The Effect of Nano Chitosan Surface Coating on White Spot Lesions Development in Clear Aligner Therapy Patients

Inclusion Criteria: * Patients presenting with mild to moderate malocclusion (sagittal, vertical, transverse discrepancies, or crowding) that could be treated using clear aligners within a maximum treatment period of one year and without the need for extraction therapy. * Medically healthy patients with no systemic diseases or medical conditions that could affect enamel integrity, salivary flow, oral hygiene status, or periodontal health. * Patients with no history of previous orthodontic treatment, dental trauma, or parafunctional habits such as bruxism. * Patients with good oral hygiene and absence of active periodontal disease, including gingivitis or periodontitis. * Patients willing to comply with the prescribed clear aligner wear protocol for a minimum of 22 hours per day. * Patients who agreed to participate in the study and signed the informed consent form. Exclusion Criteria: * Previous orthodontic treatment that could influence baseline enamel condition or white spot lesion assessment. * Presence of active carious lesions, cavitated lesions, severe enamel hypoplasia, or developmental enamel defects. * Extensive restorations on anterior teeth that could interfere with Quantitative Light-Induced Fluorescence (QLF) imaging and analysis. * Systemic diseases or medical conditions affecting salivary flow, enamel integrity, oral hygiene, or periodontal health. * Use of medications known to affect salivary secretion, enamel mineralization, or oral microbial balance. * Po…