The FDA listed and patented ThumbGuard™ appliance is designed with three things in mind:
1. Make it impossible for a child to suck its thumb or finger when the appliance is on;
2. Make it very difficult for a child to remove it;
3. Make it as unrestrictive and fun to wear as possible.
To suck his thumb, the child has to seal the thumb with lips to create suction. To prevent this from happening, the tubular part of the device which goes over the child’s thumb must be always larger in diameter than the thumb. When lips seal the tubular part on the outside, the gap (or space) between thumb and tube on the inside keeps the air flowing, thus breaking the seal.