Hi Dear, Welcome to HCM. Understanding your concern. As per your query you have recurring aphthous ulcer . There can be many reasons for recurring aphthous ulcer like stress ( very common) , trauma (like repeated trauma from any dental appliance ) or allergy to certain food like nuts and sea food or some medicines . There is also a possibility that aphthous ulcer reoccur due bowel disease . I would suggest you to to maintain proper oral hygiene by brushing your teeth twice a day , do chlorhexidine mouth wash rinses twice a day and do warm salt water rinses several times a day . Try to avoid food or drug if you think your are allergic to. If condition still persist or reoccur then consult oral pathologist for proper diagnosis and to rule out conditions like like stomatitis or bahcet s disease . Doctor may prescribe corticosteroid drug like dexamethesone or clobestasol , if they do not work effevtively the prenisolone will be the option. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari