I used to chew gum occasionally as a child, but when I got braces that was prohibited. My orthodontist even commented on the fact that he never had to reattach them due to gum chewing (which apparently a lot of his patients did even though they weren’t supposed to). I never went back to it after they came off.
Two things I remember were feeling ravenously hungry while chewing gum and also feeling bloated because I swallowed a lot of air, both of which were primary reasons for not going back to it.