Tooth position and the relationship of upper and lower jaw is determined by many factors. No doubt there is a lot of genetics involved. The best way to predict if your kids teeth are going to come in straight or crooked is to look at the teeth of the biological parents. If mom or dad had braces as a kid or even surgery to properly align the teeth chances are pretty high that junior may have similar tooth problems.
Other problems with the way the teeth fit together may be affected by habits. Prolonged finger sucking, lip biting, or a pacifier habit may affect the way the teeth fit together and may make braces necessary if you want to correct these problems.
The American Academy of Orthodontics recommends the first orthodontic evaluation at age 7. Really what they are looking for is that all permanent upper and lower incisors are erupted. For some kids that may be as early as 6, others as late as 8 or 9. Once the permanent incisors and molars are erupted it is a lot easier to predict and anticipate how much space is available for the rest of the teeth to erupt and what problems may exist or develop.
The AAO does not recommend or endorse comprehensive treatment at age 7, but sometimes it may be wise to do some early interceptive treatment.
The final decision whether or not to start treatment will have to be made between you and your orthodontist.
Dietmar Kennel DDS
Lubbock KIDS Dental