Orthodontic tooth movement induces biological responses in periodontal tissues that can be reflected by changes in gingival crevicular fluid (GCF). This study aims to evaluate temporal changes in GCF volume during orthodontic treatment with clear aligners and conventional fixed appliances. GCF samples will be collected from the buccal site of tooth 12 and the palatal site of tooth 16 at baseline, 1 hour, 1 day, 1 week, and 1 month after appliance placement. The findings of this study will help to better understand periodontal tissue responses associated with different orthodontic treatment modalities.