In Vivo Investigation of Initial Stages of Enamel Erosion

Inclusion Criteria: * Demonstrates understanding of the study procedures, restrictions and willingness to participate as evidenced by voluntary written informed consent and has received a signed and dated copy of the informed consent form. * Aged at least 18 years * Good general and mental health with, in the opinion of the investigator or medically qualified designee no clinically significant and relevant abnormalities in medical history or upon oral examination. * Absence of any condition that would impact the participant's safety or well-being, or affect the participant's ability to understand and follow study procedures and requirements. * Two anterior maxillary teeth, without signs of toothwear or exposed dentine, facial restorations, abutments for fixed or removable partial dentures, full crowns or veneers, orthodontic bands or cracked enamel that would interfere with the study evaluations. Exclusion Criteria: * Pregnant or breast feeding women * Known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients * Participation in another clinical study (including cosmetic studies) or receipt of an investigational drug within 30 days of the screening visit * Recent history (within the last year) of alcohol or other substance abuse * Presence of a disease or medication which in the opinion of the investigator, will impact on assessments * Gross periodontal disease, treatment of periodontal diseas…