Skeletal Class III surgical orthodontic case of mandibular first molars mesially moved using an anchor plate for closing space from the congenital absence of mandibular second premolars

The mandibular second premolar is a favored site for congenital absence of permanent teeth. If the second deciduous molar, which remains, were extracted, the space of about 10.0 mm would exist between the mandibular premolar and first molar. In cases where the labio-lingual position and tip of the mandibular incisors are appropriate or where the lateral profile is good, the second deciduous molar should be extracted, and the space of nearly 10.0 mm should be closed by mesial movement of the first molar. In addition, although absolute anchorage is necessary for such dynamic tooth movement, miniscrews implanted in young patients are less stable than those implanted in adults. In the case described herein, the first molars were moved using anchor plates approximately 10.0 mm mesial to the congenitally absent second premolar to close the space. Simultaneously, proper improvement of the tooth axis of the lingually inclined mandibular incisors was performed. The anchor plate was stable as an absolute anchorage even in young patients. It was possible to move the teeth reliably to the target position.