Considered from the perspective of the finesse and skill they require of those who practice them, each of the existing trades has its own specificity. However, by referring to literature on expertise and talent7, we realize to what extent the patterns of the acquisition of expertise and its implementation can have invariants among the different trades. Human expertise has been studied in depth, among others, by cognitive sciences, psychology and neurosciences. After exposing the notions of domain of expertise, perceptual-cognitive and sensory-motor competence, the neurobiological and cognitive mechanisms of expertise demonstrating the importance of long-term memory in the acquisition of expertise, for example, by reference to the concept of chunking. We will seek to determine the characteristics of the orthodontist as an expert, the implications of this quality for the expert's training process, the importance of clinical experience, the extent to which the expert can trust his/her intuition (clinical sense) in his/her daily practice and the paradigm shift constituted by the digital transition, which requires new expertise in the field of developing spatial mental models of 3D structures.