Apical over-instrumentation (loss of apical constriction)
What it is
Instrumenting (and often irrigating/obturating) beyond the intended apical endpoint, so the minor diameter/apical constriction is enlarged or disrupted and the preparation effectively extends toward/through the major foramen.
Why it happens
• Working length set too long (no EAL, unstable EAL readings, poor radiographic confirmation) • Pushing files apically (especially stiff SS files) in curved/narrow canals; forcing when resistance increases • No control of apical "tug-back" / gauging and enlarging apically too aggressively (large taper/size too early) • Anatomy factors: resorption, open apex, apical foramen not coincident with the radiographic apex (so "to the apex" on a radiograph can mean beyond the foramen)
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.