If your child still sucks their thumb so the permanent teeth erupt, it can begin to cause the effect on the teeth. If the thumb is placed in the mouth for a long period of time, the thumb itself acts like a brace – pushing up front to the front and down front teeth back. When the thumb rests between the upper and lower teeth, it can also prevent the normal eruption of the anterior teeth, causing open bites and the front teeth do not meet. If the habit is stopped earlier, teeth can begin to return to their normal position when children experience their growth and development. Kids thumb sucking habit can be overcomed by buying thumb sucking device via https://www.amazon.com.au/Age-2-7-STOP-Thumb-Sucking/dp/B00VQU2DZS. 

How do you stop a thumb or suck a finger?

As parents, we often start with gifts or a little bribe for our children, but as we know this is not always successful. Often, the thumb is sucked into comfort, and whatever to 'solve' comfort will help stop that habit. First we have to start with the child – if he is determined to stop that habit, it will happen, but having habitual breakers will help in termination of the habit.

All breaker habits work by acting as a reminder – let your child know that 'thumb is in the mouth and to get it out'.