Biomechanical comparison of titanium and Y-TZP subperiosteal implants in atrophic maxilla: a finite element study

The aim of this study was to evaluate the biomechanical behavior of subperiosteal implant systems manufactured from titanium and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) materials under different implant thicknesses and screw diameters using three-dimensional finite element analysis (FEA).

Eight FEA models were generated from maxillary geometry obtained using computed tomography (CT). Two implant materials (Titanium and Y-TZP), two implant thicknesses (1.0 mm and 1.5 mm), and two screw diameters (1.5 mm and 2.0 mm) were evaluated. Three loading conditions were simulated: bilateral vertical loading of 150 N on premolars and first molar, unilateral oblique loading of 100 N at 30°, and bilateral vertical loading of 150 N on the incisors. Total displacement values, maximum and minimum principal stresses in the bone; Von Mises stresses in the bone, subperiosteal implant, abutment, and metal framework were analyzed.

Increasing implant thickness reduced stress levels in the bone while increasing stresses within the subperiosteal implant and metal framework. Larger screw diameters decreased stress in the bone and implant but increased stress concentration in the metallic substructure. The higher elastic modulus of Y-TZP reduced stress transmission to the bone; however, higher stresses were observed within the implant body and framework.

Implant thickness, screw diameter, and material stiffness influenced the biomechanical behavior of subperiosteal implants. Both materials produced bone stress values below thresholds associated with bone resorption. Y-TZP demonstrated favorable stress distribution in terms of reduced bone stress due to its material properties. In vitro, in vivo, and clinical studies are required to validate its long-term biomechanical performance and clinical applicability in subperiosteal implant systems.