3D Finite Element Analysis of Quad Zygomatic, Transnasal, and Pterygoid Implants for the Rehabilitation of Patients with Severely Atrophic Maxillae.

PURPOSE: To compare the effects of different occlusal forces on quad zygoma, transnasal, and pterygoid implants in patients with severely atrophic maxillae using finite element analysis (FEA).

MATERIALS AND METHODS: CBCT data from patients with severely atrophic maxillae were gathered to create 3D FEA models. Three models were developed: Model 1 was a quad zygoma model with four zygomatic implants placed according to the extrasinus technique; Model 2 was a combination of one zygomatic implant placed using the extrasinus technique and one transnasal implant, with one pair on each side; and Model 3 used transnasal, zygomatic, and pterygoid implants. Two different forces were applied to the models: a 150-N vertical force at the first premolar, second premolar, and first molar region and a functional force consisting of a 100-N vertical force combined with a 50-N horizontal force at the same locations. Stress values in the bone, implants, abutments, and prosthetic framework were evaluated.

RESULTS: Model 1 demonstrated the highest stress values on the implants, abutments, and prosthetic framework under both vertical and functional forces. Model 2 showed lower stress values compared with Model 1. Model 3 exhibited lower stress levels on the bone, implants, abutments, and prosthesis compared with the other models.

CONCLUSIONS: The use of transnasal implants with zygomatic implants presents an alternative to the use of the quad zygoma protocol. Additionally, in the model supported by pterygoid implants, the absence of cantilevers resulted in reduced stresses on the bone, implants, abutments, and prosthetic framework. We recommend the application of pterygoid implants alongside zygomatic and transnasal implants for long-term success and the prevention of biomechanical complications in the rehabilitation of severely atrophic maxillae.