Comparison of subperiosteal, short, and standard endosseous implants in the severely atrophic edentulous mandible: a three-dimensional finite element stress analysis study

Reconstruction of the severely atrophic edentulous mandible without complex augmentation remains a clinical challenge. With advances in digital design and fabrication, alternative implants such as short endosseous and subperiosteal implants have emerged as viable options. This study aimed to evaluate and compare the stress distributions in bone and implants under functional forces using three-dimensional finite element analysis (3D-FEA). A virtual model of a severely atrophic mandible was constructed based on tomographic data. Three implant configurations were designed and applied to the interforaminal region: short (6 mm) and standard (10 mm) endosseous implants, and a custom-designed subperiosteal implant made of grade 5 titanium. Each model was subjected to 100 N vertical and 50 N horizontal loads. Principal stresses in cortical bone and Von Mises stresses in implants were analyzed using 3D-FEA. Short and standard endosseous implants exhibited comparable stress levels in both cortical bone and implant surfaces. Subperiosteal implants showed higher Von Mises values but presented a more homogeneous stress distribution. Despite increased stress, values remained below material yield limits. Compressive stresses dominated in cortical bone across all models, with distal implant sites showing higher tensile loads. In atrophic mandibles, short and standard implants appear biomechanically favorable without requiring bone augmentation. Subperiosteal implants, despite higher stress levels, may still be a feasible alternative due to improved anatomical fit provided by CAD/CAM technology.