IRCT201404149085N4 IRCT 2015-10-31 Vice chancellor for research and technology, Hamadan University of Medical Sciences Treatment of gum inflammation with laser Evaluation of photodynamic therapy with diode laser on reduction of gingival inflamation in fixed orthodontic patients -A randomized Clinical Trial 2015-10-12 anticipated 60 Complete https://irct.ir/trial/9705 interventional Randomization: Randomized, Blinding: Triple blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Other design features: Samples were randomly divided into three groups classified by gender. 4 Chronic gingivitis. Intervention 1: Intervention group 1: The use of diode laser for reducing gingival inflammation; Diode laser with the wave length of 940 nm and the power of 1.5 w is radiated using a fiber with the diameter of 300nm. the radiation pulse is 20 ms/s. 0.5 mm of the head of the instrument is located in gingival sulcus and radiated 3 times in 15 seconds through the buccal gingival sulcus. Intervention 2: Control group: The use of unpowered laser as placebo. Intervention 3: Intervention group 2: The use of diode laser with methylene blue for reducing gingival inflammation; One drop of 1% methylene blue solution is dropped in gingival sulcus and excess of the solution is washed off with water. Then diode laser with the wave length of 940 nm and the power of 1.5 w is radiated using a fiber with the diameter of 300nm. the radiation pulse is 20 ms/s. 0.5 mm of the head of the instrument is located in gingival sulcus and radiated 3 times in 15 seconds through the buccal gingival sulcus.