The purpose of this prospective, randomized, double-blind, placebo-controlled study is to evaluate the effect of preoperative administration of alprazolam on the success of the IAN block for teeth with irreversible pulpitis.

Sixty patients diagnosed with irreversible pulpitis of a mandibular molar randomly receive, in a double-blind manner, identical capsules of either 0.50 mg alprazolam or placebo 45 minutes before the administration of a conventional IAN block. Access is begun 15 minutes after completion of the IAN block, and all patients profound lip numbness. Success is defined as no or mild pain based on visual analog scale recordings during access preparation and initial instrumentation.

Inclusion Criteria:

• patients with active pain in a mandibular molar
• prolonged response to cold testing with Endo-Frost cold spray
• Absence of any periapical radiolucency on radiographs
• a vital pulp while access cavity preparation
• ability to understand the use of pain scales.

Exclusion Criteria:

• patients were having allergy and sensitivity to benzodiazepines
• pregnant and breast feeding patients
• patients who had taken sedation within 24 hours before the treatment
• having pain in more than one mandibular tooth
• unable to give informed consent