Comparison of buffered and non‑buffered lidocaine: pH and pain perception

Abstract

Commonly used local anaesthetic (LA) solutions in the field of dentistry are acidic, and have been known to cause pain and a burning sensation. The present study aimed to determine the pH levels of commercially available LA solutions with and without adrenaline and 8.4% sodium bicarbonate‑buffered LA solution, and to evaluate the pain during the administration of buffered and non‑buffered LA solutions. For this purpose, 20 patients with deep dentinal carious lesions with pulpal involvement affecting the bilateral posterior teeth and requiring the administration of a local nerve block were randomly selected to receive buffered and non‑buffered LA agents on either side, respectively. The patients were instructed to score the pain perceived during LA administration with the aid of a visual analogue scale (VAS) score of 1‑10. All the data obtained were subjected to statistical analysis. The results revealed that the LA solution of 2% lignocaine with 1:80,000 adrenaline buffered with sodium bicarbonate had a mean (± SD) pH level of 6.92±0.34 and non‑buffered LA solution had a mean pH level of 3.49±0.26. As per the VAS, a greater level of pain was reported during the non‑buffered LA administration (3.15±1.27) compared to the buffered LA administration (1.40±0.68). Buffered local anaesthetics were more likely than non‑buffered solutions to achieve successful anaesthesia [95% confidence interval (CI), 1.09‑2.41; P<0.001]. On the whole, the present study demonstrates that a significant reduction in the pain perceived in patients during the administration of LA agents buffered with sodium bicarbonate when used during pulpal involvement.