Laser therapy is increasingly showing promising results in dental field including oral ulcers.This trial will assess the usefulness of Diode Laser compared to corticosteroid on oral ulcers of patients diagnosed with Behcet's disease.

The enrolled patients will be divided randomly into two groups.one group will receive Diode Laser (power:100 milli Watt,wavelength:980 mmm, delivery system:biostimulation probe) and other group will receive topical corticosteroids(Kenacort A Orabase: triamcinolone acetonide 0.1% 5 gram adhesive paste - Dermaphor) four times daily.

Inclusion Criteria:

• patients diagnosed with Behcet's Disease according to International Criteria for BD.
• patients with active oral ulcers.
• patients free from any visible oral lesions other than the oral ulcers of BD.
• patients who agreed to take the supplied interventions.
• patients who will agree to participate in the study.
• patients who will accept to sign the informed consent.

Exclusion Criteria:

• patients not physically able to participate in survey or clinical oral examination.
• patients with organ or life-threatening disease.
• patients with history of a severe or chronic medical condition including tuberculosis, hepatitis and human immunodeficiency virus.
• patients under immunosuppressive drugs.
• patients with organ transplantation.

Double - blinded trial:

Outcome assessor (CS) and Statistician. Participants couldn't be blinded because of the difference in the nature of interventions method of application.