Effects of orthodontic mini-implant position in the dragon helix appliance on tooth displacement and stress distribution: a three-dimensional finite element analysis

Abstract

Objective: The purpose of this study was to investigate the stress distribution on the orthodontic mini-implant (OMI) surface and periodontal ligament of the maxillary first and second molars as well as the tooth displacement according to the OMI position in the dragon helix appliance during scissors-bite correction. Methods: OMIs were placed at two maxillary positions, between the first and the second premolars (group 1) and between the second premolar and the first molar (group 2). The stress distribution area (SDA) was analyzed by three-dimensional finite element analysis. Results: The maximal SDA of the OMI did not differ between the groups. It was located at the cervical area and palatal root apex of the maxillary first molar in groups 1 and 2, respectively, indicating less tipping in group 2. The minimal SDA was located at the root and furcation area of the maxillary second molar in groups 1 and 2, respectively, indicating greater palatal crown displacement in group 2. Conclusions: Placement of the OMI between the maxillary second premolar and the maxillary first molar to serve as an indirect anchor in the dragon helix appliance minimizes anchorage loss while maximizing the effect on scissors-bite correction.

Diagnosis and Management of a Unilateral Posterior Open Bite Using a Temporary Anchorage Device (TAD): Case Report and Review of the Literature

“…When such open bites are skeletal and the patient declines surgery, then an orthodontic option for treatment is opted for which needs more time and patient cooperation [13]. Studies have recommended TADs for the provision of anchorage in the extrusion and intrusion of posterior teeth [7,10,14,15]. This mechanism had been shown to close POB and reduce facial height without any form of surgical intervention [10,16].…”

Torque control during lingual anterior retraction without posterior appliances

“…In this study, the teeth, alveolar bone, and periodontal spaces were assumed to be isotropic and homogeneous linear elastic bodies, and the material properties of the elements were based on values for Young's modulus and Poisson's ratio, according to previous studies (Table 1). 19-21 In the system studies, we assignedd the X-axis to the median-lateral direction, the Y-axis to the anterior-posterior direction, and the Z-axis to the coronal-apical direction. Furthermore, we defined +X as the left central incisor direction, +Y as the labial (anterior) direction, +Z as the apical direction, and the X - Y plane as the occlusal plane of the teeth.…”

Evaluation of Stability of Surface-Treated Mini-Implants in Diabetic Rabbits

“…With skeletal anchorage such as osseous dental implants, miniplates, miniscrews, or microscrews, clinicians can expect reliable anchorage while depending less on patient compliance [ 1 – 7 ]. Most current orthodontic mini-implants have untreated screw surfaces, and mini-implants achieve primary stability through mechanical retention [ 5 , 8 ]. In the field of prosthodontics, surface-treated dental implant is preferred due to its improved osseointegration [ 9 – 12 ].…”