IRCT201512076578N33 IRCT 2015-12-18 Vice Chancellor for research of Isfahan University of Medical Sciences The effect of admixture of clonidine and lidocaine as dental anesthesia solution on postoperative pain Evaluation the effect of admixture of clonidine and lidocaine in comparison with epinephrine and lidocaine on postoperative pain after single visit root canal therapy of mandibular molars with irreversible pulpitis 2015-12-22 anticipated 100 Other https://irct.ir/trial/7028 interventional Randomization: Not randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Prevention, Other design features: Five-digit random numbers are chose by using computer random number and are written on a label on the anesthetic solutions. And also each one will kept in a separate sealed opaque envelope. All these procedure is done by a third person who has no clue and has not involved in the rest of the study. Patients with simple random sampling protocol choose the envelope to determine which anesthetic solution will be administered. Only the random number is used on the data collection sheets to further blind the experiment. N/A Irreversible pulpitis. Intervention 1: Control group : 1.8 mL of 2% lidocaine with epinephrine 1:80000 (L+Epi) at a concentration of 12.5 μg/mL (Persicaine, Darupakhsh, Tehran, Iran) applied by using conventional inferior alveolar nerve block injection technique. Intervention 2: Intervention group: 1.8 mL of 2% lidocaine with clonidine (L+Clo) at a concentration of 15 μg/mL applied by using conventional inferior alveolar nerve block injection technique.