Biomechanical Behavior of Endodontically Treated Abutment Teeth with Periapical Lesions: A 3D Finite Element Analysis.

Objectives: The stress distribution of teeth with periapical lesions, which are used as abutments in fixed prostheses, and its effect on the success of the restoration are not well known. This study investigates stress distribution in abutment teeth with periapical lesions and surrounding tissues under occlusal load using finite element analysis. Materials and Methods: Three models were constructed: (1) a healthy mandibular premolar, (2) a premolar with a periapical lesion restored using a fiber post and single crown, and (3) a similar premolar used as an abutment for a three-unit bridge. A static load of 300 N was applied at a 45-degree angle to the tooth's long axis, targeting the lingual slope of the buccal cusp. Stress and deformation were analyzed across all structural components, including dental tissues and the surrounding trabecular bone. Results: The results demonstrated that, in model 2, stress propagation extended more prominently along the root surface and progressed apically, resulting in a higher stress concentration in the periapical lesion region (0.061 MPa) when compared with model 3 (0.054 MPa). Furthermore, the greatest deformation was also observed in model 2. Across all models, peak stress was consistently localized in the cervicobuccal collar region of the tooth. Conclusion: These findings underline the importance of prosthesis design in reducing the stress concentration in abutment teeth with periapical lesions and demonstrate the biomechanical advantage of splinted restorations over single crowns in cases with periapical lesions.