Single Sitting Root Canal Treatment (RCT). The naturally occurring space within the root of a tooth is called Root Canal. It consists of the pulp chamber, the main canal and detailed anatomical branches thIn the past, dentists always broke root canal therapy into two (or more) appointments. In the 1990's the single-appointment approach began to gain wide-spread acceptance, in part because advancements in technology made it possible to complete a patient's work in a single sitting without compromising treatment quality. Advantages. For the patient, the obvious benefit is that all of their treatment is completed in a single sitting. Although, with multi-rooted teeth that visit might be fairly extended, possibly as long as 90 minutes.at connect the root canals to each other or to the surface of the root.