The goal of this clinical trial is to evaluate and compare the antiplaque efficacy and patient reported outcome of three commonly used antiseptic mouthwashes - Chlorhexidine (CHX), Cetylpyridinium Chloride (CPC), and Essential Oil (EO) formulations - in orthodontic patients undergoing fixed appliance therapy. The main question it aims to answer is:

In orthodontic patients wearing fixed appliances, what is the comparative effect of chlorhexidine, cetylpyridinium chloride, and essential-oil mouthwashes versus placebo on clinical periodontal parameters, salivary IL-1β levels, and patient-reported outcomes.

Prior to enrollment in the clinical trial, all potential participants will undergo a preparatory phase for one month aimed at achieving optimal oral health and minimizing confounding baseline inflammation. During this phase, participants will receive a full professional oral prophylaxis, including scaling and polishing, to remove dental plaque and calculus deposits. This ensures that all individuals begin the study with a comparable level of oral hygiene and gingival health.

Participants will be instructed on a standardized oral hygiene regimen, including proper toothbrushing technique using a soft-bristled toothbrush and fluoridated toothpaste twice daily. In addition, each participant will be provided with a single-tufted brush as an interproximal cleaning aid to maintain plaque control around orthodontic brackets and hard-to-reach areas. The use of any other mouthwash or adjunctive antimicrobial agent will be prohibited during this phase. After preparatory phase, participants will undergo a four-day plaque-accumulation period immediately prior to baseline clinical and biochemical assessments. During this 4-day period participants will be instructed to refrain from all mechanical oral hygiene procedures (no toothbrushing, interdental cleaning, or mouthrinse use) in order to standardize plaque formation across subjects and create a measurable baseline plaque burden for subsequent comparisons.

After that, In base line visit the salivary sample will be collected for IL-1β measurement and clinical periodontal parameters (PI,GI,BOP,PPD) will be measured and receiving oral hygiene instructions and motivation, and first intervention will be given to the patient.

After one week Saliva will be collected for IL-1β measurement and the clinical measurements ( PI,GI,BOP)will be taken, then the participant goes into washout period for two weeks, after that the participant will be called to repeat the same protocol for the remaining three interventions.

Inclusion Criteria:

• Age 14-30 years.
• Wearing orthometric-type fixed orthodontic appliances(metallic brackets and archwires) and currently in alignment stage.
• Able and willing to attend all study visits and comply with study procedures, including washout periods and mouthwash use.
• Baseline oral status after preparatory phase: plaque index (Löe & Silness) ≥ 1.0 and gingival index (Löe & Silness) ≥ 0.5.
• BOP less than 10%.
• Systemically healthy individuals with no history of antibiotic use or other medications in the preceding 3 months.
• Willing to refrain from using any other mouthwash or antimicrobial oral hygiene product (except for the assigned study mouthwash and their routine toothpaste) throughout the study.
• Provide written informed consent (and parental/guardian consent if under legal age).

Exclusion Criteria:

• Periodontitis patients and untreated caries requiring urgent care.
• Smoking or use of tobacoo/nicotine products(including vaping).
• Known allergy or hypersensitivity to CHX, CPC, EO components (thymol, eucalyptol, menthol, methyl salicylate), or any ingredient in the study formulations.
• Pregnancy or breastfeeding.
• Use of any antiseptic mouthwash, oral probiotic, or antimicrobial gel in the 3 months prior to baseline.

This is a triple-blind design in which the participants, the examiner, and the analyst/statistician all will be blinded to the identity of the mouthwash.

The supervisor is the only person aware of the mouthwash identity, she will use empty bottles of the same size and shape for the interventions, label them with English letters(A, B, C, D), and distribute them according to a randomized sequence generated using a computer program. The examiner will follow the treatment sequence given for every patient.