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.