The SC ST serves dental practices that perform root canal retreatment and need to remove existing fillings before preparing the canal again. SOCO names retreatment as the setting, with the clinician choosing each file and setting the motor from the listed figures.
SOCO describes the work in stages: removing existing fillings such as gutta-percha and sealer, re-establishing the root canal pathway, and then preparing, disinfecting, and refilling. The four sizes support the first stages, with tip diameters of 15, 20, 25, and 30 and tapers of 06, 07, 08, and 09.
The motor settings are easy to remember. All four sizes run at 350 to 375 rpm, and torque is 1.5 N.cm for size 1506 and 2.0 N.cm for the other three. SOCO recommends higher rotational speeds, and the listed range sits at the top of the system's figures.
Length forms part of the choice. Size 1506 and size 2508 are listed at 18 mm, size 2007 at 22 mm and size 3009 at 16 mm. SOCO says the initial instruments are shorter and stiffer, and that some files have cutting tips to penetrate hardened filling material.
Collars in grey, yellow, red and blue let the team sort the files at a glance. A dental assistant can lay out the tray by colour, and the clinician reads the size from the handle during treatment. Because the four sizes increase in both tip diameter and taper, the order from 1506 to 3009 is easy to follow, and the specification table lists speed and torque before the motor is set.