Stress distribution of implant‑retained overdenture with different attachment systems a finite element analysis

The aim of this paper is to analyze the force transmission and stress distribution of an implant-retained overdenture and to assess the influence of the over denture retention system in the implants, peri-implant bone, and the posterior regions of the residual alveolar ridge. Material and method: A CBCT scan of the edentulous mandible was used to create a model. The tests were conducted on two models of a mandibular edentulous jaw, on which two implants were positioned in the interforaminal space. Different retention systems (ball, locator) and an acrylic removable prosthesis were placed in each model. The models were tested under axial loads of 150N, unilaterally and bilaterally, at the level of the first molar. These models were analyzed by finite element software (SOFIFTIK software package) using Von Mises stress analysis. Results: The highest stress values were observed at the implant necks and abutments in both models. Regarding the peri-implant bone and the posterior regions of RAG, the highest stress values were observed in the model with a locator attachment. Conclusion: According to the results of this study, we can conclude that ball attachments provide a more homogeneous distribution of load forces compared to locator attachments.
Keywords: implants, overdenture, FEM (finite element method), biomechanics, attachments