Fracture analysis of skeletal removable partial dentures - equation with several unknowns

Aim: The aim of the study is to identify the causes of fractures of partially mobile skeletal prostheses, to determine the technological register or the design aspects of the prosthetic solution according to the particularity of the clinical case. Methods: A total of 56 fractured, partially removable skeletal prostheses were analyzed by AFM (Atomic Force Microscopy) between 2019 and 2023 to determine the structural changes in the fractured area compared to the other areas of the prosthesis. The surface images were obtained with a Solver PRO-M scanning probe microscope (NT-MDT), in AFM configuration. Results: According to the results in the literature by comparing the fatigue limit on different criteria it was revealed that the surface roughness was a significant factor in the material performance and with a high influence on the fatigue strength of the specimen. The surface roughness in the fracture zone, is much higher than the surfaces in the areas that resisted external stresses. Conclusions: Usually, the failure of a metal material in operation is due to a combination of factors, which are found in the technological register or may be generated by the particularities of the clinical case that have not been taken into account.