At commencement of the study it will be recorded how long participants fixed appliances had been in situ, and all participants and clinicians will receive a questionnaire to determine their fluoride use, oral hygiene regime, diet and preventive interventions e.g. visits to hygienist, topical fluoride application, during their fixed appliance treatment. The participants dental records will be reviewed and any record of pre-existing developmental defects of enamel or WSLs will be documented. Participants will be asked to score their own perception of the appearance of their teeth, considering the presence of their WSLs, using a validated Visual Analogue Scale (VAS).