Clear aligners have been shown to be effective in treating mild to moderate cases of both spacing and crowding. They work by applying controlled forces to the teeth, which leads to bone remodeling and gradual tooth movement. In spacing cases, aligners are particularly effective at closing small to moderate gaps, especially in the front teeth. For crowding, aligners can help resolve up to 6 mm of misalignment by expanding the dental arch, proclining the teeth, or using interproximal reduction (IPR) to create space. However, aligners have limitations when it comes to managing severe crowding or complex tooth movements such as significant root torque, vertical shifts, or rotation of certain teeth like canines. Their success also depends heavily on patient compliance, as they must be worn for 20–22 hours per day. Overall, aligners are a clinically proven and efficient option for addressing spacing and crowding problems in suitable cases, supported by studies from Rossini et al. (2015), Ke et al. (2019), and Papadimitriou et al. (2018). Rossini, G., Parrini, S., Castroflorio, T., Deregibus, A., & Debernardi, C. (2015). Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review. The Angle Orthodontist, 85(5), 881–889. https://doi.org/10.2319/061614-436.1 Ke, Y., Zhu, Y., & Zhu, M. (2019). A comparison of treatment effectiveness between clear aligner and fixed appliance therapies. BMC Oral Health, 19(1), 24. https://doi.org/10.1186/s12903-018-0695-z Papadimitriou, A., Mousoulea, S., Gkantidis, N., & Kloukos, D. (2018). Clinical effectiveness of Invisalign® orthodontic treatment: a systematic review. Progress in Orthodontics, 19(1), 37. https://doi.org/10.1186/s40510-018-0235-z