It's best for the orthodontist to see children by age 7 to advise if orthodontic treatment is recommended, and it can also be the best time for that patient to be treated. The first permanent molars and incisors have usually come in by that age and crossbites, crowding, and other orthodontic problems can be evaluated. When treatment is begun early, the orthodontist can guide the growth of the jaw and guide incoming permanent teeth. Early treatment can also coordinate the width of the upper and lower dental arches, gain space for permanent teeth, frequently avoid the need for permanent tooth extractions, reduce the likelihood of impacted permanent teeth, correct thumb-sucking and other oral habits, and eliminate abnormal swallowing or speech problems. In other words, early treatment can simplify later treatment.