This prospective clinical comparative study will evaluate the surface wear of BioHPP (modified polyetheretherketone) clasps opposing either natural tooth abutments or zirconia full-coverage abutments in mandibular bilateral distal extension removable partial dentures. Ten participants will be randomly assigned to two equal groups. Surface topography changes of the clasp fitting surfaces will be assessed using scanning electron microscopy (SEM) at denture insertion, 6 months, and 12 months. The findings will help determine the influence of abutment material on the wear behavior of BioHPP clasps and provide evidence for selecting appropriate abutment materials in removable partial denture treatment.