Stress Distribution of the Zygomatic Implants in Post-mucormycosis Case: A Finite Element Analysis

The aim of this study was to assess the stress distribution of the zygomatic implants in maxillectomy cases and to understand the long-term prognosis of this rehabilitation option using finite element analysis.

A three-dimensional finite element model was designed using computed tomography of a patient who underwent maxillectomy post-mucormycosis. Zygomatic implants and abutments were designed based on the manufacturer's design. Quad zygomatic implants were placed in the canine and premolar region into the zygomatic bone bilaterally. A prosthesis with an entire complement of teeth extending from the first molar teeth bilaterally was designed and attached to the multiunit abutments and zygomatic implants. Forces were applied to the zygomatic implants at six different locations bilaterally on the prosthesis which included occlusal and laterally directed forces on the central incisor region, canine region, and molar region using von Mises criteria. A three-dimensional finite element analysis was run, and maximum stress distribution was recorded at various loads. Statistical Package for Social Sciences for Windows version 22.0 Released 2013. Armonk, NY: IBM Corp., was used to perform statistical analyses. Kruskal-Wallis test was used to compare the mean stress values. Multiple comparisons of mean difference in stress values between force applications in implant were done using Dunn's post hoc test.

The maximum stress was observed at the distal head of the implant in the models. Minimum stress was observed at the apex of the implant in the models. The mean stress values based on force application in the bone and fixed prosthesis showed less significance when compared to the zygomatic implants which was statistically significant at p = 0.03.