistic effect of the two solutions has been evaluated in this study. Materials and Methods: 30 premolar stainless steel brackets were divided into three groups (A, B, C). Each group consisted of 10 brackets. Brackets in group A was immersed in 0.2% chlorhexidine. Brackets in group B was coated with silver oxide nanoparticles. Brackets in group C was immersed in 0.2% chlorhexidine solution after coating with silver oxide nanoparticles (CHX-AgONP). Brackets then were subjected to microbiological tests for assessment antibacterial properties against S.mutans. Results: The multiple comparison of mean differences in Colony Forming Units (CFUs) of S. Mutans at a 14-day period reveals the following findings among the three groups. Group C showed significantly least mean CFU counts compared to Group A, with mean difference of 1.595 (95% CI, 0.106 to 3.084) and Group B, with mean difference of 12.337 (95% CI, 10.748 to 13.726) and the mean differences were statistically significant at p=0.03 & p<0.001 respectively. This was then followed by Group A which showed significantly lesser mean CFU counts as compared to Group B, with mean difference of -10.642 (95% CI, -12.131 to -9.153) and the mean difference was statistically significant at p<0.001. This implies that, Group C showed significant reduction in mean CFUs count, followed by Group A and least in Group B at 14 days Incubation period. CHXAgONP combined solution exhibited the highest efficacy in comparison to these solutions used alone. Conclusion: The present study demonstrates the antimicrobial efficacy of a novel mixture of CHX-AgONP solution, and it may be developed as a promising antimicrobial agent against S.mutans