My father has mouth ulcers for 7 months. Have consulted a gastroenterologist . He advised medicines for reflux acidity and gut (vsl 3) . Also his tissue transglutaminase test was weak positive. He is on gluten free diet. But after all medicines and diet control his mouth ulcers are not subsiding. He has been having mouth ulcers for last 25 years but every year they use to subside  itself but this time they have not subsided. Can you suggest what should be done ?