The analgesic effect of adding magnesium sulphate to inferior alveolar nerve block in mandibular third molar surgery: a randomised controlled trial.

Achieving a prolonged analgesic effect from an inferior alveolar nerve block (IANB) following mandibular third molar (MTM) surgery remains a challenge. This study aimed to investigate the analgesic efficacy of adding magnesium sulphate to an IANB on postoperative pain within 24 h following MTM surgery. The eligible participants were randomly assigned to receive articaine with either 150 mg or 250 mg magnesium sulphate, or articaine alone. The primary outcomes were pain intensity at 6 and 24 h postoperatively, using the Heft-Parker visual analogue scale (VAS). Secondary outcomes included the success rate of IANB, characteristics of analgesic consumption, and occurrence of adverse events. Multivariate analysis including multivariate linear regression was performed with a significance level of 0.05. A total of 72 MTMs were included. At 6 h postoperatively, the estimated treatment differences in pain at rest were -42.02 (95% CI: -61.50 to -22.54) for the 150 mg magnesium group, and -42.76 (95% CI: -62.42 to -23.11) for the 250 mg magnesium group. For pain on movement, the differences were -38.07 (95% CI: -60.22 to -15.92) and -29.07 (95% CI: -51.42 to -6.72), respectively. By 24 h, pain intensity did not differ significantly among the groups. First analgesic use was significantly delayed in both magnesium groups. The addition of 150 mg magnesium sulphate to articaine for IANB significantly reduced pain intensity at 6 h following surgery with no adverse events.