Canal transportation / zipping in curved canals
What it is
Canal transportation = iatrogenic deviation of the prepared canal away from its original path due to asymmetric dentin removal, especially in curved canals (files tend to straighten toward their original shape). Zipping (classic) = apical transportation that creates an elliptical/teardrop-shaped apical foramen in a curved canal (often accompanied by an "elbow" coronal to it).
Why it happens
• No glide path before rotary shaping → higher risk of canal modifications (transportation/ledging/zipping) • Forcing stiff/large instruments in a curved canal; inadequate pre-curving and poor negotiation technique (apical "zipping" mechanism) • Inadequate access / coronal interferences → instruments deflect and straighten aggressively • Over-enlarging apically (large tapers/sizes too early) or not using a crown-down/step-down logic → more apical stress and straightening
The full clinical mistake entry includes
- How to avoid it — the prevention protocol
- The clinical tip experienced clinicians use
- The documented reference behind the mistake
More clinical mistakes
Dentalverse is an educational resource for dental students and dentists. This page is a study reference — it is not medical advice and does not replace clinical judgment. Always follow your institution's protocols and your supervisor's guidance.