Investigation of the stresses on pterygoid and zygomatic implants used in atrophic maxilla rehabilitation by finite element analysis.

Abstract

Background: This study aims to compare stresses from vertical and oblique forces on pterygoid and zygomatic implants, combined with dental implants, in a atrophic maxilla using finite element stress analysis.

Material and methods: A computed tomography scan was used to create a geometric model of a completely edentulous adult maxilla. The maxillary bone was scanned using cone beam computed tomography (ILUMA, Orthocad, CBCT, 3M Imtec, Oklahoma, USA), and the obtained sections were transferred to the 3D-Doctor (Able Software Corp., MA, USA) software. Two models were created in the study. In the first model, zygomatic and dental implants were used, while in the second model, pterygoid and dental implants were used. A 150 N vertical force and a 100 N oblique force at a 30-degree buccolingual angle were applied. With finite element analysis assessed stress distribution in the implants and peri-implant bone tissue.

Results: When the obtained stress data were examined, under vertical forces, the maximum stress on the implants was higher in Model 1 (151.984 MPa) compared to Model 2 (151.773 MPa), but no significant difference was observed. The stress formed in the metal substructure was higher in Model 2 (422.042 MPa) compared to Model 1 (308.376 MPa). The maximum principal stress in the alveolar bone was greater in Model 2 (46.866 MPa) compared to Model 1 (15.719 MPa), and the minimum principal stress in the alveolar bone was also greater in Model 2 (80.360 MPa) compared to Model 1 (76.310 MPa). Under oblique forces, the average stress on the implants was higher in Model 2 (128.297 MPa) than in Model 1 (79.607 MPa).

Conclusions: When the stresses occurring on zygomatic and pterygoid implants and the alveolar bone surrounding these implants were compared, it was observed that the use of zygomatic implants was more beneficial in reducing both dental and biomechanical stress.