Introduction: The aim of this study was to evaluate the wear of ProTaper Next rotary files, X1, X2, and X3 after shaping 6, 10, and 14 maxillary molar vestibular canals. Materials and Methods: One hundred and sixty-Two rotary files were divided into three groups according to the number of prepared canals, namely Group 1 (6 canals), Group 2 (10 canals), and Group 3 (14 canals). After canal preparation, files were embedded in resin molds, sectioned at 6 mm from the tip, and the wearied surface was microscopically evaluated. AutoCAD® software was used to measure the wear of edges in the different sections and multilevel mixed linear regression model to statistically analyze the data. Results: The files exhibited progressive wear as the number of uses increased. X2 and X3 files of Group 2 (10 canals) showed the highest wear, which decrease at 14 canals. Conclusions: X1, X2, and X3 files can shape until 10 canals without loss of their edge effectiveness.