Children find comfort from sucking a thumb, finger or a pacifier. This is normal. However, if the infant or child is doing this often, it can cause misaligned teeth and an irregular bite pattern.
Thumb sucking engages powerful muscles that can alter the shape of the palate. This, in turn, can affect the position of the teeth and lips. If the child continues to suck their thumb or fingers after the four anterior teeth have erupted, conditions can worsen and it may require surgery to be corrected.
It is recommended that if by 4 years of age a child is still sucking their thumb or fingers you should seek the advice of your dental professional.