Background: Clear aligner therapy (CAT) has become increasingly popular as an aesthetic alternative to fixed appliances, yet its ability to achieve predicted tooth movement remains debated. The predictability of CAT—the agreement between ClinCheck-predicted and clinically achieved tooth positions—varies substantially across movement types and tooth types.

Objective:

This systematic review and meta-analysis aimed to quantify the predictability of tooth movement with clear aligners across different movement types (rotation, extrusion, bodily translation, and torque) and to compare treatment outcomes between CAT and fixed appliances. Methods: PubMed, Embase, Scopus, Cochrane Library, and Web of Science searched from inception to January 2026. Eligible studies compared predicted versus achieved tooth movement with clear aligners and reported quantitative accuracy outcomes. Random-effects meta-analyses pooled mean differences and accuracy percentages. Risk of bias was assessed using ROBINS-I and RoB 2. Certainty of evidence evaluated using GRADE.

Results: Twenty-seven studies (N = 2,847 patients) were included. Overall predictability varied significantly by movement type. Rotation was the least predictable movement (pooled accuracy 51.2%; 95% CI 44.8–57.6%), with canine rotation particularly unreliable (42.3%). Extrusion showed moderate predictability (58.9%; 95% CI 52.1–65.7%). Bodily translation demonstrated higher accuracy (68.4%; 95% CI 61.2–75.6%), though posterior movements were less predictable than anterior movements. Torque control showed substantial variability (prediction interval 31.2–72.8%). No significant difference was found in overall American Board of Orthodontics Objective Grading System scores between CAT and fixed appliances (mean difference 1.87; 95% CI −2.32 to 6.06; p = 0.38), though heterogeneity was high (I² = 90%).

Conclusion: Clear aligner therapy demonstrates movement-specific predictability, with rotation being least predictable and anterior bodily movement most predictable. Clinicians should consider overcorrection strategies for rotation and extrusion and anticipate refinement needs. The certainty of evidence is low to moderate, highlighting the need for standardized prospective studies.