Evaluating low-level laser therapy effect on reducing orthodontic pain using two laser energy values: a split-mouth randomized placebo-controlled trial.

Background: No randomized controlled trial before has evaluated the role of low-level laser energy in its analgesic effects in orthodontics.

Objective: To evaluate the effect of single application of low-level laser with 4-Joule or 16-Joule energy on pain reduction following elastomeric separators placement.

Trial design: A two-arm parallel-group single-blind placebo-controlled randomized controlled trial, with implementation of split-mouth technique in each group.

Materials and methods: Twenty-six patients in need of orthodontic treatment with a fixed orthodontic appliance were enrolled and randomly allocated to either the 4-Joule or the 16-Joule laser energy group. Elastomeric separators were applied for the mandibular first molars. For each patient one molar received a single low-level laser dose using an 830-nm Ga-Al-As laser device with either 4-Joule or 16-Joule laser beam energy, while the other molar received a placebo treatment by applying the laser device in the same method and parameters as the counterpart molar without emitting the laser beam. The molar to be irradiated was also randomly chosen using simple randomization technique. Allocation was concealed and patients were blinded to which side would receive the laser irradiation. Main outcome measure was the degree of pain scored during mastication for each mandibular first molar after 1, 6, 12, 24, 48, and 72 hours of both laser and placebo treatments application. A questionnaire with an 100-mm Visual Analogue Scale (VAS) was used for pain assessment.

Results: Thirty-six patients were evaluated for eligibility, 10 of them were excluded making the final randomized number 26 patients. One patient dropped out later for not completing the questionnaire. Accordingly, the results of 25 patients were statistically analysed. No statistical significance was found for both low-level laser energy values in comparison to the corresponding placebo treatments. No harms were encountered.

Limitations: Intervention provider was not blinded to the intervention.

Conclusion: Low-level laser therapy, applied at two different laser energy values, is ineffective in relieving elastomeric separators induced orthodontic pain.

Trial registration: This trial was not registered.

Funding: No funding to be declared.