 Participants in the study will be patients, who are in orthodontic treatment or will start orthodontic treatment; subjects must have full fixed appliances, with brackets bonded to the buccal surfaces of the maxillary and mandibular incisors, canines and first bicuspids. Subjects will be of moderate or high caries risk according to Caries Risk Assessment and ATP Adenosine triphosphate bacteria testing. Subjects will present with at least two active white spot lesions on hisher anterior teeth at the start of the study. The age limitation is 11 years. 