The document discusses extraction in orthodontic treatment. It provides reasons for extraction such as to relieve crowding or correct skeletal problems. It discusses alternatives to extraction like arch expansion or jaw surgery. It describes different types of extractions like balancing, compensating, serial extractions. Factors influencing extraction choice are discussed like arch length discrepancy, tooth condition, malposition. Common teeth extracted are first premolars to relieve crowding in the front. Conditions for extracting other teeth like incisors, canines, molars are outlined.