Background: Local anaesthesia is essential for pain control in paediatric dentistry. However, conventional lignocaine with adrenaline is acidic (pH- 3.5), which often causes burning on injection, delayed onset, and shorter duration of anaesthesia. Buffering lignocaine with sodium bicarbonate increases pH closer to physiological levels, potentially improving aesthetic performance.

Aim: To evaluate and compare the efficacy of 8.4% sodium bicarbonate–buffered lignocaine with conventional lignocaine in children aged 8–10 years undergoing bilateral mandibular molar extractions.

Materials and Methods: A prospective, randomized, split-mouth clinical trial was conducted on children indicated for bilateral mandibular molar extractions. On one side, conventional 2% lignocaine with 1:80,000 adrenaline was administered (control group), and on the contralateral side, freshly prepared sodium bicarbonate–buffered lignocaine (10:1 ratio) was used (study group). Pain on injection was assessed using Visual Analog Scale (VAS), onset of anaesthesia (in seconds) was recorded, and duration of anaesthesia (in minutes) was measured. Data were analysed using Mann–Whitney U test; p < 0.05 was considered statistically significant.

Results: Buffered lignocaine significantly reduced pain on injection (mean VAS 2.70 vs. 4.10; p < 0.001), demonstrated faster onset of anaesthesia (mean 89.64 seconds earlier; p < 0.001), and prolonged duration (mean 215.34 vs. 190.07 minutes; p < 0.001) compared with conventional lignocaine.