A Clinical Study to Evaluate the Efficacy of a Cetylpyridinium Chloride Mouthwash in Improving Gingival Health and Reducing Plaque Accumulation

Inclusion Criteria: * Participant provision of a signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study before any assessment is performed. * Participant is of either sex and any gender who, at the time of screening, is at least 18 years old, inclusive. * A participant who is willing and able to comply with scheduled visits, treatment plan and other study procedures. * A participant in good general and mental health with, in the opinion of the investigator or medically qualified designee, no clinically significant or relevant abnormalities in medical history or upon oral examination, or condition, that would impact the participant's safety, wellbeing or the outcome of the study, if they were to participate in the study, or affect the individual's ability to understand and follow study procedures and requirements. * Participant oral health that meets all the following: * At screening (visit 1): 1. Participant with at least 20 natural, permanent teeth. 2. Participant with at least 40 evaluable surfaces for MGI, bleeding index (BI), and TPI. 3. A participant with plaque-induced gingivitis, in the opinion of the clinical examiner, as confirmed by a gross visual examination at the screening visit. * At baseline (visit 2; prior to dental prophylaxis) 1. A participant with 10% to 30% bleeding sites. 2. A participant with overall TPI score \>=1.5. Exclusion Criteria: * A participant who is an employee of the investigational site, either directly involved in the conduct of the study or a member of their immediate family; or an employee of the investigational site otherwise supervised by the investigator; or a Haleon employee directly involved in the conduct of the study or a member of their immediate family. * A participant who has participated in other studies (including non-medicinal studies) involving investigational product(s) within 30 days prior to study entry and/or during study participation. * A participant with, in the opinion of the investigator or medically qualified designee, an acute or chronic medical, psychiatric condition or laboratory abnormality or any other clinical serious or unstable conditions (for example, cardiovascular diseases, diabetes, liver disorders, and kidney disorders) that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator or medically qualified designee, would make the participant inappropriate for entry into this study. * A participant who is a pregnant female (self-reported) or intending to become pregnant over the duration of the study. * A female participant who is breastfeeding. * A participant with known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients. * A participant unwilling or unable to comply with the Lifestyle Considerations described in this protocol. * A participant who is a current smoker or an ex-smoker (including vaping) who stopped within 6 months of Screening. * A participant who is using smokeless forms of tobacco (for example, chewing tobacco, gutkha, pan containing tobacco, nicotine-based e-cigarettes). * A participant who is diagnosed with xerostomia or is taking any medication that in the view of the investigator is causing xerostomia. * A participant who has a medical condition which could have directly influenced gingival bleeding (for example, type 2 diabetes). * A participant who has a bleeding disorder that could have affected study outcomes and/or participant safety. * A participant who has a recent history (within the last year) of alcohol or other substance abuse. * A participant who has a severe oral condition (for example, acute necrotizing ulcerative gingivitis or oral or peri-oral ulceration including herpetic lesions) that could, in the opinion of the investigator, compromise study outcomes or the oral health of the participant/examiner if they participate in the study. * Presence of a tongue or lip piercing, or any other oral feature that could interfere with the usage of a toothbrush. * Medication exclusions: At screening (Visit 1): 1. A participant using any antibiotic medication within 4 weeks prior to screening or at any time during the study. 2. A participant currently taking an anti-inflammatory medication which, in the opinion of the Investigator, could affect gingival condition. 3. A participant currently taking a systemic medication (for example, anti-inflammatory, anticoagulant, immunosuppressants) or traditional/ herbal remedy or as a premedication requirement before an invasive examinations and prophylaxis (for example, knee replacement, Mitral valve prolapse etc.), which, in the opinion of the Investigator, could affect plaque/ gingival condition (for example, ibuprofen, aspirin, warfarin, cyclosporin, phenytoin, calcium channel blockers). 4. A participant who has used an antibacterial dentifrice or mouthwash (for example, chlorhexidine) or any oral care product that in the view of the investigator could interfere with plaque formation or measures of gingivitis, within 4 weeks prior to screening. * Medication exclusions: At baseline (Visit 2): 1. A participant who has taken (in the previous 4 weeks), any antibiotics. 2. A participant who requires the need for antibiotic premedication prior to a dental prophylaxis or taking some blood thinning medication that prohibit the safe conduct of a dental cleaning. Note: Medical consultation may need to be obtained from participant's physician at the examiner's discretion. 3. A participant who has taken (in the previous 4 weeks) a systemic medication (for example, anti-inflammatory, anti-coagulant, immunosuppressants) or traditional/ herbal remedy as a premedication requirement before an invasive examinations and prophylaxis (for example, knee replacement, Mitral valve prolapse etc.), which, in the opinion of the Investigator, could affect plaque/ gingival condition (for example, ibuprofen, aspirin, warfarin, cyclosporin, phenytoin, calcium channel blockers). 4. A participant who has used an antibacterial dentifrice or mouthwash (for example, chlorhexidine) or any oral care product that in the view of the investigator could interfere with plaque formation or measures of gingivitis, in the period between Screening and the Baseline visit. * Periodontal exclusions: 1. A participant who has more than three tooth sites with probing pocket depth \>=4 mm. 2. A participant who is receiving or has received treatment for periodontal disease (including surgery) within 12 months of Screening. 3. A participant who has gingivitis, which in the opinion of the investigator, is not expected to respond to treatment with an over the counter (OTC) dentifrice. * Dental exclusions: 1. A participant who has active caries that could, in the opinion of the investigator, compromise study outcomes or the oral health of the participant if they participate in the study. 2. A participant who has dentures (partial or full). 3. A participant who has an orthodontic appliance (bands, appliances, or fixed/ removable retainers). 4. A participant who received orthodontic therapy within 3 months of Screening. 5. A participant who has numerous restorations in a poor state of repair. 6. A participant who has any dental condition (for example, overcrowding) that could, in the opinion of the investigator, compromise study outcomes or the oral health of the participant if they participate in the study. 7. A participant who has had dental prophylaxis within 12 weeks of Screening. 8. A participant who has had teeth bleaching within 12 weeks of Screening. 9. A participant who has high levels of extrinsic stain or calculus deposits, in the opinion of the investigator, that could have interfered with plaque assessments. * A participant who has previously been enrolled in this study. * A participant who, in the opinion of the investigator or medically qualified designee, should not participate in the study.