DEFORMATION OF PEEK AND COCR U-SHAPED PALATAL MAJOR CONNECTORS IN DISTAL-EXTENSION REMOVABLE PARTIAL DENTURE: A FINITE ELEMENT ANALYSIS

Abstract

This study investigated the deformation of major connectors of maxillary bilateral distal-extension removable partial denture (RPD) constructed with cobalt-chromium (CoCr) alloy and polyetheretherketone (PEEK). A three-dimensional maxilla model of a Kennedy Class I was developed from a patient’s cone beam computed tomography (CBCT). Two RPDs featuring identical U-shaped palatal major connector designs were fabricated with computer-aided design (CAD) software (SolidWorks 2017; SolidWorks Corp). The CoCr RPD framework had a uniform thickness of 1 mm, while the PEEK RPD framework was thickened to 2 mm. A total bilateral occlusal load of 320 N was applied to the posterior artificial teeth. The deformation of each framework was analyzed along the vertical (Z-axis), anteroposterior (Y-axis), and buccolingual (X-axis) directions by ANSYS Workbench software (ANSYS Workbench 2020; ANSYS Inc.). The PEEK RPD framework exhibited greater overall deformation than the CoCr RPD framework under the same occlusal load. For both materials, the maximum deformation occurred in the vertical direction (Z-axis), where the PEEK framework displaced 0.0128 mm compared to 0.0082 mm for the CoCr framework. Anteroposterior (Y-axis) deformation was also greater for PEEK. The deformation in the buccolingual direction (X-axis) was nearly identical for both materials. To conclude, the lower Young's modulus of PEEK results in greater flexibility and vertical displacement, suggesting a higher potential for transmitting occlusal forces to the underlying residual ridge mucosa. Conversely, the rigid CoCr framework provided broader force distribution.