This study used mixed-methods data mining to identify concepts related to dental students’ professional identity development and trace their evolution over time. Words in students’ reflections were clustered based on similarity of use (represented in a 50-dimensional word-embedding model); these concepts were characterized at three points in time by constructing co-occurrence networks of constituent words and inspecting representative sentences. Analysis of 4,069 reflection statements from 378 students over four years revealed twelve relevant concepts. Over time, students’ vision of Becoming a Professional showed increased emphasis on ethical practices, shifting focus from self-as-dentist to Providing the Best Patient Care. In addition to gaining Confidence through Progress to be a part of the Field of Dentistry, students also personalized their view of the profession, coming to Know Oneself as a Dentist and, at times, connecting this to their Life Vision. Implications for the theory, study and support of professional identity development are discussed.