A Phase 4 interventional study of Articaine 4% with epinephrine 1:100,000 and Lidocaine 2% with Epinephrine 1:100,000 in Irreversible Pulpitis and Failed Inferior Alveolar Nerve Block, sponsored by Rehman Medical Institute - RMI. Completed at 1 site in Pakistan. Open to participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by Rehman Medical Institute - RMI · Phase 4, Interventional, and Treatment
Local anesthetic is used to numb a tooth before a root canal treatment. In lower back teeth with irreversible pulpitis (a painful, inflamed tooth nerve), the standard numbing injection near the jaw nerve, called an inferior alveolar nerve block, often does not numb the tooth enough. When this happens, patients may feel pain during treatment, and dentists often give an extra injection beside the tooth.
This study compares two numbing medicines used for that extra injection: 4% articaine and 2% lidocaine, both with epinephrine. Articaine is a newer medicine that may pass through bone more easily, but it is not clear whether it works better than lidocaine in this situation.
Adults aged 18 to 50 with a painful lower first molar needing a root canal first receive the standard nerve block with lidocaine. Patients who still feel pain when the dentist begins opening the tooth then receive an extra injection beside the tooth, with either articaine or lidocaine. Which medicine is given is decided by chance, and neither the patient nor the dentist knows which one it is.
Background: Inferior alveolar nerve block (IANB) with lidocaine is the standard anesthetic technique for mandibular molars, but it frequently fails in teeth with symptomatic irreversible pulpitis because of inflammation, altered nerve excitability and anatomical variation. Supplemental buccal infiltration is commonly used after a failed block. Articaine has higher lipid solubility than lidocaine and may diffuse better through mandibular cortical bone, but evidence for its superiority as a supplemental infiltration is inconclusive.
Design: This is a prospective, randomized, double-blind, two-arm parallel clinical trial conducted in the Department of Endodontics. Patients are randomized using a computer-generated list, with allocation concealed in sequentially numbered, opaque, sealed envelopes opened by an independent assistant who takes no part in treatment or evaluation. The anesthetic cartridges are masked and coded by a second investigator who is not involved in the clinical procedures, so the operator and patient are blinded to the drug used.
Procedures: All participants receive an IANB with 1.8 mL of 2% lidocaine with 1:100,000 epinephrine. After 10 minutes, anesthesia is assessed with an electric pulp tester and a cold stimulus. Patients who report pain during access cavity preparation despite lip and tongue numbness are considered to have a failed IANB. They receive a buccal infiltration next to the mandibular first molar with 1.8 mL of either 4% articaine or 2% lidocaine, each with 1:100,000 epinephrine. Injections use a standard aspirating dental syringe with a 27-gauge long needle for the IANB and a 30-gauge short needle for the infiltration. Pain during the procedure is recorded with the Heft-Parker Visual Analog Scale. If a patient reports moderate or severe pain, intraligamentary or intrapulpal anesthesia is given and the case is recorded as a failure for the assigned drug.
Sample size: Assuming a 30% difference in success rates, 80% power and a 5% significance level, at least 25 patients per group were required. To allow for dropouts, 30 patients per group were planned.
Analysis: Data are analyzed in SPSS version 21. Success rates are compared with the chi-square or Fisher's exact test, and VAS scores with the Mann-Whitney U test. A p-value below 0.05 is considered significant.
Ethics: The protocol was approved by the Institutional Ethics Committee and follows the Declaration of Helsinki. Written informed consent is obtained from all participants.
Rehman Medical Institute - RMI is the lead sponsor of 21 studies on the registry; 9 are open to participants now.
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All participants first receive an inferior alveolar nerve block with 1.8 mL of 2% lidocaine with 1:100,000 epinephrine. Participants who report pain during access cavity preparation (failed block) receive a supplemental buccal infiltration next to the mandibular first molar with 1.8 mL of 4% articaine with 1:100,000 epinephrine, using a 30-gauge short needle. Anesthetic success is judged by whether access preparation and initial instrumentation can be completed without pain.
Drug: Articaine 4% with epinephrine 1:100,000
All participants first receive an inferior alveolar nerve block with 1.8 mL of 2% lidocaine with 1:100,000 epinephrine. Participants who report pain during access cavity preparation (failed block) receive a supplemental buccal infiltration next to the mandibular first molar with 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, using a 30-gauge short needle. Anesthetic success is judged by whether access preparation and initial instrumentation can be completed without pain.
Drug: Lidocaine 2% with Epinephrine 1:100,000
Drug page: Carticaine
Supplemental buccal infiltration of 1.8 mL of 4% articaine with 1:100,000 epinephrine, given next to the mandibular first molar with a standard aspirating dental syringe and a 30-gauge short needle. It is given only to participants who report pain during access cavity preparation after an inferior alveolar nerve block with 2% lidocaine.
Also known as: Articaine Hydrochloride, Articaine with Adrenaline
Drug page: Lidocaine
Supplemental buccal infiltration of 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, given next to the mandibular first molar with a standard aspirating dental syringe and a 30-gauge short needle. It is given only to participants who report pain during access cavity preparation after an inferior alveolar nerve block with 2% lidocaine.
Also known as: Lidocaine Hydrochloride, Lignocaine with Adrenaline
Success of Pulpal Anesthesia With Supplemental Buccal Infiltration
Proportion of participants in whom access cavity preparation and initial instrumentation were completed without pain after supplemental buccal infiltration. Success was defined as no reported pain and no need for additional anesthesia. Pain was assessed using the Heft-Parker Visual Analog Scale (0-170 mm), with higher scores indicating greater pain intensity.
Time frame: Immediately after initial instrumentation during the single treatment visit.
Pain Intensity During Access Cavity Preparation (Heft-Parker VAS)
Pain intensity reported by participants using the Heft-Parker Visual Analog Scale (HP-VAS) during access cavity preparation and initial instrumentation after supplemental infiltration, compared between the articaine and lidocaine groups. The HP-VAS ranges from 0 to 170 mm, with higher scores indicating greater pain intensity (worse outcome).
Time frame: Immediately after completion of access cavity preparation and initial instrumentation during the single treatment visit.
Plan to share: No
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Ran from Mar 2026 to primary completion in Aug 2026, 5 months.
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Studies of the drug tested here: Carticaine
Rehman Medical Institute - RMI