Instrumentation is a fundamental step in the success of endodontic treatment. For this success to be significant, there must be quality in the shaping procedure and no procedural errors such as deviations, zips, and instrument fractures, which may disadvantage the prognosis. Therefore, this research aimed to compare two manual systems to assess the quality of shaping and deviation in the respective thirds. Four groups with twenty-four simulated acrylic block canals were used: Group I – K-flexofile and Group II – ProDesign M.

The instrumentation of group I was performed using the biphasic technique recommended by São Leopoldo Mandic Institution, while in group II, instrumentation was performed according to the manufacturer’s protocol. Pre- and post-instrumentation photographs were taken for overlapping and sent for visual evaluation to three specialists and masters in Endodontics. After statistical analysis, the result was that there were no statistical differences between the groups in the middle and cervical thirds. However, there was a significant difference in the apical third, being that the K-Flexofile presented worse quality in canal shaping and a higher index of deviation. The results corroborate with findings in the literature where instruments manufactured from titanium nickel have characteristics superior to instruments manufactured from stainless steel, as they have a higher elasticity module, shape memory, and have a lower tendency to process errors.