Biomechanical evaluation of PEEK, titanium, and stainless steel IZC screws in maxillary arch distalization: A finite element analysis approach

Background : Maxillary arch distalization is a key strategy in the non-extraction management of Class II malocclusions. Infrazygomatic crest (IZC) screws serve as reliable extra-alveolar anchorage units in such treatments. The choice of screw material significantly influences biomechanical performance, yet comparative data on commonly used materials polyether ether ketone (PEEK), stainless steel, and titanium remain limited. Aims and Objectives : To evaluate the influence of hypothetical material substitution on stress distribution and deformation patterns during maxillary arch distalization by assigning PEEK, titanium, and stainless-steel material properties to an IZC screw of standardized geometry using finite element analysis. Materials and Methods : Three-dimensional finite element models of the maxillary arch were constructed from CT scan data. CAD software (CATIA V5 R19) and ANSYS Workbench R17.2 were used to simulate en-masse distalization. Identical boundary and loading conditions, including a bilateral 200-g retraction force, were applied to all models. A standardized IZC screw geometry was maintained across the models as a controlled hypothetical material-substitution approach, with material-specific mechanical properties assigned for PEEK, titanium, and stainless steel. Von Mises stress in the periodontal ligament (PDL), dentition, IZC screw, and surrounding bone, together with total deformation of the dentition and screw, was evaluated and compared. Results : PEEK exhibited the highest PDL stress (0.026515 MPa) and the greatest maximum total screw deformation (25.192 µm). Stainless steel demonstrated the highest internal screw stress (16.854 MPa) and the lowest maximum total screw deformation (1.2119 µm). Titanium showed intermediate maximum screw deformation (1.8056 µm) and the highest surrounding-bone stress (3.1641 MPa). Stress within the maxillary dentition was nearly identical across the three material models. Conclusion : Under the standardized conditions of this hypothetical material-substitution model, screw material influenced the predicted stress and deformation patterns. Stainless steel exhibited the lowest screw deformation, PEEK demonstrated the greatest deformation, and titanium produced the highest surrounding-bone stress. These findings are specific to the standardized screw geometry and should not be interpreted as direct evidence of comparative clinical anchorage performance.