ORTHODONTIA, a special department of dentistry con cerned with the prevention and correction of irregular and of mal posed teeth. Orthodontic treatment is usually effected by means of the spring force of delicate wires attached to the teeth. The earliest attempt in the literature at systematic treatment of orthodontia was by Fauchard in 1728. In 1836 Kneisel published a special work on the subject. Between these two it was variously treated by several writers in the field of mechanical dentistry (Bunon Bourdet 1757; Fox 1803; Delabarre 1819). At the beginning of the loth century in America orthodontia emerged from the general field of mechanical dentistry as a recognized specialty. Its advent was heralded by the appearance of many "systems of regulating." These "systems" were marketable com binations of mechanical appliances designed to effect various move ments of the teeth, and were identified by the names of their in ventors (Angle, Case, Jackson et al). While this period of the exploitation of apparatus undoubtedly was a great stimulus to the development of technique, the literature which it evoked took the form of personal opinion rather than the presentation of scientific evidence. Expert technicians soon demonstrated the
limitations of the mechanical conception of the subject where upon interest centred in its biological aspect. Since then the results of treatment have been more satisfactory. Great advances have been made in America where specialization is more common while the conservative influence of the dental profession in Great Britain and European countries has acted as a stabilizing force in its growth. The condition of irregular and malposed teeth, i.e., malocclusion, may be caused by bad diet in both its chemical and physical aspects (Howe, McCollum, Mellanby). Habits of in fancy and childhood as thumb-sucking, tongue-biting and mouth breathing, and mutilations from trauma and disease are also important causes. In fact any abnormal function in or about the mouth when persisted in may result in irregular and malposed teeth. (A. L. J.)