Salivary Microbiota and Antimicrobial Resistance in Relation to Chlorhexidine Use

Inclusion Criteria: * Age: Between 25-44 years. * General Health: Good systemic health (absence of chronic inflammatory diseases or conditions affecting oral tissues). * Oral Hygiene Routine: Participants must perform toothbrushing twice a day and use interdental cleaning aids once a day. * Plaque Index (PI): A score of 0.0-0.2 according to Silness and Löe. * Gingival Index (GI): A score of 0.0-0.143 according to Silness and Löe. Exclusion Criteria: Systemic and Lifestyle Factors: * Presence of any chronic systemic disease (e.g., diabetes mellitus, autoimmune disorders) * Regular use of medications that may affect gingival status or saliva production. * Use of antibiotics within the last 6 months prior to the study. * Current pregnancy or lactation. * Current smokers or users of other tobacco/nicotine products. Oral and Dental Factors: * Active dental disease: Presence of untreated tooth decay, gingivitis (GI \> 0.143), or any form of periodontitis. * Prosthetics and Implants: Presence of dental implants, dentures, or significant tooth loss (excluding extracted third molars). * Ongoing fixed or removable orthodontic treatment.