The Effect of Implant Length and Bone Quality on the Biomechanical Responses of Dental Implant and Surrounding Bone – A Three-Dimensional Finite Element Analysis

The robustness of dental implant systems in the context of occlusal restoration relies significantly on biomechanical factors associated with the imposition of excessive loads. These factors encompass the macro geometries of the implants, bone qualities, parafunctional oral habits, and specific materials employed. The choice of different implant lengths in different bone qualities may give rise to distinct effects on the way loads are distributed across the interface between the implant and the adjacent bone. As of now, the influence of implant length and bone quality on the surrounding tissues and the stability of implant structure continues to be a matter of debate and uncertainty, particularly in situations involving the possibility of implant failure. This study employed three-dimensional finite element analysis to investigate five distinct implant lengths (4, 6, 10, 13, and 15 mm) in two types of bone quality (type II and III). The bone tissues were characterized through the utilization of computed tomography image datasets and then underwent processing within the SolidWorks software. All geometric configurations were transformed into finite element models, which were subjected to analysis within the ANSYS software. Anisotropic and isotropic properties were attributed to the bone and implant models, respectively. A dynamic occlusal loading quantified at 300 N was applied to the implant body, accompanied by a pre-tension force of 20 N on the screw component. The longer implants exhibited decreased stress magnitudes in type II bone (87.86 – 36.66 MPa) and increased stress magnitudes in type III bone (80.5 – 2128.9 MPa) within the surrounding bone tissue, in comparison to the shorter implants. However, stress within the implant body was generally elevated with the use of longer implants in both bone types (type II: 505.32 – 625.35 MPa; type III: 500.45 – 2186.7 MPa). Irrespective of bone quality, the longer implants predominantly led to lower bone strain levels (type II: 0.006828 – 0.003328; type III: 0.054250 – 0.021678) and overall deformation of the implant-abutment assembly (type II: 0.1458 – 0.1348 μm; type III: 0.1754 – 0.1492 μm) compared to their shorter counterparts. Among all the assessed findings, type III bone displayed a more pronounced adverse impact on the biomechanical responses of the dental implant and neighbouring bone except for the implant stresses under the applied physiological loading.