The purpose of this prospective randomized, double-blind, placebo-controlled study is to compare the efficiency of 2 different single doses of pre-operative oral prednisolone (20 & 40 mg) for the control of inter-appointment endodontic pain in patients diagnosed with symptomatic irreversible pulpitis. The tested null hypothesis is that there is no difference in pain relief between the two doses.

Seventy-two patients presented for treatment at Dental University Hospital will be selected. The inclusion criteria are systemically healthy patients (ASA classification I or II), with no contraindications to corticosteroids (osteoporosis, systemic fungal infections, poorly controlled insulin-dependent diabetes mellitus, ocular herpes simplex, primary glaucoma, allergy to corticosteroids, ulcerative colitis, a compromised immune status, and major psychosis). Patients under 18 years, pregnant or breast-feeding, took an analgesic agent within the last 6 hours, those with un-restorable teeth, teeth with periodontal disease will be excluded. Patients having mandibular molars with symptomatic irreversible pulpitis with normal periapical area and moderate-severe preoperative pain (i.e. ≥ 34 mm on a visual analog scale (VAS)) will be included.

Subjects will be randomly divided into 3 groups, namely placebo (control), 20 mg prednisolone and 40 mg prednisolone according to a computerized random numbers. Each participant will receive a single oral dose of either formulation (drug or placebo) 30 minutes before starting endodontic treatment. All medications will be placed in identical containers and will be coded; thus, both the operator and the patients will be blinded to the type of medication. Endodontic treatment will be performed and canals will be instrumented to a minimum of size 30, .04 taper following the standardized protocol. Postoperative pain will be assessed by using a visual analogue scale at 4, 12, 24 and 48 hours after initiation of therapy.

Inclusion Criteria:

• Systemically healthy patients (ASA classification I or II), with no contraindications to corticosteroids (osteoporosis, systemic fungal infections, poorly controlled insulin- dependent diabetes mellitus, ocular herpes simplex, primary glaucoma, allergy to corticosteroids, ulcerative colitis, a compromised immune status, and major psychosis).

Exclusion Criteria:

• Patients under 18 years, pregnant or breast-feeding, took an analgesic agent within the last 6 hours, those with un-restorable teeth, teeth with periodontal disease