Figure 2.

The median value of minimal (blue) and maximum (red) canal diameter in the mesiobuccal 1 root canal of the maxillary molar (data from table II). The corresponding diameters of the hand files with taper 0.2 and 0.6, and rotary files Protaper Universal and Next, iRace and Revo (data from table I). The selected file systems with various tapers seem to potentially leave unprepared root canal space depended in this type of root canal. The bars in yellow show the minimal diameter that is required for penetration of needles 27-g and 30-g during apical canal irrigation.