| 摘要 |
<p>It is comprised of a plastic chinpiece with two screws in the superoexternal parts. Around said screws, is provided a 2 mm wire with a 9 cm rear branch which goes upwards by 1 cm and is introduced into a millimetered tube secured by means of a screw in order to regulate the height of the maxillary traction. It continues backwards to enter in the mouth, this branch being also mllimetered and having a length of 8 cm. It is terminated by a hook to get into the orthodontia bands. The force exerted by the rear strap (neck, medial occipital) is transmitted to the chin and, in turn, to the jawbone, thereby having the desired effects on the malocclusions of class III. An alternative is that the ascending branch terminates at the mouth corner in order to lock extra-oral elastics. In one way or the other, the user has the mandible biased backwards and the maxilla forwards.</p> |
