I think you need to go into more detail on what you mean by black dots in your mouth. Do you have more than one, like two or three? If it is what I had which was one, it could be what is called an almaglan(sp) tatoo. Definition, part of a filling came loose and settled in your mouth. This is harmless, however, you do need to have it removed and get it checked for pathology to insure that it is indeed an almagan tatoo. I had mine removed by a great ENT in Boston. I see that you live in Whitinsville, I live in Douglas.
