Silver Nanoparticle vs Chlorhexidine Mouthwashes for Reducing Streptococcus Mutans and Improving Salivary pH in Children

Dental caries remains one of the most common chronic diseases in children, with Streptococcus mutans playing a major role in its development. Chlorhexidine mouthwash is an effective antimicrobial agent but its use in pediatric patients is limited by adverse effects such as tooth staining, taste alteration, and mucosal irritation. Silver nanoparticle (AgNP) mouthwash has emerged as a potential alternative with broad-spectrum antimicrobial activity and a potentially improved safety profile. This randomized, double-blind, parallel-group clinical trial will compare the efficacy of 10 ppm silver nanoparticle mouthwash with 0.2% chlorhexidine mouthwash in reducing salivary Streptococcus mutans levels in children aged 6-12 years at high caries risk.

Inclusion Criteria: * (1) age 6-12 years with mixed dentition; (2) American Society of Anesthesiologists (ASA) physical status I or II; (3) high caries risk, defined as DMFT/dmft score ≥ 3, Dentocult SM Strip mutans score ≥ 2, or salivary S. mutans ≥ 10⁵ CFU/mL at screening; (4) presence of at least 20 natural teeth; (5) no antibiotic therapy in the preceding 3 months; (6) parent/guardian willing to provide written informed consent; and (7) child assent obtained using age-appropriate methods. Exclusion Criteria: * 1\) systemic diseases affecting salivary flow (e.g., Sjögren's syndrome, uncontrolled diabetes, cystic fibrosis); (2) special healthcare needs or developmental disabilities affecting compliance; (3) active fixed or removable orthodontic appliances; (4) history of allergy to silver compounds, chlorhexidine, or mint flavoring; (5) use of any antimicrobial mouthwash in the preceding 3 months; (6) active oral mucosal lesions or periodontal disease; (7) professional fluoride treatment within the past month; and (8) participation in another clinical trial within the past 6 months.