it is important to note that tweed's philosophy was different than edward angle, his mentor. edward angle practiced strictly without extraction of teeth to achieve harmonious occlusion. tweed believed that extracting teeth lead to a more harmonious profile than what angle achieved in his practice. in 1940, tweed took 100 patients and treated them without extractions. when their treatment had failed, he then treated them with extractions for no additional fee. he presented his findings at the aao meeting. according to proffit et al., under the leadership of charles tweed, extraction of teeth was reintroduced into orthodontics in the 1940s and 1950s to enhance facial esthetics and occlusal relationships.