Habits such as thumb-sucking or finger sucking can cause problems for the teeth, the bite and the jaws. It is important that oral habits are eliminated at an early age to minimize their potential damaging effects. There are various appliances that can be used to control and eliminate the habit. A thumb-guard is an appliance that fits over the thumb and makes it difficult or uncomfortable for the child to suck their thumb. A child with an oral habit should be seen by an orthodontist by the age of 5.