Stress Evaluation of Implant-Abutment Connections Under Different Loading Conditions: A 3D Finite Element Study
This study evaluated the effects of axial and oblique occlusal loading on implant-supported partial dentures with different connection systems (external hexagon, internal hexagon, and Morse taper). Upon axial loading, all systems presented similar stress values. Stress values increased under oblique loading. Stress distribution changed for some of the internal connection structures. It can be concluded that oblique load increases stress on bone structures and prosthetic components. Internal connection system implants present more favorable stress distribution patterns than do external connection system implants.
Figure 1. Occlusal loading schemes. Single arrows illustrate only loading direction: (a) Axial loading. (b) Oblique loading. Figure 2. Cortical bone, von Mises stress (MPa). Maximum stress surrounding the implant. (a) Axial loading. (b) Oblique loading. Figure 3. Trabecular bone, von Mises stress (MPa). On AX models, maximum stress is located at the bottom of each implant, while on the OB models, maximum stress is located also at the surface of the trabecular bone. (a) Axial loading. (b) Oblique loading. Figure 4. Implants, von Mises stress (MPa). Maximum stress location changed from the implants' platform (AX models) to the implants' neck (OB model). (a) Axial loading. (b) Oblique loading.
Figure 5 . Abutments, von Mises stress (MPa). Maximum stress concentration changed from the contact area between the abutments and the framework to the contact area between the abutments and the implants. (a) Axial loading. (b) Oblique loading. Figure 6. Frameworks, von Mises stress (MPa). Stress distribution was similar for both loading conditions, with increased maximum stress value upon oblique loading. (a) Axial loading. (b) Oblique loading. Figure 7. Prosthetic screws, von Mises stress (MPa). Maximum stress around the screws' neck. (a) Axial loading. (b) Oblique loading.
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