A number of methods may be used to reduce the discomfort of local anesthetic injections. These might include the application of topical anesthetics before needle penetration and a slow rate of injection. However, there is little evidence in the literature that the various methods proposed are reliable. Even the use of topical anesthetics before injection [...]

The pH of the plain lidocaine solution was 6.6; the epi-nephrine-containing solution’s pH was 4.4.
Twelve volunteers (6 men, 6 women) recorded at least one of their buccal injections at a minimum of 30 mm on the VAS, and 17 participants (10 men, 7 women) had palatal injection scores of at least 30 mm for one [...]

A batch of 2-mL 2% plain lidocaine and a pack of 2% lidocaine containing 1:80,000 epinephrine were supplied by the manufacturer (AstraZeneca, King’s Langley, Herts, UK). The cartridges were identical except for an individual label on each cartridge that contained an identifying code number. The pH of a sample of each solution from the same [...]

Anumber of factors may influence the discomfort of dental local anesthetic injections. Parameters independent of technique but relating to materials that might affect pain at delivery include the temperature and the pH of the local anesthetic solution. Buffering the solution can reduce injection discomfort. However, this is impractical when using prefilled dental local anesthetic cartridges. [...]