Mechanical stress and strain as determinants of fixed partial denture failure: A review of biomechanical factors and long-term prosthesis survival

Objectives: To analyze biomechanical factors influencing failure of fixed partial dentures (FPDs), focusing on stress distribution, strain behavior, and material fatigue. Methods: A structured literature review was conducted including in vitro studies, finite element analyses, and clinical investigations evaluating connector design, span length, occlusal loading, material properties, and prosthesis longevity. Results: High stress concentrations were frequently observed in connector and marginal regions, particularly under non-axial loading. Long-span prostheses demonstrated increased flexural stress and fatigue-related failures. CAD/CAM fabrication techniques and monolithic zirconia materials showed improved stress distribution and fracture resistance. Conclusions: Biomechanical planning plays a critical role in the long-term success of FPDs. Optimizing prosthesis design, material selection, and occlusal load distribution significantly reduces mechanical failure risk.