The Effect of Low-level Laser Therapy to Reduce Pain Caused by Orthodontic Separators: A Randomized, Double-blind Place-bo-controlled, Split-mouth Study

Thirty-three (n=33) participants from the Department of Orthodontics and Pediatric Dentistry, University of Szeged will be randomly assigned into two groups. A randomly assigned, split-mouth design will be used to avoid inter-individual biologic variation between patients. First, it will be randomly determined whether the upper or lower jaw would be involved in the study; after choosing the jaw blindly, the actual dental arch in the mouth will further be divided vertically, into right and left halves (quadrants) in each patient. One half will be the experimental side (i.e. the test quadrant) and will receive laser therapy, while the other half will be the placebo side (i.e. placebo quadrant) which will receive no laser, only placebo therapy. In the experimental group, a low-level medical gallium-aluminum-arsenide (GaAlAs) diode laser device (wavelength 980 nm, power: 100mW, producing 6 J energy), with continuous wave will used on the 1st permanent molars in the test quadrants. Using the split mouth design, patients will receive only a single dose immediately after the placement of orthodontic separators. Specified points in each quadrant will be treated from mesial, central and distal directions on the mucosa both buccally and lingually/palatinally with 10-10 sec for each, altogether for 60 sec, producing 36 J energy per molar. During the placebo treatment session, a similar procedure to that of the laser treatment session will be carried out, but with no laser irradiation. Therefore, to control the patient's pain-related behavior, and to maintain the blinded protocol, the handpiece will also be held on the placebo treatment side without laser irradiation following a similar application protocol. Patients will be instructed to denote their pain sensation levels (which is expected to be the primary come measure of the study), according to the localization (upper/lower jaw; right/left side) and the given appointments following the treatments: at 0 hours (i.e. withi