due to extreme difficulty in establishing a rigid anchorage for molar intrusion.

thesis cairo university

Skeletal Anterior Open Bite is one of the most challenging malocclusion to correct. The complexity of this malocclusion is usually attributed to its multifactorial nature, where combinations of skeletal, dental, soft tissue and sometimes functional factors interact. Open bite is defined as a state in which the upper and lower teeth are separated when the jaws are closed completely, and generally refers to an anterior open bite in which the upper and lower anterior teeth do not occlude at a centric occlusion. Anterior open bite is often caused by a downward rotation of the mandible and/or by excessive eruption of posterior teeth. It is characterized by longer vertical dimensions and steep mandibular plane.
Control of the vertical dimension by intruding both maxillary and mandibular molars and facilitating counter-clockwise rotation of the mandible is the key to manage anterior open bite malocclusion treatment.
Traditional biomechanical techniques such as the use of the fixed mechanics and vertical elastics, passive bite-block, an extra-oral anchorage such as high pull head gear or vertical pull chin cup as well as posterior active vertical corrector with magnets, have several disadvantages such as rely on patient co-operation and ineffective control of the molars intrusion, especially in adult patients due to extreme difficulty in establishing a rigid anchorage for molar intrusion.
In the recent years, numerous publication have introduced novel way of reinforcing anchorage using a variety of temporarily anchored
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Introduction 
devices in bone and were collectively named skeletal anchorage system (SAS). The use of such skeletal anchorage system, is now growing in popularity because of their ability to provide absolute anchorage, lack of patient‘s compliance, their relatively small size offering a versatility of insertion sites, ease of insertion and removal, ability to be immediately loaded, as well as their few complications and low cast.
Concurrently, the use of such devices has expanded the boundaries of orthodontic treatment, where they are now heavily applied to many clinical situations, including anterior segment retraction, mesial/distal movement of multiple posterior teeth, anterior teeth intrusion, posterior teeth intrusion, intermaxillary traction as well as orthopedic traction.
Despite the fact that many reports have been published regarding the successful use of SAS in the treatment of skeletal open bite.
The present study was undertaken to compare and investigate the use of two different miniscrew anchorage assemblies as anchorage units for intruding maxillary posterior teeth in adults and their subsequent effects on closing skeletal anterior open bite.