[Bone anchorage in orthodontics. A review]

The achievement of absolute anchorage in orthodontics overcoming the reaction forces and moments has been problematic for a long time. This was caused on the one hand by the limitations of the devices available and on the other hand by the dependence on patient cooperation. The introduction of bone anchorage systems changed the traditional way of thinking on orthodontic anchorage. Whereas the application of anchor systems, such as palatal implants and onplants, has specific indications, bone screws with or without plates seem to have the potential of being used on a routine basis. However, appropriate data for more complete understanding of the biological and biomechanical background of this concept of orthodontic anchorage are still lacking. Furthermore, studies on the effectiveness of these systems when compared to the traditional orthodontic anchorage and based on large groups of patients are not available. Well-designed prospective clinical trials substantiating the evidence-based use of these devices are needed.