[High construction bite activator treatment of anterior crossbite in mixed dentition]

We reported two cases of functional Class III malocclusion with a skeletal tendency in mixed dentition, treated by applying an activator with a high construction bite beyond the freeway space. A high construction bite, approximately 8 to 10 mm between upper and lower incisor edges was employed. By increasing the vertical separation of the construction bite to a specific range, the high construction bite intensified the activation of the myotatic reflex in the muscles of mastication as well the passive tension in the stretched perioral muscles through the viscoelastic properties. (Furthermore, the tension which was generated passively from the stretched perioral soft tissues, such as tendon and skin, would join the force). In these two cases, we could efficiently use the active and passive tension of the muscles by using an activator of this type, and gain the effective orthodontic force clinically.