Orthodontic space closure of every single patient should be planned individually based on the diagnosis and treatment plan. Failure on this procedure due to anchorage loss will inhibit correction of the bimaxillary protrusion because mesial movement of the posterior teeth occupied most of the premolar extraction space. The diagnosis and treatment plan should be considered carefully especially those of the amount of crowding, anchorage, axial inclination of canine and incisors, midline discrepancies and left/right symmetry, also the vertical dimension. In general there were two methods of space closure, non-sliding mechanics and sliding mechanics. To achieve space closure with the movement of the teeth desired, we must planned the anchorage control strategies. Differential force system are an excellent means in anchorage control, where the M/F ratio of the anchor teeth must be stronger then the teeth which moved. |