Orthodontic intervention in the early mixed dentition: a prospective, controlled study on the effects of the eruption guidance appliance.

Introduction: A prospective, controlled cohort study was started in 1998 to investigate the effects of orthodontic treatment in the early mixed dentition with the eruption guidance appliance.

Methods: Occlusal changes were recorded in 167 treated children and 104 controls after they had reached the middle mixed-dentition stage. Treatment began when the first deciduous incisor was exfoliated (T1) and ended when all permanent incisors and first molars were fully erupted (T2).