Profound pulpal anesthesia is critical and is essential to prevent pain during endodontic treatment of diseased teeth with vital pulps. Inferior alveolar nerve block (IANB) is the most commonly used anesthetic technique for endodontic procedures in mandibular molars. Various reasons could be attributed to the failure of IANB in achieving profound pulpal anesthesia. Intraligamentary anesthetic technique has been proved to be an effective alternative to counteract this problem. Studies have shown that articaine, a long-acting amide anesthetic has better bone absorption when used as an intraligamentary injection. Similarly a short-acting local anesthetic, mepivacaine is known to produce effective pulpal anesthesia, but its efficacy, when used as an intraligamentary injection in achieving pulpal anesthesia, is not yet explored. Hence the aim of this study is to compare the efficacy of mepivacaine and articaine when used as an intraligamentary injection in achieving pulpal anesthesia of mandibular molars. Study design: 40 patients requiring root canal treatment of mandibular molars diagnosed with acute irreversible pulpitis will be selected. Patients will be randomly assigned to receive intraligamentary injections with either mepivacaine or articaine. Heft-Parker Visual Analogue Score (HP-VAS) will be used to assess pain before and after the procedure. Results: The study will be conducted and the results will be collected and statistically analysed. The primary outcome is to eliminate the pain immediately during the procedure and the secondary outcome is to observe the time taken for the anesthetic effect to wear off.