Effect of syringe size on severity of pain during local anesthesia administration

To know the pain intensity experienced by the patients using the two different syringes keeping the needle size constant.

The split-scalp, single-blind study was conducted in patients after obtaining informed consent. On half of side, 1-mL syringe with 30-G needle was used whereas on the other half, 3-mL syringe with 30-G needle was used. On each side, about 10 mL of anesthetic solution (1% Xylocaine with epinephrine in 1:100 000 dilution) at the room temperature was injected. After the injections, the patients were asked to rate the pain experienced by using the Wong-Baker Faces pain scale. The data were analyzed statistically using Mann-Whitney's U test.

A total of 20 patients included 16 male and 4 females. The mean age in the males was 31.6 years and 28.8 years in females. The mean pain scale with 1-mL syringe was 2.7 anteriorly and 2.45 posteriorly (P < 0.01), whereas the mean pain score with 3-mL syringe was 4.5 anteriorly and 4.25 posteriorly (P < 0.01). The mean pain score with anterior injections in males was 2.5 vs 3.5 in females (1-mL syringe) and 4.3 in males vs 5.5 in females (1-mL syringe). Similarly, the average pain score with posterior injections was 2.4 in males vs 2.8 in females (1-mL syringe) and 4.2 in males vs 4.5 in females (3-mL syringe), respectively (P < 0.01).

The pain intensity is affected by syringe size.