In the 1930s, creative thinkers in orthodontics began to more openly question the status quo. Apprenticeships had given way to formal instruction, and proprietary schools bowed to graduate university programs, including some taught or headed by women. The MD degree was gradually replaced by the MS as the focus of orthodontics zoomed out from teeth to the total patient. Angle’s dogmatic stance against extraction was challenged successfully by his last disciple, Tweed, and another of Angle’s pupils, Broadbent, developed that century’s most important diagnostic aid, the cephalometer, which opened the door to Brodie’s landmark growth studies and Downs’s cephalometric analysis. Dentistry’s first specialty organization, the Society of Orthodontists, was formed in 1900, and the first specialty journals appeared.