Patency in endodontics is the ability of a root canal instrument to freely pass through the entire canal without obstructions or blockages. Obtaining patency during root canal treatment is viable to be able to establish the working length that would reach the apical constriction of a root canal and thereby must be maintained during the entire cleaning and shaping, an obturation.
However difficulties in obtaining and maintaining it are common in the course of a root canal treatment due to many factors. Some of these factors are possible presence of radicular calcifications that could either be pathologic or physiologic, or could also be of istrogenic origin such as ledge and dentin mud formations.
Katrina N. Garcia-De Luna, DMD