The primary goal of root canal treatment is to eliminate and prevent re-infection of the root canal system anatomy. In necrotic teeth, microorganisms can colonize anatomical complexities, such as isthmuses, ramifications and dentinal tubules and this causes infection and abcesses that are partially the reason why a root canal is performed. Instrumentation (dental files) can reduce the bacterial load by approximately 80%. However, the microorganisms cannot be completely eliminated with dental files alone as the file are very small but not small enought to get into every crevice of the roots of the tooth. sometime, in order to try and achieve this or simply due to inexperience or a lack of skill or knowledge, dentists over-instrument the canals, which is below the standard of care and often leads to catastrophic nerve injury.
After the canals are obturated (or cleaned out) the endodontist (or the general dentist if the patient has not been referred out to a root canal specialist: for the rest of this article we will refer to the practitioner performing the root canal as the “dentist” as both general dentists and endodontists are dentists) places sodium hypochlorite (NaOCl) solution into the canals to clean and disinfect them. This is a strong solution which, due to its antimicrobial/antibiofilm activity, and organic tissue dissolution capacity is able to clean and disinfect the canals. It is placed into the canal by the dentist using a needle coupled to a syringe, a system known as conventional syringe irrigation (CSI). CSI has a rinsing effect, which is an important part of the irrigation process. Once again, due to inexperience, a lack of skill, or nelgigence, too much apical pressure by the dentist can lead to sodium hypochlorite extrusion outside of the tooth roots and, many times, into the dental nerve which lays just beyond the apex of the tooth being treated (if the tooth is a bottom molar).