Hi Rabbi, my wife has INVISALIGN Braces which can be taken off & she does take them off whenever she eats etc…but there is also cement applied to her teeth which does not come off. Does this cement present a problem of chatzitza?
If the cement attachments are permanent, i.e. they stay on for the duration of the treatment, usually about 2 years, they would have the status of traditional permanent braces which do not present a problem of chatzitza.
SHu”t Minchas Yitzchak 6:86, Shevet Halevi 2:98. cf. Igros Moshe Y:D 1:96.