The Present Investigation Was Designed To Map The Mechanical Stress Propagation And Resulting Distortion In Maxillary Bilateral Distal-Extension Removable Partial Dentures (Rpds) Manufactured From Cobalt–Chromium (Cocr) And Polyetheretherketone (Peek), With Particular Scrutiny On The Abutment Tooth, Periodontal Ligament (Pdl), Mucosal Tissue, And The Structural Framework. Starting From The Subject’s Cone-Beam Computed Tomography (Cbct) Imagery And A Digitized Master Cast, A Three-Dimensional Maxillary Representation Was Produced, Featuring Six Anterior Maxillary Teeth. U-Shaped Palatal Major Connectors For Both The Cocr And Peek Rpd Variants Were Modeled Using Computer-Aided Design (Cad) In Solidworks 2017 (Solidworks Corp., Waltham, Ma, Usa). A Symmetrical Vertical Load Amounting To 320 N Was Delivered Onto The Bilateral Posterior Prosthetic Teeth. Three-Dimensional Finite Element Modeling Was Used To Determine Von Mises Stress (Vms) Fields Across The Abutment, Pdl, Mucosa, And Framework For Both Material Groups. In Contrast, The Framework’s Structural Deflection Was Quantified Using Ansys Workbench 2020 (Ansys Inc.). Stress Originated In The Free-End Saddle Region And Radiated Toward The Mucosal Surface, The Abutment, And The Pdl. Among Oral Anatomical Structures, The Highest Stress Magnitude Was Recorded At The Abutment, Declining Subsequently Through The Mucosa To The Pdl. The Vms Localized At The Abutment Under The Cocr Rpd Condition (9.098 Mpa) Proved Greater Than That Recorded For The Peek Rpd (7.515 Mpa). Yet, The Vms Values At The Mucosa And Pdl Were Broadly Equivalent Between The Two Material Systems. Divergent Stress Distribution Profiles Emerged Depending On The Framework Material. The Peak Vms Sustained By The Cocr Framework (107.99 Mpa) Was Substantially Superior To That Borne By The Peek Framework (11.7 Mpa). By Comparison, The Maximum Vertically Oriented Deflection Of The Peek Framework (0.0128 Mm) Exceeded The Corresponding Measurement For The Cocr Framework (0.0082 Mm). These Data Suggest A More Favorable Protective Capacity Of The Peek Rpd Toward The Abutment. Neither The Peek Nor The Cocr Rpd Appeared Predisposed To Cause Notable Mechanical Insult To The Mucosal Tissues Or The Pdl. Even So, The Cross-Sectional Bulk Of The Peek Framework Warrants Careful Consideration To Attenuate Stress Conveyance To The Residual Ridge Mucosa.
