Occasionally, I will encounter extremely curved canals in my practice. These canals were treated with a lot of patience, perplexity and gentleness. Procedural errors like canal blockage and instrument separation are more likely to occur in these difficult canals. More flexible nickel-titanium files are recommended for shaping curved canals compared to stainless steel files which are more stiff, hence may lead to canal ledging and transportation. However, nickel titanium files are more prone to separation in very curved canals even in the hands of very experienced and skillful operator because of straining of the metal at the curvature. In other words, nickel-titanium files are useful in shaping curved canal but these are also easy to break.
