Biomechanical three-dimensional finite element analysis of prostheses retained with/without zygoma implants in maxillectomy patients

The objective of this study was to analyze the stress distribution on zygoma implants and their supporting bones, superstructures and abutments under occlusal loads after maxilla reconstruction with prostheses. Four three-dimensional (3D) finite element models (FEMs) were constructed based on computed tomography (CT) data. One model of normal structure was constructed (Model 1) and three models of defects were simulated and restored with conventional prosthesis, one and two zygoma-implant-retained prostheses respectively (Models 2–4). Vertical and lateral loads of 150 N were loaded and the stresses distribution were observed and compared. The stresses distributed along the three mechanical pillars of maxillofacial parts in Model 1, which concentrated at the superstructure at Model 2. The zygoma implant can reduce the stresses at clasps and abutments in Model 3, while two zygoma implants can well share the stresses of affected side in Model 4. The distribution of stresses on prostheses were more rational with the help of zygoma implants which can share the stresses on the affected side adequately, so that it is fit for the reconstruction of unilateral maxilla defects.