An invisible tooth orthodontic device without a bracket, and a preparation method therefor. The invisible tooth correction device without a bracket is a brace (1) made of a polymer transparent elastic material. A reinforcing structure (2) is disposed on the lower edge of the brace (1). The reinforcing structure (2) is one or more sections of bulges like an undee curve. Because the reinforcing structure (2) is disposed on the lower edge of the invisible tooth orthodontic device without a bracket, the reinforcing structure (2) can reinforce the lower edge of the orthodontic device. When the reinforcing structure (2) is one or more sections of bulges, the reinforcing structure (2) can prevent the partial loss and tear of the orthodontic device. When the strengthening structure (2) is a section of enclosed ring-shaped bulge, the strengthening structure (2) can also enhance the overall orthodontic power of the orthodontic device, so that the orthodontic device provided with the strengthening structure (2) can also be used for expansion or contraction of the whole dentition. By means of the preparation method, the invisible tooth orthodontic device without a bracket and with a strengthening structure (2) can be accurately computed and prepared.La présente invention concerne un dispositif orthodontique à dents invisibles sans bracket, et son procédé de préparation. Le dispositif orthodontique à dents invisibles sans bracket est un appareil (1) constitué d'un matériau élastique transparent polymère. Une structure de renfort (2) est disposée sur le bord inférieur de l'appareil (1). La structure de renfort (2) est constituée d'une ou de plusieurs sections de bosses comme une sous-courbe. Comme la structure de renfort (2) est disposée sur le bord inférieur du dispositif orthodontique à dents invisibles sans bracket, la structure de renfort (2) peut renforcer le bord inférieur du dispositif orthodontique. Lorsque la structure de renfort (2) est constituée d'une ou de plusieurs
