Dimensional accuracy and stability of definitive dental models are critical factors in prosthetic rehabilitation, particularly in partially edentulous patients, where accurate reproduction of the peripheral seal directly influences the adaptation and stability of removable prostheses. The aim of the present study was to compare, under an in vitro experimental design, the dimensional stability of models obtained using different intraoral scanning systems in Kennedy Class I and III partially edentulous arches. Reference models were used as the gold standard and were scanned using the 3Shape TRIOS, MEDIT i700, and Shining 3D systems, evaluating linear, surface, and volumetric geometric variables.