Open-Bite Correction Using a Mid-Palatal TAD with an Intrusion TPA: Anteroposterior Position of TAD

Abstract

Mechanics using a mid-palatal temporary anchorage device (TAD) and an intrusion transpalatal arch (TPA) were applied to correct the open bites. Two different intrusion patterns could be obtained according to the anteroposterior position of mid-palatal TADs. When the TAD was placed posterior to the first molar, the posterior teeth were intruded (“posterior intrusion”), and the open bite was corrected efficiently. This is commonly used in most open bites. However, sometimes, in an open bite with a gummy smile, intrusion of the maxillary anterior teeth, as well as the posterior teeth, may be necessary. In this case, the TAD was placed anterior to the first molar, and a “total intrusion” was obtained, including anterior intrusion. In conclusion, the intrusion pattern of the maxillary teeth differs depending on the anterior–posterior position of the mid-palatal TAD, necessitating posterior intrusion or Total intrusion.