A THREE-DIMENSIONAL (3D) COMPARATIVE ASSESSMENT OF THE DENTOSKELETAL EFFECTS OF CLEAR ALIGNERS VERSUS TEMPORARY ANCHORAGE DEVICE (TAD)-ASSISTED POSTERIOR INTRUSION IN ADOLESCENTS WITH ANTERIOR OPEN BITE. A SINGLE-CENTER, RETROSPECTIVE, COHORT STUDY.

Anterior Open Bite (AOB) is a malocclusion characterised by the absence of overbite and contact between upper and lower incisors in centric occlusion. AOB prevalence worldwide has been reported to be approximately 5-6%, with a higher occurrence in certain ethnic groups. Management of AOB malocclusion in growing patients varies and the armamentarium of conventional clinical practice includes habit cessation devices such as tongue crib and spurs, activators, and removable or fixed posterior bite blocks aimed at controlling tongue posture and posterior eruption respectively. Alternative methods for the correction of AOB include intrusion of posterior teeth using skeletal anchorage through temporary anchorage devices (TADs) and clear aligner therapy (CAT). The current literature indicates that TAD assisted molar intrusion induces open bite closure through mandibular counter-clockwise rotation of up to 3.9 degrees. It has been suggested that clear aligners produce changes in the vertical dimension through a bite-block effect, facilitating counter-clockwise autorotation of the mandible and improving skeletal open bite. A recent study on adult patients concluded that reductions in AOB with CAT are largely a result of 1mm maxillary and mandibular incisor extrusion with some increases also noted in their lingual inclination, particularly in the maxilla. Most studies to date rely on two-dimensional (2D) cephalometric analyses of AOB treatment in both non-growing and adult patients. The aim of the present study was to compare the skeletal and dentoalveolar effects of CAT versus TAD-assisted intrusion of maxillary posterior teeth in growing adolescents with AOB using three-dimensional (3D) imaging. The null hypothesis assumed that there were no statistically significant differences in skeletal and dentoalveolar changes between the two groups. Additionally, the occlusion of the CAT group was assessed with the American Board of Orthodontists Objective Grading System (ABO-OGS) in order to provide evidence of the quality of final occlusion achieved with CAT.