The present invention relates to an orthodontic appliance for use in the treatment of dental malocclusion.
The newest and the most effective method of orthodontic treatment, the main purpose of which is to treat dental malocclusion, is the technique of firmly fixing a bracket to each tooth and inserting and fixing a U-shaped wire into these brackets in order to correct a malalignment of the teeth by the elastic force of this wire. For example, as shown in FIG. 2, when the upper jaw central incisor (1) protrudes abnormally toward outside as shown by the solid line, it is corrected to the state shown by the broken line, by a method in which a band (2) is applied to each tooth (1) as shown in FIG. 1 and brackets (3) are welded to the outsides of these bands (2), i.e. to their labial surfaces or buccal surfaces, then a curved orthodontic wire (4) is fixed to these brackets (3) to correct teeth malalignment by the elastic force of this wire (4). As examples of this method, there are the ribbon arch technique, the edgewise technique, the Begg technique, the universal technique, etc. Among them, the brackets of the edgewise technique are, as shown in FIG. 3, composed of a flange (5) like a metal net or a plate and the tip (6) is attached to this flange (5). A fixing groove (7) is formed in the tip (6), so that a rectangular wire (4) may be inserted horizontally. Wings (8) are formed on both sides of the groove, and a ligature wire (9) retains the wire 4 in the groove. In the Begg technique, brackets (3) are also composed of the flange (5) and the related tip (6), as shown in FIG. 4, but the fixing groove (7) is formed so that a wire (4) may be inserted vertically from the opposite side of the occlusal plane. In addition, a slot is made for insertion of a lock pin (10) shown by the broken line. This pin is inserted from the gingival side and the protruding lower edge of the inserted lock pin (10) is bent and fixed. The ribbon arch technique and the universal technique similar to the edgewise technique or the Begg technique.
The main disadvantage of these conventional methods is that the bracket (3) and wire (4) are visible clearly from the outside of the mouth when the mouth is opened, because the brackets (3) are bonded or welded to the outer surfaces of teeth (1) i.e. their labial or buccal sides. This detracts from the facial beauty of the patient and, accordingly, imposes a considerable psychological burden on the patients.
In conventional orthodontic treatment, there are some methods for treating malocclusion from the lingual or palatal side. Those are the lingual arch appliance or the palatal plate appliance. Those methods push several teeth simply from the inside by the auxiliary spring attached to the lingual arch or plate. Therefore, the cases which can be treated by those techniques are limited. Accordingly satisfactory results are not obtained in the treatment of all teeth. Neither is it possible to use the conventional bracket itself by bonding same to the inside surface of the teeth. For example, it is not only extremely difficult to bond the bracket for the edgewise technique or Begg technique to the inside surface of the teeth, but also insertion of a wire into the grooves of brackets from the gingival side, fixation by the ligature wire, and insertion and fixation of lock pins into brackets are extremely difficult or impossible. The same difficulties also exist in the ribbon arch technique or the universal technique.