Abstract Restoration of root canal-treated teeth presenting with apical lesions requires careful selection of post-materials because their mechanical properties influence stress transfer within dental and supporting structures. This study aimed to evaluate, using finite element analysis, stress distribution patterns in a mandibular premolar with root canal treatment and an apical lesion restored with fiber, cast metal, or zirconia post systems supporting a three-unit bridge under occlusal loading. Four 3D finite element models were developed: a healthy premolar reference model and three lesioned premolar models restored with fiber, cast metal, or zirconia posts integrated into a three-unit fixed prosthesis. A static occlusal load of 300 N was applied at 45 degrees to the long axis of the tooth on the lingual incline of the buccal cusp. Deformation behavior and equivalent stress (von Mises) distributions were computed across dental tissues, prosthetic components, and surrounding bone structures. Occlusal loading generated consistent stress concentration patterns across models, predominantly in the buccal cervical region, the load-application cusp, and the cervical and middle thirds of the root, with intensified stresses at prosthetic connector regions. Posts with higher elastic moduli retained stresses within the post structure and reduced transmission to dentine, whereas fiber posts promoted more homogeneous stress distribution into surrounding dental tissues. These findings indicate that elastic compatibility influences load transfer pathways within structurally compromised abutment teeth. Within the limitations of this computational study, higher-modulus post systems localized stresses within the post, whereas lower-modulus fiber posts redistributed stresses to dentine, demonstrating that post-material selection significantly affects biomechanical response in lesioned teeth supporting fixed prostheses.
Kırmalı et al. (Wed,) studied this question.