The goal of this clinical trial is to to evaluate the antiplaque and antigingivitis effect of pure green tea mouthwash compared to placebo and essential oils mouthwashes in healthy patients.

The main questions it aims to answer are:

• Does pure green tea mouthwash effectively reduce dental plaque?
• Does pure green tea mouthwash reduce gingival inflammation?

Researchers will compare pure green tea mouthwash to Listerine Total Care, Listerine Green Tea, and placebo to see if there is a difference in plaque accumulation and gum inflammation reduction.

Participants will be prohibited from using any sort of oral hygiene parctice for the whole study period (3 weeks). Instead, they will rinse with 10 ml of their assigned mouthwash twice daily for 30 seconds. Plaque index, gingival index, and staining index will be examined at multiple intervals and participants will rate their sense of oral freshness and good breath.

• Study Design

This study will be a double-blinded, randomized, controlled, clinical trial with a parallel group design. Participants will be randomly allocated into four groups:

Group P: placebo (pure water with a flavored additive) solution. Group T1: pure green tea mouthwash. Group T2: Listerine Total Care mouthwash. Group T3: Listerine Green Tea mouthwash.

All participants will be instructed to rinse with 10 ml of the assigned mouthwash for 30 seconds twice daily over a three-week experimental period. The study will follow the experimental gingivitis model, during which participants will refrain from all forms of mechanical plaque control.

• Sample Size A total of 44 dental participants, aged between 18-50 years, will be recruited. Each group will consist of 11 participants, providing a power of 80% to detect a difference of 0.2 in mean plaque index values between groups, with a p-value < 0.05 and a β-error of 20%.
• Ethical Considerations All participants will be informed about the study objectives, methodology, and possible risks. Written informed consent will be obtained before participation. All procedures will follow ethical standards and the principles of the Declaration of Helsinki.
• Data Collection and Clinical Assessments Clinical examinations will be performed at baseline (T0), day 7 (T1), day 14 (T2), and day 21 (T3). The following parameters will be recorded: plaque index, gingival index, staining index, and patients reported outcome in regards to their perciption of freshness and good breath.

After the experimental period (T3), participants will receive a professional cleaning and fluoride application, and will be followed for two additional weeks to ensure the restoration of oral health.

• Randomization and Blinding Randomization will be performed using a computer-generated sequence by an independent researcher. The mouthwash samples will be provided in coded and unlabeled containers to ensure blinding of both participants and the examiner. A third party will be responsible about desposing the assigned mouth wash to the patients.
• Adverse Events Monitoring Participants will be closely monitored throughout the study for any possible adverse effects such as gingival irritation, sensitivity, or allergic reactions. Any incident will be documented and managed according to the study protocol. Any participant who experience an adverse event will be excluded from the study.

Inclusion criteria:

• Non-smokers
• Systemically healthy
• At least 24 teeth in the functional dentition, excluding third molars
• Clinical diagnosis of periodontal health (no periodontal pockets > 3 mm, bleeding on probing percentage < 10%, and no attachment loss).

Exclusion criteria:

• Smokers.
• Medically compromised patients.
• Pregnant woman.
• Allergies to green tea or EO.
• Any condition that might affect the periodontal tissues.
• Patients with any carious lesions (initial or active).
• Patients who have overhang restorations, poorly designed crowns or bridges, and ortho retainers.
• Use of systemic antibiotics or anti-inflammatory medications within 3 months prior to enrolment.

Individual participant data for plaque index, gingival index, discolouration index, and patient-reported outcomes will be shared. Data will be stripped of all identifiers to protect participant privacy.

Individual Participant Data (IPD) and supporting documents (Study Protocol, Statistical Analysis Plan, Informed Consent Form, and Clinical Study Report) will be made available after publication of the study results, approximately one year after study completion.

Access will be granted to qualified researchers who request the data via email to the principal investigator. Researchers must sign a data use agreement ensuring ethical use, confidentiality, and prohibition of attempts to identify participants.

Participants, investigators, and outcome assessors will be blinded. Mouthwashs will be emptied in opaque bottles. They will be coded and unlabeled. A trained dental assisstant will be responsable about disposing the assigned mouth wash to the patient.