Introduction: Inferior repositioning of the maxilla for correction of vertical maxillary deficiency has been found to be associated with instability and a tendency to relapse. This can not be completely controlled by using bone grafts as relapse commences before complete integration of the graft.
Methods: Improved stability was sought by using rules of geometry when displacing the maxilla down a sloping plane. Anterior and inferior sliding of the maxilla after a double 'M'-shaped Le Fort I osteotomy was performed to preserve bony contact at the medial and lateral maxillary buttresses. The plan of this technique was derived from model surgery when true changes at the Le Fort I level were visualized.
Patients: 15 patients with class III-malocclusion and anterior vertical deficiency of the maxilla were surgically treated using this technique.
Results: Bony contact at the maxillary buttresses after anterior and inferior displacement was possible in patients with less than 6mm movement in a sagittal direction. Only minor skeletal relapse (mean: 0.4mm) was observed in the follow-up period (mean 14.2 months).
Conclusion: The procedure should be considered whenever vertical maxilla relapse is of concern after anterocaudal displacement.