Dental plaque is a biofilm that accumulates on tooth surfaces and is a primary factor in the development of gingival inflammation. While toothbrushing remains the main method for plaque control, the effectiveness of mechanical oral hygiene depends largely on individual compliance and technique. As a result, mouthwashes are commonly used as adjunctive chemical plaque control agents.

Chlorhexidine gluconate is an effective anti-plaque mouthwash, but its use is associated with undesirable effects that may limit patient acceptance. Resveratrol is a naturally derived compound with reported antimicrobial and anti-biofilm properties, suggesting its potential use as an alternative chemical plaque control agent.

This randomized, double-blind, placebo-controlled, three-period crossover clinical trial aims to evaluate the short-term anti-plaque effect of a resveratrol-based mouthwash by measuring supragingival plaque regrowth over a 24-hour period in periodontally healthy individuals. The effects of the resveratrol-based mouthwash will be compared with 0.12% chlorhexidine (CHX) and a placebo mouthwash under standardized conditions without mechanical oral hygiene

This study is a randomized, double-blind, placebo-controlled, three-period crossover clinical trial conducted in periodontally healthy individuals to evaluate the short-term anti-plaque efficacy of a resveratrol-based mouthwash. The study population will consist of systemically healthy undergraduate dental students with clinically healthy gingiva and no signs of gingivitis or periodontitis. This population was selected to allow accurate assessment of supragingival plaque re-growth without the influence of periodontal inflammation or periodontal pocketing.

Prior to the clinical trial, participants will undergo a one-week preparatory period during which oral hygiene instructions will be provided and professional scaling and polishing will be performed to obtain plaque-free tooth surfaces. Standardized oral hygiene aids will be supplied for use during the preparatory and washout periods.

Participants will be randomly assigned to different intervention sequences determining the order of the three mouthwashes using a computer-generated randomization list prepared by an independent individual not involved in the clinical examinations. To minimize bias, the study will be conducted in a double-blind manner, with the test, positive control, and placebo mouthwashes dispensed in identical opaque bottles. Both participants and the examiner will remain blinded to the identity of the interventions until completion of all study phases.

At the beginning of each intervention period, supragingival plaque will be disclosed and removed by professional polishing to standardize baseline conditions. Participants will then rinse with 10 milliliters of the assigned mouthwash for 30 seconds under supervision and will be instructed to refrain from eating or drinking for 30 minutes. A second rinse will be performed after 12 hours. Participants will be instructed to refrain from all mechanical oral hygiene measures and the use of additional oral hygiene products during the 24-hour experimental period.

After 24 hours, supragingival plaque accumulation will be assessed using the Modified Quigley-Hein Plaque Index (MQHPI). Digital plaque image analysis (DPIA) will be performed using fluorescein-disclosed ultraviolet images to quantify plaque-covered tooth surfaces. Following plaque assessment, professional polishing will be carried out.

Each intervention phase will be separated by a six-day washout period to minimize potential carryover effects. During the washout period, participants will resume routine oral hygiene practices using standardized oral hygiene aids. The short-term safety and acceptability of the tested mouthwashes will be assessed throughout the study

Inclusion Criteria:

• Age between 18 and 30 years
• Systemically healthy individuals
• Presence of at least 20 natural teeth
• Clinically healthy gingiva with no signs of gingivitis or periodontitis
• No probing depth >3 mm
• No clinical attachment loss

Exclusion Criteria:

• Presence of gingivitis or periodontitis
• Active dental caries requiring treatment
• History of periodontal therapy within the previous 6 months
• Use of antibiotics, anti-inflammatory drugs, or antiseptic mouthwashes within the previous 3 months
• Smoking or tobacco use
• Pregnancy or lactation
• Known allergy to any mouthwash components

The products will be packaged in such a way that they are not recognizable neither by the operator, nor by the patient. Each package will be assigned a number that in turn will refer to the type of the product. The association between the number and type of the product will be collected by another operator according to the association carried out by a dedicated software. The operator who will deliver the product will be informed about the type only at the end of the treatment.