Abstract
Premolar extraction is a widely used orthodontic intervention to manage crowding, correct malocclusion, and achieve balanced facial aesthetics. Several factors, including the severity of crowding, facial profile requirements, and anchorage demands, influence the choice between extracting first or second premolars. However, this decision is complicated by the distinct impacts each extraction pattern has on tooth movement, soft tissue profile, vertical dimension, and third molar eruption. The debate continues over which extraction pattern provides more favorable outcomes, highlighting the need for a thorough understanding of their respective advantages and limitations. This review aims to comprehensively analyze the effects of first versus second premolar extractions on anchorage loss, tooth movement, vertical dimensions, lip position, and third molar eruption in order to provide evidence-based insights for optimizing orthodontic treatment outcomes and guiding future research. The findings demonstrate that both extraction patterns have distinct clinical implications and should be selected based on individual patient characteristics, including crowding severity, facial esthetics, anchorage needs, and third molar considerations. Clear aligner therapy requires particular attention to anchorage control, especially following second premolar extraction. Further longitudinal studies are recommended to strengthen clinical guidelines and improve treatment predictability.