RecruitingProcedureRegistry to Collect Data on Patients Undergoing Segmental Mandibular Defect Reconstruction Following Oral Squamous Cell Carcinoma Resection and Drugs-induced OsteonecrosisProspective will be collected in a minimum of 300 patients presenting with an acquired segmental mandibular defect ≥ 2 cm secondary to OSSC removal and drugs-induced osteonecrosis, and who require mandibular reconstruction.