The aim of the study is to compare the anesthetic efficacy and need for supplemental anesthesia of 1.8 ml compared to 3.6 ml of 4% articaine buccal infiltration in mandibular molars with symptomatic irreversible pulpitis.

Patients with moderate-to-severe pain due to symptomatic irreversible pulpitis will be included. Patients will be randomly assigned into two groups to receive either 1.8 ml 4% articaine buccal infiltration or 3.6. ml 4% articaine buccal infiltration before single visit root canal treatments. Intraoperative pain will be assessed using an 11-point numerical rating scale (NRS) so that anesthetic success will be defined as no to mild intraoperative pain. The need for supplemental anesthesia will also be recorded.

Inclusion Criteria:

1. Healthy patients who are categorized as I or II according to The American Society of Anesthesiologists (ASA class I or II).
2. No sex predilection
3. Patients with symptomatic irreversible pulpitis
4. Patient with the ability to understand and use pain scales.
5. Patients who accept to enroll in the study.

Exclusion Criteria:

1. Patients' allergies to any of the drugs or materials used in the study.
2. Pregnant and lactating females.
3. Patients taking analgesics in the last 6-8 hours.
4. Patients having more than one symptomatic tooth in the same quadrant