My daughter is six years old and has a brownish color discoloration right below two of her lower teeth. One of those teeth are lose and will be falling out shortly(its a baby tooth).The other baby tooth does not appear to be loose yet.The two teeth with the discolored gums are located right next to the two centered bottom teeth ( baby teeth fell out already and big teeth have grown in)one on each side of them. She has been to the dentist in the past year and had no cavities. We have recently moved to a different state so our regular dentist is unavailable. She does not complain that her lower gums hurt. What may be causing this brownish discoloration on the lower portion of the gums directly beneath two of her lower teeth?