Orthodontic pain causes pain and discomfort due to various factors like pressure, ischemia, inflammation, and edema concerned with tooth movement. This randomized clinical trial highlighted that laser irradiation used to ease the pain was only useful when utilised immediately after treatment. 

Compare the impact of single low-level laser therapy (LLLT) irradiation on pain perception among subjects having fixed appliance therapy. 

A total of 62 participants were selected and allocated to four groups. Patients of first and second group received laser and placebo on the right side, respectively and patients of group three and four obtained laser and placebo on the left side, respectively. The laser or placebo was implemented prior to separation, one and two days following the separation of their primitive permanent molars in the lower arch. The average of the pain noticed for the laser group noticed to be 1.1, which is lowered than the placebo group (1.6), just after the separation.

The groups exhibited no difference in the registered values following one day and prior to the new irradiation. In case of gender, only following the first irradiation in the placebo group, the male showed a significantly higher level of pain than female, and after two days, the laser group showed difference among the gender with a value of higher pain for women than for men.

The laser irradiation shows efficacy only if implemented quickly after treatment and separation. Except after the first placebo group irradiation, no difference was seen between the groups regarding genders. Both groups exhibited pain cycle peak at one day.