Age 7 or 8 - Don't be Late!
Children should be looked at by an orthodontist at age 7 or 8, with or without a dentist referral. This a nice precaution to take, no different than getting a child's vision checked before he starts school.
This is not to say that most children should be treated with braces at an early age. After all, most children are developing normally. And whether or not people appreciate it, it is normal for the teeth to look irregular and untidy at ages 8 to 10.
However, some orthodontic problems have a negative influence on growth of the face and jaws, and some problems simply get worse as time passes. By age 12 or older these problems may be be difficult to manage well. Would we "wait and see" as a yonger child gained excessive weight, or started to develop poor posture or behaviour problems?. Probably not. It would seem appropriate in these cases to intervene earlier instead of later. The same idea applies to some orthodontic problems. That is why we may see the occasional 8 or 9 year old in braces.