Does anyone know why i have yellow inbetween my bottom 4 teeth?!

i always thought i just diddnt floss enough but honestly i floss every morning and every time at night!. I have a bracket behind those 4 teeth because when they took of my braces they said I would have to wear this, now I think I started getting the yellow inbetween when I got that but i'm not sure!.!.!.!. it is either a yellow stain between those 4 teeth or glue from the bracket because it deffintly wont leave and I looked at it from an angle and its totally on there and also i have that little white spot at the bottom of my two front teeth i mean it doesnt show that much but still! my main concern is the yellow on bottomWww@Answer-Health@Com

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