IRCT2014110414333N21 IRCT 2014-11-27 Vice Chancellor for Research Affairs, Kermanshah University of Medical Sciences Effect of laser treatment on CO2 oral lichen planus damage Effect of use and without use of laser treatment on CO2 oral lichen planus damage 2014-04-21 anticipated 50 Complete https://irct.ir/trial/13957 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment. N/A oral lichen planus. Intervention 1: The control group continued medication using local corticosteroid (Betamethasone pill .5 as daily mouthwash three times a day). Then control group is checked in 15 days, one, three and six month intervals and VAS damage size is measured by ruler scale and recorded accordingly. Intervention 2: The experiment group makes use of CO2 where first laser determines pain and burning rate using CO2 and VAS (measuring scale ruler), then start treating using laser at its highest power 2 watt and CO2 at the needed defocused distance away (1cm) reflecting on friction. Later hydrocoloride CO2 wash mouth Amen Benzyd laser is used for 5 days. Experiment group is checked in 15 days, one, three and six month intervals and pain rate and VAS damage size is measured by ruler scale and recorded accordingly.