First and foremost, remember that most children use sucking their thumb as a way to self-soothe and if possible, the coping mechanisms itself is what needs to be exchanged for something else. If the child has reached an age where they can comprehend why it has become a problem, simply explain to the child why it's a problem and try to reason with them.
Make them aware that it could make their teeth crooked and use that to help them realize it can have a negative effect. The ADA says that, generally, children who are just resting their fingers in their mouths out of habit will easily be broken of it, whereas children who are aggressively sucking may have a harder time with the idea to change. You can also buy best thumb guards from Nipit to prevent thumb sucking.
If your child constantly, here are some hints and tricks to try. Be sure to do this each time prior to the time of their normal habit of sucking their thumbs, as before nap and sleep.
- Putting a bandage on the thumb of their
- Put the thumb in a bad tasting vinegar or other substances
- If your child sucking their mothers when they are anxious, try to change the mechanism to help calm the anxiety in other ways
- Let your child help choose a method to help them quit (if old enough)
- Are you a dentist/hygiene helps to explain why they should stop (outside authority other than the mother or father)