According to the study by Tae-Woo Kim, Jon Artun, Faraj Behbehani, and Flavia Artese “a clinically significant reduction in the rate of impaction of maxillary and mandibular third molars in ex patients compared with non-ex patients. The mechanism might be that premolar extraction therapy is associated with an increase in the amount of mesial movement of the maxillary and mandibular molars and an increase in the eruption space for the third molars.”