The purpose of this study is to assess the effect of preoperative Diclofenac Potassium (50 mg Cataflam) on the anesthetic success of buccal infiltration with 4% articaine with epinephrine 1:200,000 in mandibular molars with symptomatic irreversible pulpitis.

This study aims to evaluate the effectiveness of preoperative administration of Diclofenac Potassium (50 mg Cataflam) compared to placebo, one hour before treatment, on the anesthetic success of buccal infiltration with 4% articaine with epinephrine 1:200,000 in mandibular molars with symptomatic irreversible pulpitis. Patients with moderate-to-severe pre-operative pain are selected. Full medical and dental history will be obtained from all patients treated during this study by the operator. Clinical diagnosis of symptomatic irreversible pulpitis is to be confirmed. The primary outcome is success of buccal infiltration using articaine.The secondary outcomes are pain on injection. Patients will be recruited from the outpatient clinic of Endodontics at the Faculty of Oral and Dental Medicine, Cairo University.

Inclusion Criteria:

• Patients with active pain (moderate-to-severe) in mandibular molars.
• Patients with prolonged response to cold testing and electric pulp tester.
• Patient with the ability to understand and use pain scales.
• Patient with vital coronal pulp tissue on access.
• Patient who accept to enroll to the study.

Exclusion Criteria:

• Patients' allergies or any other contraindication to diclofenac potassium or articaine.
• Pregnant and lactating females.
• Patients having pain medication in the last 6 hours.
• Patient has more than one symptomatic mandibular tooth in the same quadrant.
• Patients with periradicular pathosis and/or radiolucency other than widened periodontal ligaments.
• Patients with active peptic ulcer and gastrointestinal disorders.
• Patients with history of bleeding problems or anticoagulant use within the last month.