Inclusion Criteria:  Participants in the study are children ages 12 and older, in good general health Children, requiring fixed orthodontic treatment (brackets) Children at high caries risk according to 'Oral disease risk assessment tool' accepted and used in the Department of Paediatric Dentistry, Faculty of Dental medicine, Medical University - Plovdiv, Bulgaria Children with untreated non-carious vestibular surfaces of the six maxillary anterior teeth of the permanent dentition (central and lateral incisors, canines) with ICDAS code 0 Verbal assent from the child willing to comply with all study procedures and protocol Obtained written informed consent by the patient's parent/guardian for participation in the study  Exclusion Criteria:  Children with systemic diseases that may affect oral health or oral microflora (such as diabetes, etc.) Children with medication intake that could affect the salivary flow or oral microflora (such as antibiotics, etc.) Children with mental or cognitive problems Patients with maxillary anterior permanent teeth affected by disturbances in the development of dental structures (hypoplasia, hypomineralization, fluorosis)