Cleaning and shaping: hand and rotary instrumentation
Conservative Dentistry and Endodontics · Dental (BDS)
Study notes
Why are flexible NiTi rotary files preferred in curved molar canals over stiff steel files? Stiff steel files straighten inside curved canals — cutting into the outer wall (ledging, perforation risk) and missing the inner curve. Nickel-titanium's superelasticity lets rotary files follow the canal's natural curvature, centering the preparation and preserving the root's strength. Students learn: match file flexibility to canal anatomy; force against curvature causes procedural errors.
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