Invisalign - a concept for the prevention of white spot lesions in teenaged orthodontic patients?

INTERVENTION: Two groups of patients (male and female, aged 13‐19 years) will be randomly allocated into one of two arms: 1. Group 1 will consist of 30 patients. All of these patients receive a traditional multi‐bracket appliance for orthodontic treatment. 2. Group 2 will consist of 30 patients. All of these patients receive Invisalign therapy for orthodontic treatment. CONDITION: Malocclusion ; Oral Health PRIMARY OUTCOME: 1. Macroscopic characterization (presence, frequency, and severity) of white spot lesions at baseline, after 6 months, and after 12 months of orthodontic treatment. The severity of disease will be rated according to Gorelick's classification:; Grade 0: no visible white spot lesions on clinical investigation; Grade 1: minor white spot lesions; Grade 2: severe white spot lesions; Grade 3: white spot lesions with cavitation; 2. Determination of fluorescence, size and lesion depth and the bacterial acitivity of white spot lesions by means of quantitative light‐induced fluorescence measurement (QLF) at baseline, after 6 months, and after 12 months of orthodontic treatment. SECONDARY OUTCOME: Determination of fluorescence, size and lesion depth and the bacterial activity of white spot lesions by means of quantitative light‐induced fluorescence measurement (QLF) after active orthodontic treatment and 6 month later. INCLUSION CRITERIA: 1. Orthodontic indication for a vestibular multi‐bracket appliance or 2. The need and desire to receive Invisalign therapy 3. Persons aged 13‐19 years (teenagers) with fully erupted and visible teeth before treatment 4. No white spot lesions at baseline/no caries 5. Good oral hygiene 6. Written informed consent