Black triangles

[parkersg]

hey everyone! how are you all?

so my bottom teeth were slightly crowded before starting invisalign, i'm 11 trays in now and they're straightening up great except for one thing

the problem is that inbetween my two lower middle incisors there now seems to be a black triangle (trinagle shaped gap) which is very unattractive looking

is this problem common and is there any way it can be fixed?

any help or advice on the matter would be greatly appreciated

thanks in advance!