Practicing evidence-based orthodontics means offering patients treatment, which complies with scientifically-established data. However, how can we assess what science has determined to be certain given the confusing welter of information made available to us? The search for proof is a process, which requires knowledge of clinical methodology. It aims to set up a hierarchical classification of scientific and clinical studies and to assess their validity. By taking into account these different levels of proof, clinicians are in a position to make informed decisions regarding their clinical procedures and are thus empowered to take control of their learning process and the development of their skills.