Efficacy of sodium bicarbonate buffered versus non-buffered lidocaine with epinephrine in inferior alveolar nerve block: A meta-analysis

INTRODUCTION: This systematic review evaluated the use of buffered versus non-buffered lidocaine to increase the efficacy of inferior alveolar nerve block (IANB). MATERIALS AND METHODS: Randomized, double-blinded studies from PubMed, Web of Science, Cochrane Library, Embase, and ProQuest were identified. Two of the authors assessed the studies for risk of bias. Outcomes included onset time, injection pain on a visual analog scale (VAS), percentage of painless injections, and anesthetic success rate of IANB. RESULTS: The search strategy yielded 19 references. Eleven could be included in meta-analyses. Risk of bias was unclear in ten and high in one study. Buffered lidocaine showed 48 seconds faster onset time (95% confidence interval [CI], −42.06 to −54.40; P < 0.001) and 5.0 units lower (on a scale 0–100) VAS injection pain (95% CI, −9.13 to −0.77; P=0.02) than non-buffered. No significant difference was found on percentage of people with painless injection (P = 0.059), nor success rate (P = 0.290). CONCLUSION: Buffered lidocaine significantly decreased onset time and injection pain (VAS) compared with non-buffered lidocaine in IANB. However due to statistical heterogeneity and low sample size, quality of the evidence was low to moderate, additional studies with larger numbers of participants and low risk of bias are needed to confirm these results.