Efficacy of Combined Versus Supplementary Injection Techniques With Inferior Alveolar Nerve Block for Mandibular Molars With Symptomatic Irreversible Pulpitis: A Systematic Review and Network Meta-Analysis

Abstract

Background: Achieving effective anaesthesia in mandibular molars with symptomatic irreversible pulpitis is challenging. Various strategies involving the inferior alveolar nerve block (IANB) have been investigated, such as supplementing with additional injections after IANB failure (SUPP) or combining injections with IANB as primary injections (COMB). However, studies directly comparing SUPP and COMB are still lacking. Objectives: This study aims to assess and compare the anaesthetic effectiveness of different IANB strategies—SUPP and COMB—in mandibular posterior teeth with symptomatic irreversible pulpitis using a systematic review and network meta-analysis. Method: A comprehensive search was conducted in the PubMed, Embase, Cochrane Library, CINAHL and Scopus databases to identify relevant studies up to October 2024. Eligible randomised clinical trials (RCTs) were analysed using pairwise meta-analysis and network meta-analysis with a random-effects model to estimate treatment effects. Results were reported as risk ratios (RRs) with 95% confidence intervals (CIs) and surface under the cumulative ranking curve (SUCRA) values. The quality of the evidence was assessed using the CINeMA (Confidence in network meta-analysis) software (University of Bern, Bern, Switzerland). Results: A total of 28 studies involving five interventions were identified. Compared with IANB alone, both SUPP (RR = 2.02; 95% CI: 1.55–2.30; SUCRA: 85.1%) and COMB (RR = 1.86; 95% CI: 1.50–2.30; SUCRA: 64.9%) significantly improved anaesthetic success. However, there was no significant difference in effectiveness between SUPP and COMB. Conclusion: The quality of evidence ranging from low to high suggests that both SUPP and COMB are comparable in anaesthetic efficacy during endodontic treatment of mandibular molars with symptomatic irreversible pulpitis. However, both SUPP and COMB strategies showed significantly superior effectiveness compared to IANB alone.