- Participants who have the following specific dental exclusions for assessment teeth: a) Any tooth which, in the opinion of the investigator, appears to be non-vital based on changes in the intrinsic colour. b) Tooth with evidence of current or recent caries, or reported treatment of decay in 12 months of screening. c) Tooth with exposed dentine which, in the opinion of the investigator, could impact grading of extrinsic dental stain; tooth with deep, defective or facial restorations; tooth used as an abutment for fixed or removable partial dentures; tooth with full crown or veneer, orthodontic bands or cracked enamel. d) Tooth with surface irregularities, discoloration due to trauma, tetracycline stain, restorations, or hypo or hyperplasic areas which, in the opinion of the investigator, would prevent consistent grading of extrinsic dental stain. e) High levels of calculus deposits which might interfere with plaque assessments at the discretion of the investigator. f) Presence of orthodontic bands or appliances, extensive crowns, partial dentures, or fixed retainers.