This randomized controlled trial aims to compare the anesthetic efficacy of 2% lignocaine administered through an inferior alveolar nerve block (IANB) in one group of participants with 4% articaine delivered via primary buccal infiltration in other group in patients with symptomatic irreversible pulpitis in mandibular first molars.

This single-blinded randomized controlled trial evaluates the comparative anesthetic efficacy of two routinely used local anesthetic techniques for mandibular first molars diagnosed with symptomatic irreversible pulpitis. Inferior alveolar nerve block (IANB) using 2% lidocaine is a standard but technique-sensitive approach with reported failure rates of 20-25%, often influenced by anatomical variations and pulpal inflammation. Primary buccal infiltration with 4% articaine has emerged as a promising alternative due to superior bone penetration and favorable clinical outcomes in several studies, though evidence in adult South Asian populations remains limited.

A total of 330 systemically healthy adults (ASA I, aged 18-55 years) meeting strict diagnostic criteria for symptomatic irreversible pulpitis will be enrolled. Participants will be randomized into two groups:

• Group 1: 2% lidocaine (1:80,000 epinephrine) via IANB
• Group 2: 4% articaine (1:100,000 epinephrine) via primary buccal infiltration

All injections will be standardized to 1.8 mL delivered over 60 seconds using 27-gauge needles by a single experienced clinician. Topical anesthesia with benzocaine 20% will be used prior to injection. Dental anxiety will be screened using Corah's DAS, and patients with high or phobic anxiety scores will be excluded.

Fifteen minutes after administration, soft-tissue anesthesia will be confirmed (lip numbness for IANB and buccal probe response for infiltration). Pulpal anesthesia will be objectively assessed using an electric pulp tester (EPT) and subjectively using the Heft-Parker Visual Analogue Scale (VAS) at multiple treatment stages: baseline, post-injection, access preparation, pulp chamber entry, and root canal instrumentation.

Anesthetic success will be defined as:

• Two consecutive non-responsive EPT readings (max output 80)
• Mild or no pain during the procedure (VAS <55 mm)

Failure will be recorded if moderate/severe pain (VAS ≥55 mm) occurs at any stage or supplemental anesthesia is required.

The study aims to determine whether 4% articaine buccal infiltration can provide anesthetic efficacy equal to or superior to 2% lidocaine IANB for endodontic treatment of symptomatic mandibular first molars. The findings may help refine local anesthetic protocols and reduce the need for supplemental injections in challenging pulpal conditions.

Inclusion Criteria:

• Systemically healthy patients classified as ASA I, aged 18-55 years.
• Permanent mandibular first molar tooth requiring endodontic therapy.
• Diagnosed with symptomatic irreversible pulpitis without swelling or sinus.
• Normal periapical radiographic appearance (no evidence of periapical pathology).
• Moderate pain as assessed by the Heft-Parker VAS (>54 mm and <114 mm).
• Lingering pain or prolonged response to cold testing (lasting more than 10 seconds).
• Positive response to electric pulp testing.
• Outcome assessed must be pulpal anesthesia

Exclusion Criteria:

• • Pregnant or lactating mothers.

  • Teeth with reversible pulpitis, previously treated, or with calcified canals.
  • Teeth with severe periodontal disease or periapical radiolucency.
  • Patients who have taken analgesics or anti-inflammatory drugs within 6 hours before the treatment visit.
  • Patients on medications that could potentially interact with the anesthetic solution (e.g., antihypertensives, anticoagulants).
  • History of allergy to 4% articaine, lidocaine, or epinephrine.
  • Systemic diseases, immunocompromised states, or significant anxiety/mental health disorders.
  • History of vasovagal syncope on local anesthetic administration

IPD will not be shared because the study does not include plans or infrastructure for secure long term data storage, de-identification, and controlled access needed to protect participants privacy .Additionally, the data sheet is small and disclosure may include the risk of re-identification, summary results will be made available as required.

Participants will be blinded to the type of local anesthetic technique administered. They will not be informed whether they received an IANB with 2% Lignocaine or Buccal Infilteration with 4% Articaine. The operator and investigator can not be blindeddue to the nature of the procedure.