Canal-centering ability: An endodontic challenge.

During instrumentation of the root canal, it is important to develop a continuously tapered form and to maintain the original shape and position of the apical foramen. However, the presence of curvatures may cause difficulty in root canal instrumentation. The ability to keep the instruments centered is essential to provide a correct enlargement, without excessive weakening of the root structure. Several studies have shown that Ni-Ti instruments remain significantly more centered and demonstrated less canal transportation than stainless steel files. Considerable research has been undertaken to understand the several factors related to an instrument's canal-centering ability. In this article, we have discussed the influence of various parameters such as alloys used in the manufacture of instruments, instrument cross-section, taper, and have given tips on canal-centering ability.