Biomechanical evaluation of different implant configurations in the severely atrophic maxilla: A three-dimensional...

The aim of this study was to comparatively evaluate the stress distribution in cortical bone, trabecular bone, implants, and prosthetic superstructure under vertical and oblique loading conditions in severely atrophic maxilla with different implant combinations using three-dimensional Finite Element Analysis (FEA).

A three-dimensional maxillary model was generated from anonymised computed tomography data, and four implant configurations were designed: Model 1 (quad zygoma), Model 2 (transnasal + zygomatic), Model 3 (zygomatic + pterygoid), and Model 4 (transnasal + zygomatic + pterygoid). Cortical and trabecular bone, implants, and prosthetic components were modelled assuming linear elastic material properties. Two loading scenarios were applied: vertical loading (total 450 N) and oblique loading at 30° (total 150 N). Maximum (Pmax) and minimum (Pmin) principal stresses in cortical and trabecular bone and von Mises stresses in implants and prosthetic frameworks were calculated.

Under vertical loading, the highest cortical Pmax was observed in Model 3 (23: 10.263 MPa), whereas lower values were found in transnasal-containing models (Model 2: 7.530 MPa; Model 4: 7.788 MPa). Similarly, the highest implant von Mises stress occurred in Model 3 (23: 82.152 MPa) and the lowest in Model 2 (61.046 MPa). A comparable stress distribution pattern was observed under oblique loading. In all models, maximum stresses were concentrated in the crestal cortical bone and implant neck region and remained within physiological limits.

Implant configuration significantly influences peri‑implant stress distribution in severely atrophic maxilla. The use of transnasal implants reduced anterior stress levels, while the addition of pterygoid implants contributed to more homogeneous load transfer along the arch.