Cleaning and shaping
Mechanical preparation creates space for disinfection without unnecessarily weakening the root. Irrigation reaches areas instruments cannot.
Understand
Shaping should preserve the original canal path while permitting irrigant exchange. Larger preparation is not automatically better if it thins a root or transports a curvature.
Assess
Estimate curvature and canal size, establish patency according to the chosen technique, and monitor file movement and debris. Sudden loss of length or resistance may signal a problem.
Apply
Use instruments within their design limits, irrigate and recapitulate as appropriate, and reassess if ledging, separation or perforation is suspected. Explain and document a complication promptly.
Key distinctions
Instrumentation removes infected dentine and creates a pathway for irrigants, but untouched recesses remain. A glide path and controlled sequence reduce procedural stress. File fatigue, excessive apical pressure and repeated reuse increase separation risk. The desired preparation respects the tooth's original anatomy and leaves enough root dentine for long-term survival.
Think through a case
A file binds in a curved canal and the measured length shortens. Stop and assess for blockage or ledge rather than forcing it apically.
The distinction to remember
Do not chase a large taper at the expense of the original canal path and root dentine.
Test your recall
Why avoid forcing instruments in a curved canal?
Show answer
It increases the risk of ledging, transportation or separation.