A Study to Assess the Efficacy of an Experimental Mouthwash Used With a Marketed Whitening Toothpaste on Stain Build-up

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 willing and able to comply with scheduled visits, treatment/application/dosing plan, study restrictions, lifestyle considerations 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 ability to understand and follow study procedures and requirements. * At Visit 1 (Screening/Baseline): 1. Participant with good oral health. 2. Participant with at least 16 natural teeth including the 12 anterior teeth. 3. Participant with all facial surfaces, and mandibular lingual surfaces, of the 12 anterior teeth gradable for the MLSI. 4. Participant with presence of extrinsic dental stain (judged to be formed due to ingestion of food or drinks, or use of tobacco products) on the facial surfaces of the anterior teeth, as determined from a gross visual stain assessment. 5. Participant with before Prophylaxis (Baseline)- Total MLSI \[A multiplied by(x) I\] score ((four sites per tooth) of more than equal to (\>=) 15 on the facial surfaces of the six maxillary and six mandibular anterior teeth. Note: Total MLSI score (A x I), scored pre-prophylaxis, will be used for stratification, and is derived from the sum of the A x I scores of the facial surfaces of the six maxillary and six mandibular anterior teeth. Exclusion Criteria: * 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 or psychiatric condition or laboratory abnormality 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 pregnant (self-reported) or intending to become pregnant over the duration of the study. * A participant who is breastfeeding. * A participant with known or suspected intolerance or hypersensitivity to any study materials (or closely related compounds) or any of their stated ingredients. * Participant who is unwilling or, in the opinion of the investigator or medically qualified designee, unable to comply with the requirements and/or lifestyle restrictions of the study. * Participant with a recent history (within the last year) of alcohol or other substance abuse. * Participant with Oral soft tissue (OST) examination findings at Screening which, in the opinion of the investigator, could interfere with the conduct of the study (for example, stomatitis, open sores, lesions, cavitied caries lesions, redness or swelling. * Participant using daily oral care products and/or taking daily doses of medications/treatments which, in the opinion of the investigator or medically qualified designee, could interfere with study outcomes, specifically: 1. Currently daily use of mouthwashes containing ingredients known to cause tooth stain (for example, chlorhexidine or cetylpyridinium chloride). 2. Past or current use of minocycline. 3. Use of tetracycline or doxycycline within 30 days of Screening and/or during the study 4. Daily dose of medications known to cause tooth stain (for example, drugs or supplements containing metal ions known to increase enamel staining). * Participant who has used any professionally dispensed tooth whitening products 6 months prior to baseline or any over-the-counter tooth whitening products (including e.g., peroxide or blue dye containing toothpaste) 3 months prior to baseline. * Specific exclusions for assessment teeth: 1. Non-vital tooth. 2. Tooth with evidence of current or recent carious lesions. 3. Tooth used as an abutment for fixed or partial dentures. 4. Tooth adjacent to fixed retainers and fixed or removable orthodontic appliances. 5. Tooth with surface irregularities, cracked enamel, discoloration due to trauma or orthodontic treatment, tetracycline stain, restorations or hyper/hypoplastic areas, which, in the opinion of the clinical examiner, grading of extrinsic dental stain and tooth shade. 6. Tooth with a crown or veneer. 7. Tooth with exposed dentine which, in the opinion of the investigator, could impact grading of extrinsic dental stain. * General oral exclusions: 1. Generalized severe gingivitis or advanced periodontal disease; treatment of periodontal disease (including surgery) within 12 months of screening; scaling or root planning within 3 months of screening. 2. Any oral condition requiring immediate care. 3. Having received a dental prophylaxis within 8 weeks of screening. * A participant who, in the opinion of the investigator or medically qualified designee, should not participate in the study.