Extraction of second premolars instead of first premolars is considered when the second premolars are severely carious because it allows preservation of the healthier first premolars, which better maintain occlusion and arch integrity. Removing a tooth with extensive decay prevents potential infection and complications, while maintaining teeth that are structurally sound aids in effective orthodontic space closure. This approach minimizes the risk of further dental morbidity and optimizes surgical outcomes. Extraction of non-carious teeth simply for rotation or impaction is not standard unless other clinical indications exist.

Reference: Sabiston Textbook of Surgery, 21st Edition.