The Endodontics Errors in Root Canals Instrumentation

Errors
Damage could happen to teeth iatrogenically by dentist thought root canal cleaning
and shaping with conventional stainless steel instrument.
• Zipping: It results from tendency of instrument to straighten inside a curved root
canal. The main axis of the root canal is transported (internally or externally), so
that it deviates from its original axis. So, the terms straightening, deviation,
transportation are also used to describe this type of irregular defect. The terms
‘teardrop’, ‘hour-glass shape’ and ‘delta shape’ are also used to describe the
zipped apical part of the root canal.
• Elbow: It is associated with zipping and it occurs as irregular widening which
occurs coronally along the inner aspect and apically along the outer aspect of the
curve.
• Ledging: It happens as a platform on the outside of the curvature. It may occur as
a result of root canal preparation with inflexible instrument with sharp inflexible
cutting tip.
• Perforation: It may occur as a result of preparation with inflexible instrument with
sharp cutting tip. When used with rotational motion.
• Strip perforate: It results from over-preparation and straining along the inner
aspect of the root canal curvature.