Managing the developing Class III malocclusion with palatal expansion and facemask therapy.

One of the most significant changes in the area of early treatment in recent decades concerns managing the developing Class III malocclusion. Twenty-five years ago, early intervention for Class III malocclusion was not common in the United States. Management usually involved chincup appliances to restrain mandibular growth, camouflage techniques to advance maxillary incisors and retract mandibular incisors, or waiting until growth ceased to pursue orthognathic surgery. The development and refinement of maxillary protraction with facemask and palatal expansion have provided a predictable and effective approach to managing treatment that was once considered difficult. Most patients with developing Class III malocclusions display anteroposterior and vertical maxillary deficiency with a normal to slightly protruded mandible and average to deep overbite. These patients are managed well with maxillary expansion and facemask therapy. Although this approach has been described as maxillary protraction, the correction occurs by a combination of skeletal and dental movements in both the anteroposterior and vertical planes of space. A large range of responses is reported in the literature, with some articles noting significant maxillary advancement and others reporting minimal or no change with treatment. This disparity in response might be due to variations in treatment protocol including the design of appliances, the number of hours worn per day, and the overall treatment time. Although the average maxillary advancement in our study was 3.3 mm, 6 of 21 patients showed maxillary advancement from 5 to 8 mm. Similarly, when the average SNA change was 2.35°, 5 of 21 patients showed SNA changes of 4° to 5°. Mandibular clockwise rotation accounted for 25% of the total correction, as did anterior maxillary tooth movement (20%-25%).