Efficacy and safety of the topical application of 0.2% HA gel on recurrent oral ulcers and to compare its effects in patients with recurrent aphthous ulcers (RAU) and the oral ulcers of Behçet's disease The efficacy of topical 0.2% hyaluronic acid gel on recurrent oral ulcers comparison between recurrent aphthous ulcers and the oral ulcers of Behçet's disease.