Mandibular reconstruction--state of the art and perspectives.

The human mandible is a horseshoe shaped bone, anatomically divided into a body, angle and ramus. It is the only both movable and unpaired facial bone. The mandible defines the profile and appearance of the lower third of the face. Thus it contributes to facial contour, proper occlusion, mastication, airway support, deglutition and speech . Discontinuity of the mandible is caused by trauma, infection or the extirpation of a tumor and results in cosmetic deformity, psychological impairment and functional disability. The most common indication for mandibular reconstruction remains ablative surgery for advanced neoplastic processes. Reconstruction of complex three-dimensional composite bony and soft-tissue defects is a paramount for rehabilitation of vastly hindered form and function. In general, mandibular loss due to benign processes results in preservation of soft tissue. In contrast, mandibulectomy for carcinoma more frequently results in large bone and neighboring soft-tissues, muscles and nerve defects . The goals of mandible reconstruction are: establishment of mandible continuity, establishment of an osseousalveolar base, correction of adjacent soft tissue defects, and it has to provide sufficient durability and strength to allow resumption of daily activities. Restoration of a full thickness mandibular defect requires discontinuity of the mandible to be repaired with a graft of sufficient length to achieve symmetry and correct shape. Whereas the intraoral contours may be repaired by onlay bone grafting, guides to the shape of the lower border are few especially when the defect crosses the midline . Techniques for mandibular reconstruction could be classified into four categories: autogenous bone (avascular bone grafts, pedicled bone flaps, free vascularized osteomyocutaneous flaps, prelaminated and prefabricated bone grafts), osteogenetic distraction, alloplastic materials (with or without bone), tissue engineered grafts. Preoperative planning should include age, sex, smoking habits, alcohol consumption, comorbidities, etiology, dental status, time elapse from the cause of the defect, the localization and latitude of bony and soft tissues defect and a thorough evaluation of a patient's facial anatomy. The planning for surgery is highlighted by the physical examination of the face and its contours. Facial and dental measurements should be made (cephalometrics and anthropometrics). Imaging studies and digital data can also be used in the assessment as they could significantly contribute to mandibular reconstruction and implant stabilized occlusal rehabilitation. The treatment of these abnormalities requires the use of all applicable diagnostic aids . For those purposes these imaging techniques are widely used: panoramic ortopantomography, cephalometric radiography (anterioposterior cephalogram, submental vertex views). Multislice computerized tomography (CT) and magnetic resonance imaging (MRI) are also becoming popular in assessing maxillofacial abnormalities (Figures 1). With imaging techniques available today, 3-D models can be created to determine the need for soft or hard tissue reconstruction and/or augmentation (at demand), rehearse the procedure, or even to serve as a template for the custom creation of facial implants . Contraindications for elective procedure include infection, teeth problems, thinning mandible bone stock, bleeding disorders, unrealistic expectations, a history of radiation, or comorbidities.