Framework material and design influence on biomechanical behavior of removable partial dentures: A finite element comparison of polyetheretherketone and cobalt‐chromium

PURPOSE: This study evaluated the biomechanical impact of major connector designs and framework materials, polyetheretherketone (PEEK) and cobalt-chromium (CoCr), on deformation and mechanical stress distribution in the framework, periodontal ligament (PDL), and supporting mucosa through finite element analysis (FEA). MATERIALS AND METHODS: Intraoral data from a patient were obtained via cone beam computed tomography and a master model scan. Two removable partial denture (RPD) designs were modeled: a lingual plate and a lingual bar. A uniform pressure was applied bilaterally, producing a force of 120 N on each side. Deformation and stress distribution were analyzed using ANSYS Workbench FEA. RESULTS: For PEEK frameworks, the bar design reduced deformation in the framework and mucosa compared with the plate design but produced 25% higher PDL deformation. von Mises stress within the framework increased by 24% with the bar, while PDL stress increased by 58%, and mucosal stress decreased by 84%. In CoCr frameworks, the bar design similarly reduced framework and mucosal deformation, while PDL deformation showed minimal difference (9% lower with the plate). Unlike PEEK, the CoCr bar design reduced von Mises stress across all structures by 23%-57% compared with the plate. CONCLUSIONS: The optimal major connector design is material-specific. For PEEK RPD, a bar design may be considered for patients with metal sensitivity and strong abutment teeth. In contrast, a plate design may be indicated for cases with periodontally compromised abutments with good residual ridges. In CoCr RPD, the bar design offers superior stress distribution, whereas the plate may be reserved for cases with strong abutments and good ridge support.