IRCT2016061316582N2 IRCT 2016-10-31 Vice Chancellor for Research and Technology, Hamedan University of Medical Science comparison of analgesic drug and laser effect on pain reduction after orthodontic separator implementation Clinical comparison of Gelofen drug and low power diode laser effect on pain induced by orthodontic separator implementation 2016-03-19 anticipated 60 Complete https://irct.ir/trial/15494 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Supportive. N/A orthodontic pain. Intervention 1: In drug group patients receive 400mg Gelofen an hour before placing separator between the contacts of maxillary molars and after placement using laser facade flash without therapeutic effect . Intervention 2: In the laser group patients receive placebo of the Gelofen an hours before placement of separator between the contacts of maxillary molars.Immediately after separator placement laser will expose to three points of apex, mesial and distal. Laser properties include: Wavelength 940nm Exposure Time 20 seconde Exposure Dose 4j/cm2 Power 45 mw.