Biomechanical Behavior of Different Distributions of Zygoma and Pterygoid Implants in Rehabilitation of Severely Atrophic Posterior Maxilla: A 3D Finite Element Analysis

This study was aimed to evaluate 3-dimensional finite element analysis (FEA) of stress distribution in zygomatic and pterygoid implants in atrophic posterior maxilla. A 3D FEA model of an edentulous, atrophic maxilla was developed using cone-beam computed tomography (CBCT) scans. Four different implant configurations were evaluated: 2 zygomatic+2 pterygoid+3 anterior implants, 2 zygomatic+3 anterior implants, 2 zygomatic+2 pterygoid+2 anterior implants, and 2 zygomatic+2 anterior implants. Virtual implants were placed and a prosthetic superstructure was designed for each model. FEA was conducted to analyze stress distribution within the bone, implants, and prosthesis under simulated masticatory loads. Stress distribution in the peri-implant bone, abutments, and prosthetic framework was visualized through von Mises stress maps, while maximum principal stresses and micromotion were evaluated to determine implant stability and osseointegration potential. FEA revealed notable variations in stress distribution among the 4 models. Model 4 exhibited the highest peri-implant bone stress on the zygomatic left implant. Micromovement was lowest in model 4 and highest in model 2. Abutment-level stress analysis in model 3 showed the lowest stress on zygomatic implants and pterygoid implants, whereas model 4 recorded the highest stresses on zygomatic implants. Prosthetic framework stress was highest in model 2, while prosthetic superstructure stress showed minimal variation across models. Inclusion of pterygoid implants alongside zygomatic and anterior implants effectively reduces stress concentrations and micromovements in the atrophic maxilla, enhancing biomechanical stability and load distribution. Models without pterygoid implants showed increased stress on zygomatic implants, potentially compromising long-term stability.