# Multidisciplinary Planning in Orthognathic Surgery for Prosthetic Patients
## 1 Introduction  
The occlusal and aesthetic rehabilitation of jaw deformities in patients with a partially or totally edentulous maxilla is a challenging procedure [1]. Class-III malocclusion is characterized by a variety of skeletal and dental components, including a large or protrusive mandible, retrusive maxilla, protrusive mandibular dentition, retrusive maxillary dentition, and combinations of these components [2]. Class-II malocclusion is often characterized by a deficient mandible, leading to a convex profile, unesthetic facial proportions, and occlusion disharmonies. Class-II malocclusion has been further subdivided into division1 (div.1) and division 2 (div.2), depending upon the upper incisors' predication or retrolcination, respectively, although additional skeletal and dental differences exist between the subdivision types beyond upper incisor angulations [3]. The correction of malocclusions with a severe skeletal deformity generally requires surgery combined with orthodontic or prosthodotic treatment. An orthodontic camouflage or a pure prosthetic treatment may result in an unsatisfactory, unstable, and irreversible outcome [4, 5]. In cases of total or partial edentulism, a satisfactory reconstruction cannot be achieved via dental rehabilitation alone: to restore function and aesthetic balance, such patients require corrective jaw surgery. In orthognathic surgery planning for edentulous patients, prosthetic restoration is oftena compromise between the ideal restoration for stability and function on one hand, and aesthetics and appearance on the other hand [6]. In these cases, an interdisciplinary approach between the oral and maxillofacial surgeons guarantees a result that restores the aesthetics, function, and balance of the oral cavity and contributes significantly to improving the self-confidence and psychosocial well-being of the patient. The scientific literature has already discussed orthodontic treatment in dedentulous patients. In 1951, [PERSON] described the treatment of mandibular prognathism, with special reference to dedentulous patients: his approach included extraoral ramus osteotomy associated with the use of splints anchored to a cranial mask (to ensure adequate immobilization) and intraosseous sutures [7]. In 1953, [PERSON] and [PERSON] described the treatment of prognathism in dedentulous patients with an osteotomy of the body of the mandible, fixed with intraosseous sutures, and the use of acrylic splints, fixed with circumferential sutures, to place the mandible in a favourable position [8] (Figure 1). In 1954, [PERSON] and [PERSON] established the extraoral vertical ramus osteotomy (EVRO) technique to treat prognathism, a technique later modified in 1970 by [PERSON], [PERSON], and [PERSON] into the intraoral vertical ramus osteotomy (IVRO) technique commonly used by today's surgeons [9]. In 1952, [PERSON] started developing the bilateral sagittal split osteotomy (BSSO) to treat mandibular prognathism and retrognathia; perhaps the most astounding aspect of this technique is that the first 15 cases were reportedly treated under local anaesthesia and in a dental chair [10]. A malformed, or partially or totally dedentulous patient's treatment goal is functional and aesthetic oral rehabilitation, and it is, therefore, essential to consider this aspect in orthodontic planning. For this reason, evaluation with traditional orthodontic X-ray and cephalometric studies should be combined with traditional prosthetic studies, such as the assembly of the models in the articulator, diagnostic digital wax-up, computer analysis via 3D CT, virtual design, or the processing of surgical splints. In most orthognathic procedures, a surgical splint is an integral part of surgery, guiding the surgeon to position the maxillofacial skeleton in a pre-established ideal position. In addition, the position of the teeth and occlusion help guide the surgical movements.