Purpose. The current investigation was undertaken to study the three-dimensional (3-D) stability of simultaneous maxillary advancement and mandibular setback using rigid fixation. The study also aimed to analyse the factors involved in postsurgical relapse by evaluation of changes in various parameters. Patients. Twenty-five cases were evaluated of simultaneous Le Fort I maxillary advancement and mandibular setback using rigid fixation. Methods. Preoperative, immediate and 6-month postoperative skeletal and dental changes were analysed using 3-D cephalograms obtained from biplanar stereoradiography. Maxillary fixation screws were used as landmarks to evaluate postoperative stability. Results. The mean maxillary advancement was 3.7 mm. Relapse in the sagittal, vertical, and transverse planes was not detectable in the maxilla (p> 0.05). However, for an average mandibular setback of 5.7 mm, mean mandibular relapse was 1.1 mm or 19.3% anteriorly (p< 0.05). Surgical or postsurgical skeletal changes in the maxilla had no detectable influence on mandibular relapse (p> 0.05). Vertical alterations of the facial skeleton achieved surgically predicted the mandibular relapse (R2= 0.27, p< 0.05). Conclusion. Maxillary advancement and vertical changes of ± 2 mm did not influence the postoperative stability of the mandible. Relapse of the mandible seems to be influenced mainly by the amount and direction of the surgical alteration of mandibular position.
All Science Journal Classification (ASJC) codes
- Oral Surgery