Once IC has been obtained, resting and stimulated salivary flow rate will be measured by the Investigators or delegated member of the research team using a Saliva-Check Buffer kit (GC Corp, Leuven, Belgium). The kit will allow observation of the quantity and viscosity of resting saliva produced in one minute, and the pH of the sample will also be tested and recorded. Participants will then chew a piece of paraffin wax for a two-minute period to produce a stimulated salivary sample. The liquid component of the sample will be measured to allow a flow rate in ml/minute to be calculated, and the pH again tested and recorded. The buffering capacity of the stimulated saliva will also be determined by challenging the saliva with varying amounts of lactic acid. As a lack of saliva would bias the results for the study due to increased caries risk, and as saliva is essential for the hydrolysis of the CPP-ACP from the TM, if the resting salivary flow rate is below 0.2ml/min, or the stimulated rate below 1.0ml/min, then the subject will be excluded from the study. Participants will then be randomly allocated to the control or the experimental group.