Excerpt from Facial Alloplastic Implants, Mandibular Angle

Synonyms, Key Words, and Related Terms: facial alloplastic implants, mandibular implants, craniomaxillofacial reconstruction, facial proportions, facial asymmetry, maxillofacial prosthetics, facial topography, cephalometrics

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Over the years, techniques used in craniomaxillofacial reconstruction have become safe and standardized. These techniques are used to achieve an adequate functional and aesthetically pleasing correction of abnormal facial proportions or facial asymmetry. The treatment of these abnormalities requires the use of all applicable diagnostic aids. It also requires extensive presurgical planning to fully understand the 3-dimensional extent of the patient’s defect and potential for correction. This article discusses the surgical correction of mandibular angle defects, specifically deficiencies in the posterior aspects of the mandible. The focus is implantation of alloplastic materials into the mandibular angle (see Image 1).

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History of the Procedure: Identifying the exact origin of maxillofacial prosthetics is difficult, although most assume that prosthetic enhancement of facial features began before surgical procedures were common. Popp (1939) claimed that artificial eyes, noses, and ears were discovered on Egyptian mummies. The Chinese also made artificial facial parts from wax and resins. Pare (1575) was probably the first surgeon to use an obturator to close cleft palates. He illustrated a prosthetic ear made of paper or leather and a prosthetic nose made of silver attached to the face with a string. In 1880, Kingsley described the use of artificial parts to repair defects of the orbit, nose, and palate. A few years later, Martin (1889) described prosthetic devices for the replacement of missing parts of the maxilla and mandible. These two latter figures were the pioneers of maxillofacial prosthetics.

In 1894, Tetamore described a number of patients with loss of parts of the face, including the nose, which he had reconstructed with the use of prosthetics. The prosthetic material was made of a light plastic that was nonirritating and colored similarly to the skin. The prosthetics were secured to the face by spectacles. Tetamore is believed to have used cellulose nitrate to make these. In 1901, Upham used vulcanite to make prosthetic ears and noses. Kazanjian’s contributions, in 1932, provided the initiative for maxillofacial, dental, and plastic surgeons to work together for the betterment of facially deformed or injured patients. Today, the techniques that have evolved in maxillofacial surgery have become safe. Further, these techniques have applications in situations where even minimal deformity is present.

Problem:

Alloplastic materials

Dimethylsiloxane

Dimethylsiloxane (silicone) rubber implants with or without polymer fabric have been used in the augmentation of frontal, zygomatic, nasal, chin, parasymphyseal, paranasal, orbital, maxillary, malar, nasal dorsum, ear, and mandibular deficiencies.

Silicone rubber implants have been used for surgical applications since the 1950s. Silicone can be obtained preformed commercially or for custom shapes; room temperature vulcanizing silicone can be used. Silicone easily can be modified intraoperatively with a scalpel or scissors. It also can be fixated easily with a screw or suture to underlying tissues. This material has “memory,” which demands adaptation to bone contour in the “relaxed” state, since bending may lead to extrusion or bone resorption.

These implants easily are sterilized using steam autoclave or irradiation without damaging the material. Surrounding tissues do not react adversely to silicone, and only a thin fibrous capsule forms without ingrowth of tissue. Porous silicone implants and silicone bonded to Dacron have been used .....