The Effect of Anti-inflammatory Cryoagent on the Level of Postoperative Pain in Patients With Symptomatic Irreversible Pulpitis and Apical Periodontitis.

* The aim of this study is comparative between: 1. Intra-radicular cryotherapy using cold anti-inflammatory {ketorolac tromethamine at 2-5C}. 2. Intra-radicular final flush anti-inflammatory {ketorolac tromethamine at room temperature}. * In terms of: C. Level of post-operative pain {POP} using a visual analog scale {VAS}. D. Level of substance P in periapical fluid will be analyzed by enzyme-linked immunosorbent assay (ELISA) kit. Outcomes : * Primary outcomes: Level of Post-operative pain. * Secondary outcomes: Level of substance P expression