[Implant size and soft tissue behavior in different facial areas. An experimental study]

In order to predict augmentation results reliably in facial contour improvement, the thickness of the soft tissue and its deformation was reliably determined in 15 fresh cadavers after subperiostal insertion of self-made silicon implants ranging from 2 to 14 mm in diameter. Direct percutaneous measurements were made on the forehead, dorsum of the nose, malar bone, angle of the mandible, and the chin. Each region was subdivided into three zones. In 50 normal-weight subjects, the thickness of the facial soft tissues was also recorded sonographically with the aforementioned measuring points. The soft-tissue diameters decreased in the following order: malar region (8-14 mm), chin angle of the mandible-forehead dorsum of the nose (1-2 mm). In the malar region, the angle of the mandible and chin, there was a step-wise, significant compression of the soft tissues, which reduced the augmentation effect by up to 20% after subperiostal insertion of implants of up to 8 mm in diameter. Larger implant diameters (10-14 mm) no longer increased the compression effect. The thickness of the facial soft tissues at the implantation site was of decisive importance, since it defines the degree of buffer capacity. Preoperative sonographic measurement of soft-tissue thickness could therefore help to predict the augmentation result better; in the presence of a thick soft-tissue mantle (from 10 mm), we recommend selecting a 20% greater implant thickness in order to equalize the buffer effect and to avoid subcontouring.