In Situ Erosion Study to Investigate the Effectiveness of an Experimental Toothpaste

This will be a randomized, controlled, single center, single- blind, 3 period, 3 treatment, cross-over, in situ design which consists of placing pre-eroded bovine enamel specimens intra orally using a palatal appliance and testing the remineralizing performance of the experimental (dentifrice containing 0.254 Percent weight by weight \[%, w/w\] sodium fluoride (1150 parts per million \[ppm\] fluoride) and 5% KNO3 \[potassium nitrate\]), comparator (dentifrice containing 0.454% w/w stannous fluoride (1100 ppm fluoride) and placebo (Fluoride free placebo containing 5% KNO3 \[0 ppm fluoride\] ) dentifrices 2 and 4 hours (hrs) post treatment application, based on surface micro hardness measurements. This study will be carried out in healthy adults with a maxillary dental arch suitable for the retention of the palatal appliance.

The aim of this study is to investigate the performance of an experimental dentifrice formulation in promoting enamel remineralization and inhibiting post-treatment enamel demineralization in an in situ erosion model, in comparison with a fluoride-free placebo and with a marketed competitor dentifrice product. The study will have 4 visits, 1 screening visit to assess participants eligibility and 3 treatment visits to assess product efficacy, where the treatment product will be dispensed and used under the supervision of a suitably trained study site personnel. Prior to each treatment visit, there will be a washout period of a minimum of 3 days. During this period participants will use their own dentifrice for at least one day, and a fluoride free dentifrice (provided) for two days prior to the next scheduled visit (including in the morning of the scheduled visit) to minimize any carry-over effects of the fluoride toothpaste.

Eligibility Criteria:
Inclusion Criteria:

* Evidence of a personally signed and dated informed consent.
* Male and female participants who, at the time of screening, are between the ages of 18 and 65 years, inclusive.
* Participant who is willing and able to comply with scheduled visits, treatment plan, and other study procedures.
* 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 oral examination.
* Male participant able to father children and female participant of childbearing potential and at risk for pregnancy must agree to use a highly effective method of contraception throughout the study and for 5 days after the last dose of assigned treatment.
* Good oral health without lesions of the oral cavity that could interfere with the study evaluations.
* Maxillary dental arch suitable for the retention of the palatal appliance
* Unstimulated salivary flow rate of at least 0.2 mL/minute and a stimulated salivary flow rate of at least 0.8 mL/minute.
* Understands and is willing, able and likely to comply with all study procedures and restrictions.

Exclusion Criteria:

* Participants who are investigational site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, or participants who are GSK employees directly involved in the conduct of the study.
* Participation in other studies involving investigational drug(s) within 30 days prior to screening visit.
* Participation in other studies involving investigational oral care or cosmetic products within 30 days prior to screening visit.
* Acute or chronic medical or psychiatric condition 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, would make the participant inappropriate for entry into this study.
* Pregnant female participant (self - reported).
* Breastfeeding female participant.
* Known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients. Unwilling or unable to comply with the lifestyle guidelines described in this protocol.
* Medication that may interfere significantly with the saliva flow in the judgment of the investigator. Should new medications that may interfere with the saliva flow be added, a second salivary flow test will be performed.
* Participant with any condition that would impact on their safety or wellbeing or affect their ability to understand and follow study procedures and requirements.
* Any sign of grossly carious lesions (active), moderate or severe periodontal conditions, or severe tooth wear. Participant presenting at screening with minor caries may continue in the study if their carious lesions are repaired prior to the first treatment visit of the study.
* Wears oral appliance or orthodontia (besides participants wearing permanent lower retainers, which are eligible).
* Recent history (within the last year) of alcohol or other substance abuse. Participant who has previously been enrolled in this study.