Comparative Evaluation of Stress Distribution and Displacement Using Three Different Mini-implant Diameters with Bicortical Anchorage in Bone-borne Palatal Expansion—A Finite Element Study

Objective Using three distinct mini-implant diameters with bicortical anchorage in palatal bone-borne expansion (mini-implant assisted rapid palatal expansion (MARPE)), the differences in stress distribution and displacement in the supporting bone and mini-implants are evaluated and compared. Materials and Methods A skull model was utilized to simulate maxillary expansion and to examine the von Mises stress distribution and displacement across three clinical scenarios involving bicortical mini-implants of varying diameters (1.6, 1.8, and 2.0 mm). Each scenario was analyzed using the finite element method (FEM) simulations to assess biomechanical behavior. Results The 1.6 mm mini-implant model showed higher stress concentrations around the implant area compared to the 1.8 and 2.0 mm models. The 2.0 mm bicortical anchoring model had a larger total displacement. Additionally, the stress within the expander during the initial 0.25 mm activation was observed to be highest in the 2.0 mm mini-implant. Conclusion Mini-implants with larger diameters, especially 2.0 mm, demonstrated greater biomechanical stability in bicortical anchorage applications. They contribute to improved force transmission, reduced risk of implant deformation, and more effective skeletal expansion, making them a favorable choice in adult palatal expansion treatments.