Abstract: An implant for osteosynthesis used in the stabilization of fractured bone of the mandible. The plate consists of apertures through which the plate is secured to bone using surgical screws. The apertures are connected by (a) two lateral bar sections running approximately parallel to the long axis of the mandible and (b) two cross bar sections intersecting each other near the centroid of the plate and at acute angles to the lateral bar sections. The plate design can be modified to accommodate patient anatomy depending on the type of bone it is designed to stabilize. Design and size parameters of the fixation plate can be customized to each individual patient using a customization software application to determine the least invasive fixation plate that will provide adequate functioning in stabilizing the bone fracture to a degree that will allow safe bone healing. The invention includes a method of design of osteosynthesis plates using shape optimization for different types and locations of fractures.