Why is a growth plate examination done before orthodontic treatment?

It is done to judge how much jaw growth remains so the treatment can be timed correctly. Bone maturity is usually assessed with a wrist X-ray, because dentofacial orthopedic treatment that guides growth of the upper and lower jaw is most effective when it starts during active growth. Generally the key period for growth-modifying treatment is around ages 10 to 12 for girls and 12 to 14 for boys. However, if a skeletal malocclusion such as an underbite or a receding chin is suspected, we recommend a first orthodontic examination earlier, around age 7.