Variability of master gutta-percha cones.

The common technique to hermetically fill prepared root canals involves the use of "standardised" gutta-percha cones that are selected to fit the apical portion of the prepared canal space. These gutta-percha cones are manufactured to conform to a standard size and taper which should correspond to the size and taper of standard root canal instruments. Clinical observation of commercially available gutta-percha cones seemed to indicate that there is wide variation in the diameter and taper of "standardised" gutta-percha cones within the size range 25-35.