Biomechanical assessment of zygomatic implants in clinical rehabilitation scenarios: A finite element and fatigue analysis.

OBJECTIVES: This study utilizes contemporary placement approaches and implant design to investigate zygomatic implants' biomechanical behavior and fatigue lifetime in clinical contexts. METHODS: A commercially available zygomatic implant assembly and an ex vivo skull were subjected to computed tomography. Three-dimensional models representing intra-sinus, extra-sinus, and extramaxillary configurations were constructed. The finite element analysis (FEA) was executed with vertical, lateral, and masseteric loads applied simultaneously. Von Mises stress served as the failure criterion, with data collection on implant fixtures, abutments, connector screws, and simulated bone structures. The analysis included peak stress locations, contour plots illustrating stress distribution, and fatigue limit assessments for implant components. RESULTS: Results revealed lower stress concentrations in mesial implant components compared to distal ones. The extra-sinus approach showed lower stresses in most prosthetic components. Peak stress concentrations in the maxillary bone layers (ranging from 25 to 27 MPa) were primarily localized at the alveolar ridge's crest at the zygomatic implant entrance point. On the zygomatic bone, the peak stresses were in the interface with the distal implant and ranged from 12 to 26 MPa. The in silico fatigue testing demonstrated an equally high fatigue lifetime of the implant components in all the approaches analyzed. SIGNIFICANCE: Because of additional clinical advantages, the extra-sinus approach was considered the optimal reconstruction method when patients' anatomy permits its application. Given the limited long-term clinical data on the latest implant designs and placement techniques, these findings provide valuable insights into the biomechanical performance of zygomatic implants and offer guidance for clinical practice.