Comparative evaluation of antimicrobial properties of silver nanoparticles and chlorhexidine mouthwashes on the colonization of microflora and oral health during orthodontic treatment: a double-blind randomized controlled trial.

INTRODUCTION: Fixed orthodontic appliances facilitate microbial adhesion and plaque accumulation. Although chlorhexidine has proven to be the most effective antiplaque and antigingivitis agent, it has several side effects. OBJECTIVE: The present study aims to evaluate and compare the effectiveness of silver nanoparticles (SNP) and Chlorhexidine (CHX) mouthwash on reducing the microbial count and improving oral health during fixed orthodontic treatment. TRIAL DESIGN: 4-arm parallel, placebo-controlled, double-blind randomized clinical trial with an allocation ratio of 1:1:1:1. METHODS: Microbial count of Streptococcus spp., Plaque Index, Gingival Index, Gingival Bleeding Index and Pocket Probing Depth were evaluated in 80 orthodontic patients at T0 (Pretreatment), T1 (four weeks after bonding) and T2 (four weeks after mouthwash prescription). Then patients were randomized into four groups: G1) NanOlife (containing SNP), G2) Chlorhex (containing 0.2% chlorhexidine), G3) Placebo, and G4) negative control (no mouthwash prescription) (n=20 each group). The effects of orthodontic treatment and mouthwashes were analyzed statistically. RESULTS: The microbial count and all the four indices increased between T0 and T1 (P<0.05). They decreased below the baseline levels in Gp2, and back to baseline levels in Gp1 at T2 (P<0.05), except Gingival Bleeding index and Pocket Probing Depth. Both mouthwashes showed significantly improved therapeutic effects compared to placebo and negative control. CONCLUSIONS: Although SNP mouthwash was effective in the reduction of all the assessed parameters, it could not decrease them to the baseline levels, suggesting its limited efficacy. CHX mouthwash proved to be extremely effective by decreasing the microbial count, plaque index and gingival index below the baseline level.