The aim of this article is to inform practitioners about legal techniques and rationale regarding the area of most direct concern to them, namely, the legal liability of the DFO specialist. It summarizes legal concepts (fault, hazard, medical misadventure…), the difficulties involved in interpreting them and their application to actual situations (root resorption, relapsed crowding…). Our own area of expertise is Law and not the art of dentistry. As a result, this article does not claim to settle controversies or solve problems related to dental technique. It is based on available literature dealing with the topic in order to approach it from the point of view of the law.