Dental implant fracture is closely connected to the stress buildup surrounding the implant system during static loading. In areas where the cross-section of the implant rapidly changes or where the geometry of the implant system has discontinuities, stress concentrations arise. Therefore, the implant’s design is crucial in preventing early failure of the implant system, including fracture, screw loosening, and increased leakage, in addition to reducing stresses at the implant–abutment interface. In the current work, three-dimensional (3D) models of mechanically connected Ti6-Al-4V implant systems in various dimensions were constructed. Finite element analysis (FEA) was used to conduct a stress study of the created implants under actual acting force static loading conditions in accordance with ISO 14801. In the created models, design elements including implant screw type, thickness, and taper angle of abutment were modified in order to increase the longevity of the implants. The results show that the equivalent stress level was dramatically reduced from 596.22 MPa to 212.72 MPa in the implant model, which exhibits a more homogeneous stress pattern under static loading conditions. By increasing the implant wall thickness from 0.15 mm to 0.40 mm in the region adjacent to the abutment, the stress levels, especially at the internal screw, were significantly reduced. Also, the design modification in Model B, establishing contact between the abutment and the upper part of the conical surface of the implant, resulted in a decrease in stress in the internal screw. Thus, enhanced homogeneity in stress distribution not only improves the harmony between the implant and surrounding tissues, thus increasing patient comfort and reducing the risk of complications, but also holds promise for the development of new implants capable of withstanding the forces encountered in the oral environment due to the relatively smoother stress transmission observed in this model.

Dental implant fracture is closely connected to the stress buildup surrounding the implant system during static loading. In areas where the cross section of the implant rapidly changes or where the geometry of the implant system has discontinuities, stress concentrations arise. Therefore, the implant's design is crucial in preventing early failure of the implant system, including fracture, screw loosening, and increased leakage, in addition to reducing stresses at the implant-abutment interface. In the current work, three-dimensional (3D) models of mechanically connected Ti6Al4V implant systems in various dimensions were constructed. Finite Element Analysis (FEA) was used to conduct a stress study of the created implants under actual acting forces static loading conditions in accordance with ISO 14801. In the created models, design elements including implant screw type, thickness, and taper angle of abutment were modified in order to increase the longevity of the implants. The results show that the equivalent stress level is dramatically reduced from 596.22 MPa to 212.72 MPa in the implant model, which exhibit more homogeneous stress pattern under static loading conditions. Furthermore, the relatively smoother stress transmission observed in this model holds promise for the development of new implants capable of withstanding the forces encountered in the oral environment.

Background and Objectives: In this study, uncoupled auxiliary trans-sacroiliac (UATS) screws were evaluated as a mechanically independent adjunct to conventional S2-alar-iliac (S2AI) fixation in long lumbopelvic constructs. We assessed their exploratory biomechanical behavior and preliminary clinical feasibility. Methods: Conventional bilateral S2AI fixation and the same construct supplemented with bilateral UATS screws were compared in an exploratory finite element analysis under flexion, extension, lateral bending, and axial rotation. A retrospective clinical series of 26 patients undergoing UATS-supported lumbopelvic reconstruction was also evaluated. Results: Across the four loading modes, the UATS configuration showed lower global implant-system stress (81–92% reduction) and lower global sacral stress (43–67% reduction) within the computational model. The clinical cohort was revision dominant (25/26 patients). Mean SIJ-related pain VAS decreased from 8.0 ± 1.5 to 2.4 ± 1.0 and ODI from 68.1% ± 18.1% to 16.7% ± 8.6% at final follow-up (both p < 0.001). These clinical changes reflect the overall reconstructive procedure and cannot be attributed independently to UATS fixation. Conclusions: UATS placement was technically feasible in this small, revision-dominant cohort and altered stress distribution in an exploratory, unvalidated finite element model. The present study does not establish independent clinical efficacy or superiority over established pelvic fixation or SIJ fusion strategies.