Phase I treatment is started when the patient still has some baby teeth. Phase I treatment generally takes 6-12 months. Phase I treatment is helpful in guiding eruption of permanent teeth and correcting some bad bites that would be difficult to correct at an older age.
It is usually necessary to continue with Phase II treatment once all the permanent teeth erupt to finish bite correction and alignment. Treatment time with Phase II is usually less than it would have been had the patient not had Phase I treatment.