An analysis of factors influencing stability of surgical advancement of the maxilla by the Le Fort I osteotomy.

Skeletal stability after maxillary surgical advancement was studied in 30 patients. Postoperative movement of all measured skeletal and dental points were on the average negligible. Equal stability was seen in maxillary advancement alone and with concomitant mandibular surgery. Eight cases examined individually showed larger than desired postoperative movements. In six of these cases the undesirable postoperative changes were secondary to undesirable preoperative orthodontic flaring of the incisors. The Begg orthodontic technique, because of its tendency to axially rotate teeth, was shown to produce more variability in tooth position than edgewise orthodontics. This study confirms that no preoperative flaring of the maxillary incisors should be attempted; instead, the teeth should be retracted and placed over basal bone with a normal axial inclination. Occlusal correction should then be accomplished by surgery. Suspension wires and bone grafting are sufficient to obtain skeletal stability in cases of maxillary advancement up to 11 mm. In cases where the surgery is more complex, rigid fixation is recommended.