Evaluation of Postoperative Pain and the Antimicrobial Effect of Super Oxidized Water (Microcyn) and Chlorhexidine When Compared With Sodium Hypochlorite in Teeth With Asymptomatic Necrotic Pulps. A Randomized Clinical Trial (NRS)

Each canal will receive 2ml of super-oxidized water (Microcyn) irrigating solution between each instrument size and the subsequent one.

The difference in concentration of chlorine between NaOCl and super oxidized water such that the concentration of chlorine ions in NaOCl is much higher than that in super-oxidized water. However, considering the 90% reduction in biofilm thickness and 98% reduction in colony count of microorganisms by super-oxidized water as demonstrated

Each canal will receive 2ml of 2% chlorhexidine irrigating solution between each instrument size and the subsequent one.

Chlorhexidine (CHX) has been indicated as an alternative irrigation agent in the preparation of the root canal system, due to its broad-spectrum antimicrobial capacity, dentin tubule disinfection, dentin adsorption, high substantivity, and low toxicity compared to NaOCl. The inability to dissolve organic tissues of the CHX provides controversial in the use of this irrigant, and due to this limitation, some authors do not indicate it as the main irrigation solution in endodontic treatment despite its utility as a final irrigation solution.

Each canal will receive 2ml of 2.5 % sodium hypochlorite irrigating solution between each instrument size and the subsequent one.

Sodium hypochlorite (NaOCl) is the most common and has been widely used in endodontics for more than 70 years because of its ability to act as a solvent for organic matter and its efficient antimicrobial action, however, at high concentrations, it is likely to irritate periradicular tissues.

A pain chart using numerical rating scale (NRS) will then be used to record the patients' pain level.

The NRS (0-10 scale) consists of a line anchored by two extremes "No pain" and "the worst pain".

Patients will be asked to choose the mark that represented their level of pain from 0 to 10. Pain level will be assigned as follow: 0: no pain, 1-3: mild pain, 4-6: moderate pain, 7-10: severe pain.