The key to successful elimination of thumbsucking is motivation. The child and the parents must understand why the sucking must be stopped and the damage it causes to the teeth and palate. In some instances, a parent believes the child needs to suck, and that eliminating thumbsucking will rob the child of a necessary psychological satisfaction or will cause other aberrant behaviors to emerge. This is simply not true. In other instances, a child may have tried numerous gimmicks unsuccessfully or has been nagged relentlessly to get your thumb out of your mouth. 'The most important goal in presenting a thumb program is to convince both parent and child that you have a method which really works.
Pierce, R. B. (1994). Program to eliminate thumb (or finger) sucking, International Journal of Orofacial Myology, 20 (1), 52-53.