Clinical outcomes of arch expansion with Invisalign: a systematic review

Objective: To assess the scientific evidence related to the clinical outcomes of Invisalign therapy in controlling orthodontic tooth movement. Materials: and Methods: An electronic search was conducted in Pubmed，Cochrane Library，Web of Science，Embase，and Scopus from November 2015 to November 2022 to identify all articles. Methodological shortcomings were highlighted and the quality of the studies was ranked using the Cochrane Tool for Risk of Bias Assessment. Results: : Three prospective, and twelve retrospective studies were included. Besides, the risk of bias was moderate for thirteen studies and unclear for the others. There’s statistically significant difference between the prettreatment and posttreatment arches. The average expansion was significantly different from that predicted for each type of tooth in both the maxilla and mandible. Furthermore, the efficiency decreased from the anterior area to the posterior area in the upper arch. Conclusion: Despite the fact that arch expansion with Invisalign® is not ideally predictable, clear treatment is considerable option to resolve dentition crowding. The efficacy of expansion performs greatest in the premolar area. More researches focusing on the treatment outcome with different materials of aligners should be conducted in the future. Overcorrection should be considered when planning arch expansion with Invisalign. In maxilla, the expansion rate decreases from anterior to posterior. In maxilla, presetting sufficient buccal root torque of posterior teeth may result in better efficiency of expansion.