[Pitfalls to avoid in the cleaning and shaping of the pulp canal]

Chemomechanical instrumentation of the root canal system is without doubt the most important but most challenging part of endodontic treatment. The first essential in cleaning and shaping is gaining direct access to the root canals. A properly prepared endodontic access opening can eliminate many of the technical problems encountered in root canal treatment. Excessive calcification in the root canal system and performing root canal treatment through existing artificial crowns however can be a challenge for the clinician. Secondly, enlargement of a curved root canal often results in loss of working length, incomplete removal or extrusion of the root canal content and unwanted alterations in the canal shape, such as transportation (stripping, zipping, elbow formation), ledge formation and perforation. This article focuses on the causes and effects of procedural errors during root canal cleaning and shaping. Each of these complications is addressed in a manner designed to prevent problems rather than to manage them once they are recognized. Throughout the immense amount of literature published the last 30 years on this topic, concensus is obtained concerning the preferential procedure of cleaning and shaping the root canal.