Analysis of stress generated by implant-supported prostheses with pontic and cantilever designs on different abutment types in the posterior mandible using the finite element stress analysis method

Aim: In implant-supported prostheses, which are commonly used in the treatment of tooth loss, variables such as the number of implants, their position, and the design of the superstructure directly affect the stress distribution within the system. In this study, different implant placements that can be applied in cases of three missing teeth in the posterior mandible, along with splinted, pontic, and cantilevered superstructure designs, were evaluated using the finite element stress analysis method with three different abutment types. Material and Method: In the study, 4.3 mm diameter and 10 mm length bone level Nobel Parallel™ Conical Connection implants were modeled according to catalog dimensions. The abutments have a gingival height of 2 mm and a total height of 5.5 mm. The cement layer between the superstructure and the abutment was modeled at 50 µm, and the teeth were created according to anatomical references. Splinted, pontic, and cantilevered superstructures were designed according to the implant placement, and all models were analyzed under vertical and oblique loads. Results: Stress distribution varied depending on abutment type, prosthesis design, and load direction. An increase in the number of implants reduced stress levels, and pontic designs exhibited lower stress compared to cantilever designs. Stress increased significantly, particularly in distal cantilever models. The highest stress under vertical load was observed in prefabricated abutments, while under oblique load it was seen in custom abutments. Ti-base abutments produced moderate stress in both load directions. Stress distribution was found to be more homogeneous in splinted models. Principal stresses in cortical bone were higher than in trabecular bone, but all values remained within physiological limits. Conclusion: The highest stress was observed in the distal cantilever + custom abutment combination under oblique force, and this configuration was determined to be the most biomechanically risky option. Keywords: Dental abutment, cantilever, pontic, FEA, posterior mandible