Inclusion Criteria:  Planned to receive orthodontic treatment with upper and lower fixed orthodontic appliances (braces) either alone or following a period of functional appliance treatment. 11-16 years of age inclusive at the start of the fixed orthodontic appliance treatment. All genders. Fit and well with no chronic disease necessitating regular hospital follow-up at hospital. Willing to participate  Exclusion Criteria:  Significant disabilities that may affect manual dexterity; Any medical complication that would contraindicate the use of the fluoride treatments or milk products; Previous orthodontic treatment except Phase I functional appliance treatment; From areas that have fluoridated water supply*; Full coronal coverage restorations; More than 2 missing anterior teeth; Showing signs of systemic illness e.g. fever, cough, loss of taste/smell; Any abnormality of face, lips e.g. cleft lip and/or palate or craniofacial abnormality or soft tissues of the mouth e.g. aphthous ulcers or connective tissue disorder.