Medpor is a commonly used implant for the reconstruction of moderate to severe chin retraction, short mandible (micrognathia), and some congenital skeletal defects. It comes in diverse models and sizes, thus meeting the face shape requirements of an overwhelming majority of patients. In addition, it is highly customizable. Medpor is made up of biocompatible polyethylene and is riddled with fine net holes, which enable the regeneration of capillaries and closely combine with the skin, thus effectively lowering the incidence of implant reaction or infection. Every model of Medpor is designed in a particular U-shape with two pieces and conforms to the physiological characteristics of the human skeleton. Medpor allows the implant to enclose the interface with the mandible, thus addressing the depression or stepped deformity at both sides of the chin that may arise in a traditional one-piece silicone implant; further, it is long enough to fixate at a 45° chin angle to elongate the face and change the proportion of mid and lower face in the frontal view. Moreover, for some patients with a deviated jawbone, such a two-piece implant can realize a flexible height or side-to-side adjustment to modify a chin deviation and other complex esthetic problems, which obviate the risks of genioplasty or chin osteotomy.
The strength of Medpor is similar to that of human skeletons, and it provides similar support to the skin to present a natural impeccable curvature of the chin. The implant needs to be fixated by titanium bone screws that allow the random height or angle adjustment of implants to elongate the face or sharpen the chin and also tolerate a gross outer force collision without deformity or dislocation, thus partially replacing the protection function of cranial bones. Currently, it is the most secure and safest chin implant . Bone screws for fixation are also biocompatible materials and do not need to be removed or replaced during the lifetime.