Low intensity laser for reducing pain from anesthetic palatal injection

The aim of this study was to evaluate the effectiveness of pain reduction techniques for palatal injection, namely, low intensity laser therapy (LILT), topical anesthesia, pressure, and light touch.

Previous evidence indicates that LILT may prevent pain from palatal injection. However, no clinical trials evaluating this clinical question have been performed.

A double-blind clinical trial was conducted using 80 healthy volunteers, 18-25 years of age. The subjects were randomly allocated into four groups with 10 females and 10 males each group. Pain reduction techniques were administered at an injection point that was 10 mm from the margin of the palatal gingiva of the upper left first molar according to the following groups: (1) a 790 nm 30 mW continuous wave with a 0.13 cm2 focal spot at an applied energy of 3.6 J and fluence of 27.69 J/cm2, (2) 20% benzocaine, (3) pressure, and (4) light touch as the control. Then, 2% lidocaine with 1:100,000 epinephrine was injected using a 27-gauge needle with a pressure and volume control intraligamentary syringe. All subjects recorded pain on a 10 cm visual analog scale (VAS).

The pain score in the LILT group was <50 mm. The median of pain scores of the LILT, 20% benzocaine, pressure, and light touch groups were 11, 23, 27, and 31 mm, respectively. There was no statistically significant difference in VAS among the groups, using Kruskal-Wallis test (p=0.385).

No statistically significant differences in pain scores were noted among low intensity laser, 20% benzocaine, pressure, and light touch.