SKELETAL AND DENTOALVEOLAR STABILITY OF LE-FORT-I INTRUSION OSTEOTOMIES AND BIMAXILLARY OSTEOTOMIES IN ANTERIOR OPEN BITE DEFORMITIES - A RETROSPECTIVE 3-CENTER STUDY

A sample of 267 patients with maxillary hyperplasia, a Class I or Clas s II/I occlusion and anterior Vertical open bites, collected from thre e different institutions, was analysed regarding stability after surgi cal corrections. Skeletal and dento-alveolar stability of the maxilla, and positional changes of the mandible and of the incisors were evalu ated. All patients underwent Le Fort I intrusion osteotomies and in 92 patients segmentation of the maxillae was performed. An additional bi lateral sagittal split advancement osteotomy was performed in 123 pati ents. Intraosseous wire fixation was used in 153 patients and rigid in ternal fixation in 114 patients. Cephalometric radiographs were collec ted before orthodontic treatment, before surgery, immediately after su rgery, one year postoperatively and at the latest follow up. The mean follow up was 69 months (range 20-210 months). It can be concluded tha t patients with anterior open bites, treated with a Le Fort I osteotom y in one-piece or in multi-segments, with or without bilateral sagitta l split osteotomy, exhibited good skeletal stability of the maxilla. R igid internal fixation produced the best maxillary and mandibular stab ility. The mean overbite at the longest follow up was 1.24 mm and a la ck of overlap between opposing incisors was present in 19%. The overbi te did not differ significantly between the different treatment proced ures, probably due to compensatory movements of the mandibular and max illary incisors.