Starting early can improve your child’s chances of obtaining a perfect bite.
Early treatment (treatment started before all permanent teeth erupt), can often be more effective than later treatment. This can sometimes be the best way to completely correct a dento-facial problem.
It can sometimes be harder to obtain a full correction if treatment starts after the full eruption of permanent teeth. Early treatment (Phase I treatment) can take advantage of a child’s growing bones and muscles to correct and stabilize bites optimally. Phase I treatment can include gently widening a small jaw to fit in crowded teeth, using a habit corrector to avoid abnormal development, and other appliances that can guide jaws and muscles to create a perfect bite. Starting treatment early can often minimize and often fully correct jaw misalignment problems, and reduce time in full braces, when added in Phase II (after full permanent teeth erupt).
The final straightening, bite correction, and establishment of the best smile with use of full braces is reserved for Phase II. This usually takes place at approximately age 11 in girls, age 13 in boys, but of course this timing is very individual.
The American Dental Association (ADA) recommends children to have an orthodontic evaluation by 7 years old. The dentist can take records to see if there are potential problems for your child’s future that are unseen without machines and records. If needed, your dentist, will list the treatment goals of Phases I and II at the consultations, using computerized prediction methods to make the most accurate diagnosis.from http://www.individualortho.com/when-is-the-best-time/children/