For the clinical study, patients identified by the Investigator from those attending routine dental appointments, who meet all the inclusion and exclusion criteria will be approached to discuss their possible participation in the study. Patients will be given a Patient Information Sheet to read and time to consider their participation in the study. If they are happy to participate they will attend for two Study Visits, 7 to 14 days apart. Written informed consent will be taken before any study procedures are conducted. As children under the age of 16 are included in this study, parent / guardian consent will be taken where appropriate.