Peri-implant mucositis is a reversible inflammatory condition primarily caused by biofilm accumulation around dental implants. Effective plaque control is essential for disease resolution; however, the influence of toothbrush bristle design on plaque removal around implant-supported prostheses remains unclear. Polybutylene terephthalate (PBT) tapered-end bristles are more flexible than conventional medium-textured bristles and may improve access to peri-implant areas while increasing patient comfort. This study aims to compare the effectiveness of a PBT tapered-end toothbrush and a medium-textured toothbrush in plaque removal, peri-implant bacterial load reduction, and patient-reported outcomes in individuals with peri-implant mucositis. Each participant will use both toothbrushes in a randomized sequence separated by a six-week washout period. Visible plaque will be disclosed and quantified using standardized photographic analysis based on the Rustogi Modified Navy Plaque Index. Absolute and relative peri-implant bacterial loads of Porphyromonas gingivalis and Fusobacterium nucleatum, together with total bacterial load, will be quantified by quantitative polymerase chain reaction. Patient satisfaction, including perceived discomfort, comfort, ease of handling and intention to use, will be assessed using visual analogue scales.