RESUMEN
The study involved numerical FEA (finite element analysis) of dental implants. Based on this, fatigue tests were conducted according to the PN-EN 14801 standard required for the certification of dental products. Thanks to the research methodology developed by the authors, it was possible to conduct a thorough analysis of the impact of external and internal factors such as material, geometry, loading, and assembly of the dental system on the achieved value of fatigue strength limit in the examined object. For this purpose, FEM studies were based on identifying potential sites of fatigue crack initiation in reference to the results of the test conducted on a real model. The actions described in the study helped in the final evaluation of the dental system design process named by the manufacturer as INTEGRA OPTIMA 3.35. The objective of the research was to identify potential sites for fatigue crack initiation in a selected dental system built on the INTEGRA OPTIMA 3.35 set. The material used in the research was titanium grade 4. A map of reduced von Mises stresses was used to search for potential fatigue crack areas. The research [loading] was conducted on two mutually perpendicular planes positioned in such a way that the edge intersecting the planes coincided with the axis of the system. The research indicated that the connecting screw showed the least sensitivity (stress change) to the change in the loading plane, while the value of preload has a significant impact on the achieved fatigue strength of the system. In contrast, the endosteal implant (root) and the prosthetic connector showed the greatest sensitivity to the change in the loading plane. The method of mounting [securing] the endosteal implant using a holder, despite meeting the standards, may contribute to generating excessive stress concentration in the threaded part. Observation of the prosthetic connector in the Optima 3.35 system, cyclically loaded with a force of F ≈ 300 N in the area of the upper hexagonal peg, revealed a fatigue fracture. The observed change in stress peak in the dental connector for two different force application surfaces shows that the positioning of the dental system (setting of the socket in relation to the force action plane) is significantly decisive in estimating the limited fatigue strength.
RESUMEN
The MaI Implants® method offers a modern treatment option for specific patients who lack sufficient bone for traditional screw-based implants. The aim of the article is to use Finite Element Analysis (FEA) to examine the behavior of a subperiosteal implant under actual conditions within the oral cavity and to assess the impact of various mechanical factors on the durability of the MaI Implants®. A strength analysis was conducted using Finite Element Analysis for two models. The first was a single subperiosteal implant, while the second was a model of an arch consisting of two single subperiosteal implants connected by a bar. Based on the obtained results, it can be observed that the increase in load from 100 N to 800 N leads to an increase in displacements throughout the implant. Changing the angle from 90 to 30 degrees resulted in a 576% increase in the average displacement value across all multi-units. Stresses in the multi-units range from 23.7 MPa to 268.5 MPa. The lack of proper stabilization of the implant has the greatest impact on the results of displacements. Such displacements are significant for the later positioning of the implant compared to the initial conditions.