Clinical application of a lingual retractor with temporary anchorage devices (TADs) for patients with lip protrusion and anterior open bite

Abstract

Anterior open bite (AOB) is considered one of the most difficult malocclusions to correct and achieve successful and stable results. Various treatment approaches have been proposed for the treatment of AOB in adults. Intrusion of the entire maxillary dentition is necessary for AOB patients with severe incisor exposure. In previous reports, a labial appliance with temporary anchorage devices (TADs) implanted in various positions has been used to achieve total intrusion of the maxillary dentition. This article describes the design and biomechanics of an anteroposterior lingual retractor (APLR) to attempt retraction of anterior teeth and total intrusion of maxillary dentition after premolar extraction in patients with both lip protrusion and AOB and the functions of each component of APLR is considered. When force is applied between the anterior lever arm of the APLR and a TAD in the midpalatal area, the anterior teeth are intruded and retracted with torque control. Because the direction of the APLR force and the guide bar are not parallel, intrusive force is generated in the posterior teeth. Due to this total intrusion of the maxillary dentition, the mandible is rotated counterclockwise, improving AOB with severe incisor exposure. Various cases are presented in which APLR was applied to AOB patients, and the clinical considerations behind the treatment are explained in detail.