Evaluation of biomechanical and thermal properties of zygomatic implants and subperiosteal implants in rehabilitation of atrophic total edentulous maxilla: A finite element analysis

Objective: In recent years, treatment options that allow for fixed prosthetic rehabilitation without the need for additional surgical procedures have gained popularity in cases with severely atrophic maxillae. Among these options are zygomatic implants and subperiosteal implants. The finite element analysis (FEA) method is not only an effective and predictable tool for simulating the mechanical behavior of biological tissues, but it also offers the advantages of creating models closely resembling actual anatomical structures and obtaining stress, deformation, and displacement data with high precision. The aim of this study is to determine the most appropriate surgical approach by evaluating the stress values occurring in the surrounding tissues, implants, and metal frameworks under masticatory forces and thermal stress using the finite element stress analysis method in an atrophic maxilla model involving zygomatic and subperiosteal implant designs. Materials and Methods: Two different models were developed in this study, utilizing zygomatic and subperiosteal implants. Group 1 consisted of four zygomatic implants placed in the regions corresponding to teeth numbers 14, 16, 24, and 26. Group 2 involved a two-piece subperiosteal implant design placed in the first and second regions. Vertical forces of 150 N and oblique forces of 100 N at a 30° angle were applied to the implant-supported prosthesis in the regions corresponding to teeth numbers 2, 4, and 6. While the stresses occurring in the maxillary alveolar bone were analyzed as maximum and minimum principal stresses, the stresses in the implants were evaluated in terms of Von Mises stress values (MPa, N/mm²). Thermal loading included a standard heat application simulating an oral cavity temperature of 60°C for a duration of 1 second. Following thermal loading, the temperatures at the cervical and apical implant–bone interfaces were measured in degrees Celsius. Results: The findings of the study revealed that Group 1, which included zygomatic implants, exhibited the highest levels of both maximum and minimum principal stresses. Assessment of stress distribution in the alveolar bone showed that the highest stress concentration occurred in Group 1. During thermal analysis, the highest temperature at the buccal interface region was recorded in Group 2, which included subperiosteal implants. At the apical region, the temperature values were found to be identical in both groups. Conclusion: Based on the results of this study, subperiosteal implant designs may be considered a highly predictable treatment option for performing fixed prosthetic rehabilitation in edentulous atrophic maxillae without requiring additional surgical procedures, as indicated by the stress distribution on both the alveolar bone and implant body. However, to obtain more definitive results, the study should be supported by further in vivo experimental and clinical research.