Rotary nickel-titanium (NiTi) endodontic instruments were coated with a nanometric flexible TiO₂ layer through dip-coating sol-gel. Control groups and coated samples of superelastic NiTi instruments model RaCe 25/0.06 (0.25 mm tip-diameter, 6% conicity) were comparatively investigated with respect to the cutting efficiency, fatigue life, and corrosion resistance. Results showed an improvement in cutting efficiency for the coated samples and a high resistance to corrosion in NaClO. The coated instruments showed a better performance in fatigue life after corrosion.