Impact of Initial Lip Asymmetry on Long-Term Lip Symmetry in Unilateral Cleft Lip and Alveolus Patients: An Orthodontic Perspective

tests with effect sizes (Cohen's dz) and false discovery rate adjustment were used, and importance scores were used to visualize the combined magnitude and robustness of changes.ResultsOverall lip symmetry tended to improve from T1 to T2 in both rest and smile conditions. Measure 2 (peak of Cupid's bow to oral commissure distance) and Measure 6 (lower lip width) exhibited negative Δ values with moderate effect sizes (dz = 0.39-0.42) in unadjusted analyses. After adjustment for multiple comparisons, no comparisons remained statistically significant; however, effect-size patterns suggested consistent, moderate improvement in symmetry in regions around the Cupid's bow.ConclusionsInitial lip asymmetry influences long-term symmetry changes in UCLA patients. Quantitative assessment of region-specific symmetry changes may support interdisciplinary planning focused on individualized soft-tissue outcomes.