Effect of orthodontic treatment with premolar extractions on occlusal planes: A retrospective study.

Compared to the non-extraction group, there were more increases in the AOP-SN and AOP-POP angle and more posterior flattening in patients with four premolar extractions despite different types of dentoskeletal malocclusion, which were correlated to the change of variables in sagittal and vertical dimensions such as Wits and FHI.