I have previously dispelled the biologic misconception that facial implants of any material composition result in bone erosion. Improved biologic understanding through observations of indwelling facial implants using 3D CT scans show that the correct interpretation is implant imprinting of the bone. This occurs by the introduction of an implant into established biologic tissue boundaries which creates pressure on the surrounding tissues. The body responds to this pressure by relieving it through some tissue absorption which manifests itself as an imprint of the implant on the bone. It is a self-limiting benign process that has no clinical significance.
This is illustrated by a recent case of a square style chin implant that had been placed 20 years ago. The 3D CT scan showed that the central part of the implant was on the bone which left an imprint that could be seen when the implant was digitally removed. But the sides or wings of the implant was not on the bone (as is common with these wide old style square chin implants) and there was no bone imprinting at all.
But of greater interest is another common phenomena seen around facial implants, particularly along the chin and jawline, of bone overgrowth. (colored green) Such bone overgrowth is a response to the sustained elevation of the periosteal lining by the implant. (implant tenting) It is also representative of the body trying to heal the tissues around the implant…a biologic reaction that would not occur if inflammatory erosion was present. Notice that the bone overgrowth occurs even on the implant wings which are not on the bone.
This case example was of a patient going to undergo removal of his old chin implant and replaced with a custom wrap around jawline implant. The design of the jawline implant require a high quality 3D CT scan in which the shape, position and biologic reaction of the bone to the implant can be fully visualized.
Dr. Barry Eppley
World-Renowned Plastic Surgeon