Effects of photobiomodulation with different application parameters on injection pain in children: a randomized clinical trial.

Photobiomodulation (PBM) has gained increasing interest due to its effectiveness in pain reduction in various fields of dentistry. However, the number of studies evaluating the effect of PBM on injection pain in children is very limited. The aim of the study was to evaluate the efficacy of PBM with three different application parameters (doses) + topical anesthesia on reducing injection pain and to compare these results with the placebo PBM + topical anesthesia in children during supraperiosteal anesthesia administration. 160 children were randomly divided into 4 groups, 3 experimental and 1 control, with 40 subjects in each. In the experimental groups, before the anesthesia administration, PBM with a power of 0.3 W was applied for 20, 30 and 40 s in groups 1, 2 and 3, respectively. In group 4, a placebo application of laser was performed. The pain felt during the injection was assessed using the Wong-Baker Faces Pain Rating Scale (PRS), and also the Face, Legs, Activity, Cry, Consolability (FLACC) Scale. Statistical analyses were performed to evaluate the data ( < 0.05). The mean FLACC Scale pain scores were 3.02 ± 2.93, 2.92 ± 2.54, 2.12 ± 1.89 and 1.77 ± 1.90 for the placebo group, and Groups 1, 2, and 3, respectively. Furthermore, the mean PRS scores were 1 ± 1.03, 0.95 ± 0.98, 0.80 ± 0.822 and 0.65 ± 0.921 for the placebo group, and Groups 1, 2 and 3, respectively. The "no pain response" rate was higher in Group 3 as compared to Groups 1, 2, and placebo according to the FLACC Scale and PRS; however, no difference was found between the groups ( = 0.109, = 0.317). Injection pain in children did not differ with placebo and PBM applied with a power of 0.3 W for 20, 30 and 40 s.