Anaesthesia for mandibular premolars with symptomatic irreversible pulpitis - which nerve block is best?

Abstract

A commentary on: Sülek T, Dumani A, Küden C, Kussever H, Yoldas O. Anaesthetic effectiveness of mental/incisive nerve block versus inferior alveolar nerve block in mandibular first and second premolars with symptomatic irreversible pulpitis: a randomised clinical trial. J Endod 2025; https://doi.org/10.1016/j.joen.2025.01.016 .

Design: This study is a randomised, double-blinded, parallel-group clinical trial investigating the efficacy of Mental Nerve Block (MNB) and Inferior Alveolar Nerve Block (IANB) techniques for anaesthesia of mandibular Premolars with Symptomatic Irreversible Pulpitis (SIP). The aim of the clinical trial is to establish if one anaesthetic technique is superior in facilitating Endodontic treatment in Mandibular Premolar Teeth with SIP and to explore if a difference is observed when comparing anaesthesia of First and Second Premolars with use of MNB and IANB techniques. Patients were enroled as per strict inclusion and exclusion criteria, then attended for Endodontic treatment of a Mandibular Premolar Tooth with SIP. Local anaesthetic block technique was determined by random assignment to MNB or IANB. To ensure blinding of the operator with regards to the anaesthesia method, one clinician administered anaesthesia and placed dental dam, and a second clinician completed the procedure.

Case selection: In total, 120 patients with a diagnosis of SIP of a Mandibular Premolar Tooth were enroled in the clinical trial. Inclusion criteria required participants be aged 18 to 65 years old and ASA Class I/II. Clinical signs indicative of SIP were required, including: carious pulpal exposure, haemorrhage during cavity preparation and prolonged pain in response to and persisting after thermal stimuli. Participants were excluded from the trial if they experienced pain involving multiple teeth or if there was use of pharmacological agents, with the ability to influence pain perception, within 6 hours of treatment. Participants were excluded from the trial if there was radiographic evidence of Periapical pathology, symptoms indicative of Apical Periodontitis or lack of anaesthesia 15 minutes after IANB administration. The sample size was determined using G*Power software and 60 patients were allocated to each group: MNB and IANB respectively. The drug preparation administered in all cases was 1.8 ml Articaine 4% with 1:100,000 epinephrine hydrochloride and the aspirating technique was used.

Data analysis: Statistical analysis was completed using SPSS Statistics. Patients were verbally questioned prior to Endodontic treatment, with responses recorded on the Numerical Rating Scale (NRS). Pain scores were recorded relating to pre-operative assessments, cold tests, cavity preparation and pulp extirpation. Success rates for the MNB and IANB anaesthesia groups were explored using chi-squared and probability ratio tests. The Man-Whitney U test allowed for comparison of tooth type and gender. In this study, success was defined as patients completing treatment with no pain (NRS = 0) or mild pain (NRS < 3), without additional anaesthesia.

Results: 120 patients were included in the clinical trial, 52 male and 68 female. The number of Premolar teeth that received Endodontic treatment was 120, this was comprised of 54 First Premolars and 66 Second Premolars. 60 patients were randomly allocated to each group: MNB and IANB, for each group data showed similar distributions of patient age, gender and tooth type. All patients reported lip numbness and both anaesthesia techniques achieved a success rate of approximately 70%. The percentage of patients that experienced pain during cavity preparation or pulp extirpation was 30% for both groups. These patients required supplementary injections and were given intraligamentary anaesthesia, 50% experienced adequate pain relief as a result. The IANB technique achieved sufficient anaesthesia for 71.4% of First Premolars and 68.8% of Second Premolars, with no statistically significant difference (P > 0.05). The MNB technique achieved sufficient anaesthesia for 76.9% of First Premolars and 64.7% of Second Premolars, with a statistically significant difference (P < 0.05) recorded comparing the Premolar tooth types.

Conclusions: IANB and MNB techniques have comparable efficacy in achieving anaesthesia of First and Second Premolars with SIP. The anaesthesia efficacy achieved by the IANB technique was comparable for First and Second Premolars. It would be beneficial to use the MNB technique for anaesthesia of First Premolars, compared to Second Premolars, as a statistically significant difference was recorded, with higher success rates observed for anaesthesia of First Premolars by the MNB technique. Irrespective of Nerve Block technique and Premolar tooth type, it was identified that for 1 in 3 Premolars with SIP supplementary anaesthesia was required to ensure adequate anaesthesia and patient comfort.