Background and Aim: One of the important characteristics of nickel-titanium (Ni-Ti) rotary files is their dentin removal ability. The purpose of this study was to compare One Shape and F6 SkyTaper files in terms of dentin removal from the mesiobuccal canals of extracted first mandibular molars.

Materials and Methods: In this experimental study, 24 mesiobuccal canals of extracted first mandibular molars were selected. After preparing an access cavity, the samples were divided into two groups (n=12). The samples were air-dried and incubated for 8 hours at 82°C for moisture removal. The initial weight of the specimens was then measured. The samples in group A were prepared using One Shape (#25/0.06) files while the samples in group B were prepared using F6 SkyTaper (#25/0.06) files at a speed of 400 revolutions per minute (rpm) and torque of 2.2 N/cm for 10 seconds. The samples were again rinsed, dried, and incubated to eliminate moisture. The weights of the teeth were measured after preparation to compare the dentin removal efficacy. The results were analyzed using paired t-test (P<0.05).

Results: The mean weight of the removed dentin was 0.053±0.019 g in the SkyTaper F6 group and 0.045±0.073 g in the One Shape group, which was 0.008 g or 15% less in the One Shape group, but the difference was not statistically significant (P=0.6).

Conclusion: The amount of the dentin removed from the root canals by the SkyTaper F6 rotary system was greater compared to the One Shape rotary system although the difference was not statistically significant.