Effect of Cryotherapeutic and Nanotherapeutic Sodium Hypochlorite on Post-Operative Endodontic Pain.

This randomized clinical trial aims to compare the effects of conventional, cryotherapeutic, and nanotherapeutic sodium hypochlorite solutions used as final root canal irrigants on postoperative pain and substance P levels. The study will include 45 patients aged 18-50 years with symptomatic irreversible pulpitis and symptomatic apical periodontitis affecting single-rooted mandibular premolars. Participants will be randomly assigned to three equal groups (15 patients per group). The first group will receive conventional 2.5% sodium hypochlorite at room temperature, the second group will receive cryotherapeutic 2.5% sodium hypochlorite at 2-5°C, and the third group will receive nanotherapeutic 2.5% sodium hypochlorite as the final irrigant. Postoperative pain will be assessed using a 0-10 pain scale at 12, 24, and 48 hours. Substance P levels will be measured in periapical fluid samples using an enzyme-linked immunosorbent assay (ELISA). The study aims to determine whether cryotherapeutic or nanotherapeutic sodium hypochlorite can reduce postoperative pain and substance P levels compared with conventional sodium hypochlorite.

Inclusion Criteria: * Male and female participants aged 18-50 years. * Participants willing to complete the entire study period and provide written informed consent after receiving a full explanation of the study. * Presence of a mandibular single-rooted premolar tooth with vital pulp. * Patients diagnosed with symptomatic irreversible pulpitis and symptomatic apical periodontitis, presenting with intermittent or continuous sharp pain persisting after removal of the stimulus and severe preoperative pain assessed using the Visual Analog Scale (VAS). Exclusion Criteria: * Vulnerable populations, including prisoners, pregnant women, and individuals with mental illness, as specified in the protocol. * Teeth with open apices. * Teeth previously treated endodontically. * Presence of sinus tracts. * Periodontal pockets greater than 3 mm associated with the affected tooth.