Efficacy of Anterior Tooth Simulations with Clear Aligner Therapy - A Retrospective Cohort study of Invisalign and Flash Aligner Systems

Purpose: The purpose of this study was to compare the efficacy of tooth movement between two clear aligner systems by comparing the predicted treatment outcomes versus actual outcomes achieved using a 3D best-fit algorithm. Materials & Methods: Clear aligner therapy (CAT) was used to treat 62 patients; n= 38 Invisalign (R) and n=24 Flash (R). The Invisalign group had a male to female distribution of 13:25 and a mean age of 35.5, while the Flash group had a male to female distribution of 6:18, with a mean age of 29.2. Differences in predicted versus achieved actual outcomes were compared using eModel Compare 8.1 software. Results: 1) Intra-group differences between predicted and achieved tooth movements for angular movements were statistically (P<0.05) and clinically (>2 degrees) significant with both treatment methods, except for tipping of maxillary and mandibular incisors for Flash (R) (<2 degrees). 2) Inter-group results demonstrated statistically significant differences in favor of Flash (R) for maxillary central incisor Tip (1.3 degrees), BL movements for maxillary canines (0.1mm), and mandibular central incisor Rotations (1 degrees). These did not exceed the threshold for the clinical relevance of 2 degrees or 0.5mm. Conclusions: There were no differences in clinical accuracy and efficacy between Invisalign or Flash aligner systems in achieving predicted tooth movement.