Analgesic Effectiveness of Magnesium Sulfate as an Adjuvant to Local Anesthesia in Symptomatic Irreversible Pulpitis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The inferior alveolar nerve block (IANB) is the most commonly used method for inducing pulpal anesthesia in patients with symptomatic irreversible pulpitis (SIP). Magnesium sulfate has been reported to increase the anesthetic effectiveness for endodontic procedures. Whether the adjuvant use of magnesium sulfate with IANB is effective in SIP patients remains uncertain. We performed an electronic search on PubMed, Scopus, Web of Science (WOS), and Cochrane CENTRAL from inception to September 2025 for randomized controlled trials (RCTs) assessing the adjuvant use of magnesium sulfate with IANB and local anesthesia compared to IANB with local anesthesia alone in patients with SIP. The primary outcome of interest was the pain scores following one and two hours post-procedure, while the secondary outcome was the anesthetic success rates. Standardized mean difference (SMD) and risk ratio (RR) with their 95% confidence intervals (CIs) were calculated using a random effects model. All analyses were performed using STATA 19MP. Seven RCTs comprising 398 patients were included in the final analysis. The adjuvant use of magnesium sulfate was associated with significant reductions in post-procedure pain scores at one hour (SMD = -1.97, 95% CI: -3.18 to -0.77, p < 0.001; I2 = 92.98%), without a significant difference at two hours post-procedure (SMD = -0.47, 95% CI: -1 to 0.06, p = 0.08; I2 = 0.00%). In addition, it was associated with higher rates of anesthetic success compared to the control group (RR = 1.61, 95% CI: 1.06 to 2.44, p = 0.02; I2 = 0.00%). The adjuvant use of magnesium sulfate showed a significant reduction in pain scores only at one hour following the procedure, without a significant difference at two hours. Moreover, magnesium sulfate had higher anesthetic success rates compared to the IANB alone. Further long-term RCTs with standardized protocols are recommended to confirm the current findings.