Aim: Comparing prevalence and severity of postoperative pain after usage of two different systems Reciproc reciprocating motion versus One shape continuous rotation for instrumentation root canals among symptomatic irreversible pulpitis patients.

Methodology: Fifty four patients, males - females, aged between 25-45 years, with non-contributory medical history, were incorporated into this trial who found eligible. In a single Visit root canal treatment, Vital mandibular premolars with single canals were treated with one of the aforementioned instrumentation systems. The eligible Participants were randomly subdivided into two groups (n=27); Reciproc and One Shape. Pain assessment was done using the NRS; Pre-operative pain was recorded, then patients were provided with instructions to report their pain scores at 6,12,24,48 and 72 hours postoperatively as well as the number of analgesics tablets " Ibuprofen 400 mg" taken on demand up to three days post-treatment.

Results: severity and prevalence of postoperative pain reveal no statistically significant difference at various follow-up periods (6,12,24,48 and 72 hours post-treatment) following single visit root canal treatment in patients with symptomatic irreversible pulpitis between both groups. Likewise, no significant difference was found concerning number analgesics administered in both groups .

Conclusion: The different motions used for root canal instrumentation have the same effect on postoperative pain as well as the number analgesics administered