A lip-activated appliance in early orthodontic treatment.

After reviewing the modes of action and types of lip-activated appliances, three cases were reported. A mandibular lip-activated appliance was used to gain space among the incisors and mesial to the mandibular permanent first molars; a maxillary lip-activated appliance was used to correct an anterior crossbite by labial movement of the incisors; and a modified lip-activated appliance was used to expand maxillary molars buccally.