Comparison of Different Clear Aligner Attachment Positions on Maxillary Posterior Teeth Intrusion with Buccal and Palatal Mini-Screw Anchorage System: A Finite Element Study

Abstract ObjectiveThis study evaluates the effects of intrusion of the maxillary posterior teeth by the use of clear aligner (CA) with buccal and palatal mini-screw anchorage system.MethodsCone-beam computed tomography images of a male patient with a skeletal Class I without any craniofacial anomalies were selected. The maxillary arch was divided into two symmetric sections Model A (right side) and Model B (left side) to compare the effect of buccal and palatal attachment placements using a mini-screw-supported closing coil spring. Finite element analysis (FEA) will assess stress distribution, displacement and mechanical efficiency during posterior teeth intrusion with different attachment positions.ResultsIn Model A, the first premolar showed a buccal crown tipping and mild extrusion; the second premolar had similar displacement but with a mild vertical eruption. In Model B, the first premolar exhibited palatal crown tipping, buccally rooted torque and slight intrusion; the second premolar presented with a palatal drift, with less distalization. The first molar in Model A showed minimal mesial movement with a slight buccal crown tipping and extrusion. In Model B the first molar had better intrusion control with palatal root torque due to buccal anchorage.ConclusionIn Model A the palatal screw experienced significantly less stress with minimal displacement. Indicating that in Model A provided a controlled distal tipping, palatal root movement and anterior intrusion, with more efficient force redirection with lower stress and superior anchorage stability. While in Model B absorbed much higher loads and showed greater displacement.