I assume when you refer to an ePTFE (Goretex) forehead implant you are referring to the newer performed (standard) forehead implants by Implantech. These have been developed specifically for moderate augmentation in women that seek a rounder/more convex forehead shape. Such implants can be effective provided their shape corresponds to what your forehead augmentation shape goals are. Like all non-custom forehead implants there is always the risk of edge visibility of the implant which often isn't evident until months later when the swelling has fully subsided and the shrinkwrap effect of the forehead tissues has occurred. In some cases a custom forehead implant may be better. The advantage of any forehead implant is that it is completely reversible. Besides the unpredictability of fat graft survival in the forehead, any contour irregularities can be very hard to solve and there is little recourse for reversing undesired forehead fat grafting results.