Finite Element Analysis of Trabecular-Surfaced Implants and Implant Angulation in Different Mandibular Arch Forms

Finite element analysis is commonly used to evaluate implant biomechanics, yet limited data exist on arch form and trabecular-surfaced implants. This study aimed to investigate the biomechanical impact of a designed trabecular surface compared with a standard implant surface in full-arch, four-implant-supported restorations, using two mandibular arch forms and four placement configurations. Finite element analyses were conducted under a 250-N oblique load applied at 30° to the posterior segment. The prosthesis was modeled as a titanium-acrylic hybrid structure. Stress distribution was evaluated in cortical and cancellous bones, implants, and prosthetic frameworks. Implants with a trabecular surface demonstrated lower stress concentrations in both bone and implant structures. The von Mises stress at the neck of the posterior implant decreased from 383.3 MPa (standard implant, hyperbolic arch, configuration 1) to 194.9 MPa (trabecular-surfaced implant, U-shaped arch, configuration 4). Similarly, the average maximum principal tensile stress in cortical bone reduced from 44.32 to 40.99 MPa with the trabecular design. Among placement strategies, Configuration 3 (all implants tilted distally) yielded the highest bone stress, whereas Configurations 2 and 4 provided more favorable load distribution. Stress concentrations were also higher in hyperbolic arches, whereas U-shaped arches exhibited a more uniform distribution. These findings emphasized the biomechanical advantage of the designed trabecular surface in reducing stress across bone and implant components, indicating that trabecular titanium may represent a more reliable and cost-effective alternative for clinical applications, potentially enhancing long-term stability. Independently, the arch form and placement strategy also significantly influenced load distribution. Despite assumptions such as isotropic, homogeneous, and linearly elastic material properties, and the use of a single oblique loading condition, this study offers valuable biomechanical insights such as the stress-reducing effect of the trabecular surface, the influence of three-dimensional arch anatomy on stress concentration sites, and the necessity of selecting implant configurations according to arch forms, which may inform future full-arch implant rehabilitations.