will mouth ulcer causes bad breath?

A mouth ulcer (from Latin ulcus) is the name for the appearance of an open sore … Two common mouth ulcer types are aphthous ulcers (canker sores) and cold sores

It is the canker sores that causes the bad breath, since there is coagulated blood and salava mixture that creates a bacterial stench.

Im having bad breath, and I dont know why?

nowadays im having bad breathes, i dont now why
dont u think theses are the reasons?
~i have braces
~i got plenty mouth ulcers now
~im using an old toothbrush now

Ok get a new brush. Try a new toothpaste. And use mouthwash! I would recomend Winter Fresh becuase when i get an ulcer i use mouthwash and the minty kills them very fast. Oh and dont drink milk or citrus beucase that tends to make ulcers worse. Hope I helped! Good luck;]