摘要
A reverse headgear is thought to be an effective .treatment approach for skeletal class Ⅲ malocclusion with retruded maxilla. Clinical studies have shown that the changes of occlusion are a combination of skeletal and dental changes： forward movement of the maxilla, proclination of the maxillary incisors, clockwise rotation of the mandible, and retroclination of the mandibular incisors. However, the undesirable dental effects, such as excessive mesial movement and extrusion of maxillary molars and labial tipping of maxillary incisors, have been reported. Most of previous studies have demonstrated that the best time for maxillary protraction is early mixed dentition. The skeletal effect decreases and the dental effect increases with age. So there is a need for an absolute stable anchorage for maxillary orthopedics to produce more skeletal change and less dental movement.
A reverse headgear is thought to be an effective .treatment approach for skeletal class Ⅲ malocclusion with retruded maxilla. Clinical studies have shown that the changes of occlusion are a combination of skeletal and dental changes： forward movement of the maxilla, proclination of the maxillary incisors, clockwise rotation of the mandible, and retroclination of the mandibular incisors. However, the undesirable dental effects, such as excessive mesial movement and extrusion of maxillary molars and labial tipping of maxillary incisors, have been reported. Most of previous studies have demonstrated that the best time for maxillary protraction is early mixed dentition. The skeletal effect decreases and the dental effect increases with age. So there is a need for an absolute stable anchorage for maxillary orthopedics to produce more skeletal change and less dental movement.
