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

White spot lesions (WSLs) are a common complication of orthodontic treatment and represent the earliest stage of enamel demineralization. Although clear aligner therapy is generally associated with a lower risk of WSL development than fixed appliances, enamel demineralization may still occur during treatment. Chitosan nanoparticles possess antimicrobial properties and have shown potential for preventive dental applications. This study investigated the effectiveness of chitosan nanoparticle-coated clear aligners in limiting enamel demineralization during orthodontic treatment.

A prospective two-arm parallel-group randomized controlled clinical trial was conducted on 53 patients (18-29 years) undergoing clear aligner therapy. Participants were randomly allocated into two groups: conventional clear aligners (control) and chitosan nanoparticle-coated clear aligners (experimental). Three participants were lost to follow-up, and 50 patients (25 per group) were included in the final analysis. Chitosan nanoparticles were prepared using ionic gelation and applied to aligner surfaces following atmospheric plasma treatment. Surface characterization was performed using profilometry, scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDAX). White spot lesions were assessed at baseline and after six months using quantitative light-induced fluorescence (QLF)

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.
• Poor oral hygiene or presence of active periodontal disease, including gingivitis or periodontitis.