Root canal shaping is a critical step in endodontic therapy. Peroperative errors such as: false canal, stripping…, may occur during this step.

Endodontic instrumentation based on stainless steel is often the cause of these errors because of the alloy rigidity of which it is made. To alleviate this problem, endodontic NiTi instrumentation was designed and then used to allow a better respect of the canal trajectory, thanks to the flexibility of the NiTi alloy.

One Shape® (Micro Méga, Besancon, France), is a NiTi root canal shaping system, a single file used in continuous rotation.

The aim of the present paper is to highlight the aspects of rotary mono-instrumentation and its additions to the root canal shaping.