I have looked at my 2.11 DD's back bottom molar and it has a quite large brown mark on the biting surface, which I am assuming is a cavity? I thought I'd been really careful with her teeth, she always brushes twice a day and although she does have some sweets and sugary treats they are treats, not a major part of her diet.
When she last saw the dentist, 6 months ago, he said she had soft enamel. I've made her an appointment for Monday morning.
I feel terrible, what have I done wrong?