At what age can a child get an anti-tounge thrust appliance?

6 years (usually) Most tongue thrust appliances hook onto the 6-yr molars, so this is about the earliest one could be done. There are different options here, so speak with either an orthodontist (recommended) or your dentist to discuss the best way to approach this.
Debatable. Such appliances are very uncomfortable, some have spikes and are painful to kids. They interfere with eating and sometimes language. Why do you not try a speech pathologist, many have experience with tongue thrusting.