The silicone used in breast implants is pretty soft. The silicone used in facial implants is not. Have you squeezed a silicone chin implant in your fingers before? I think you will be surprised if you haven't. A 10mm jaw angle implant is not going to be substantially deformed out of shape. I find it humorous people believe that. There's x-rays online of jaw implants and you can see the implant sitting there in shape. There's after pictures of jaw implants clearly and sharply extending the vertical length of the ramus with no deformation. And so on.
The surgeons I've consulted in Europe that do jaw angle and custom mid-face implants all did Medpor exclusively with the exception of one. The two main reasons given were no infection risk (not true but they still said it) and that it's easier to customise for the patient. I was never told medpor is superior because it's harder and therefore deforms less under musculature pressure.
My opinion, and of course it's just my opinion, is the reason for poor jaw implant results is due to a host of other reasons. One being it's simply a challenge to get right. Another reason is due to muscles and soft tissue. The shape and size of the masseter muscle which lays on top of the implant varies substantially amongst individuals, for example.
Dr R to me:
"You are correct. Medpor gives a sharper and more defined look. It also produces minimal or none bone erosion. Silicone produces significant bone erosion particularly under the pressure of the strong masseter muscle. I will send you a rough draft explaining this and other comparative features."
He only prefers use silicone in areas where the ingrowth of medpor is actually a huge problem - probably the nasal area I am guessing.
In the documents he sent me, medpor is harder to modify in the surgical room, requires a bigger incision and is more complex to install. This is consistent with what other surgeons say about medpor, and why they prefer silicone - they sometimes even fold it to get it through the small incision, something not possible with medpor. Medpor is also more expensive than silicone.