Impact of dental and zygomatic implants on stress distribution in maxillary defects: a 3-dimensional finite element analysis study

The aim of this study was to evaluate the stress distribution in the bone around dental and zygomatic implants for 4 different implant-supported obturator prostheses designs in a unilaterally maxillary defect using a 3-dimensional finite element stress analysis. A 3-dimensional finite element model of the human unilateral maxillary defect was constructed. Four different implant-supported obturator prostheses were modeled; model 1 with 2 zygomatic implants and 1 dental implant, model 2 with 2 zygomatic implants and 2 dental implants, model 3 with 2 zygomatic implants and 3 dental implants, and model 4 with 1 zygomatic implant and 3 dental implants. Bar attachments were used as superstructure. A 150-N vertical load was applied in 3 different ways, and von Mises stresses in the cortical bone around implants were evaluated. When the models (model 1-3) were compared in terms of number of implants, all of the models showed similar highest stress values under the first loading condition, and these values were less than under model 4 conditions. The highest stress values of models 1-4 under the first loading condition were 8.56, 8.59, 8.32, and 11.55 Mpa, respectively. The same trend was also observed under the other loading conditions. It may be concluded that the use of a zygomatic implant on the nondefective side decreased the highest stress values, and increasing the number of dental implants between the most distal and most mesial implants on the nondefective side did not decrease the highest stress values.