Pain-temperature relation in the application of local anaesthesia

One hundred and thirty-six patients attending for local anaesthetic procedures in the trigeminal area were assigned to four groups. Each group was injected with the anaesthetic solution at temperatures 10 degrees C, 18 degrees C, 37 degrees C and 42 degrees C, respectively. Measurement of pain during injection was made on a numeric scale. The results show a strong relationship between the temperature of the anaesthetic solution and the pain of the injection (p << 0.001). This demonstrates that warming the anaesthetic solution significantly reduces the pain felt by the patient during injection, especially at 42 degrees C.