Assessment of Post-Operative Pain After Using Cryotherapy and Dexamethasone in Symptomatic Irreversible Pulpitis With Acute Apical Periodontitis: A Randomized Clinical Trial.

sixty patients with single root teeth diagnosed with symptomatic irreversible pulpitis with acute apical periodontitis will be treated in two visits with time interval 72 hrs. Later, they will be randomized into four groups according to the type of irrigant used, group (A): (cold NaOCl , dexamethasone) for 1st visit and cold saline as final rinse for 2nd visit, group (B): ( NaOCl, dexamethasone) for 1st visit and saline as final rinse for 2nd visit (room temperature), group (C): cold NaOCl and cold saline and group D: NaOCl and saline room temperature as control group. Each group will be prepared with trunatomy rotary files according to manufactures instruction. Inflammatory mediators IL-8 and substance P will be assessed by absorbent paper points after access preparation and before obturation using ELISA test. Post-operative pain will be measured after first visit at 6,12, 24,48,72 hrs. then after second visit at 12,24,48,72hrs and 7 days using the visual analogue scale.