Is it forbidden to cap healthy front teeth if they protrude and have gaps that cause psychological distress?

Covering teeth after filing them, if for cosmetic purposes, is impermissible because it falls under altering Allah's creation. However, if it is for treatment or to remove a defect and restore the tooth to its natural state, then it is permissible. The general rule is that whatever is for beautification is forbidden, and whatever is for removing a defect is permissible.