Profile changes following maxillary impaction and autorotation of the mandible

Abstract

Objective: The aim of this study was the evaluation and prediction of profile changes after Le Fort I osteotomy including maxillary impaction and subsequent autorotation of the mandible.

Materials and methods: A group of 42 patients (32 female, 10 male) underwent a Le Fort I osteotomy with posterior impaction after preoperative orthodontic treatment. No surgical intervention in the mandible was performed. Pre- and postoperative lateral cephalograms of each patient were analyzed in two steps using the Wilcoxon and Mann-Whitney U test. All patients were evaluated for vertical and sagittal skeletal and soft tissue changes. These results led to further classification into three groups according to the type and extent of maxillary impaction. These groups included parallel impaction, posterior impaction with additional anterior subsidence, and posterior impaction only.

Results: The results of the first evaluation step revealed that the chin had advanced on average by 79%, while the lower face was shortened by as much as 70% in the pogonion point. However, the second evaluation showed that the type and extent of maxillary impaction led to significant changes in these parameters. Parallel maxillary impaction resulted in 100%, posterior impaction in 80% and posterior impaction with anterior subsidence in 50% advancement of the mandible in the pogonion point in relation to the distance covered during impaction.

Conclusion: This study showed that the change in the facial profile caused by autorotation of the mandible after Le Fort I osteotomy and maxillary impaction can be predicted in relation to the dimensions of maxillary impaction.