The little girl has very poor appetite, we're on Gv, breastfeed every …

The little girl has very poor appetite, we're on Gv, breastfeed every 4 hours is great, as for complementary feeding it's not good, in a day she can eat one 100 gr fruit puree and that's all, the doctor said the upper gum is red, could the appetite disappear because of the teeth? If she ate porridge well, now a couple of spoons and refusal.