I find it very interesting that the material used was apparently deemed as safe by the UK medical authorities. The industry I work in is extremely stringent when it comes to standards and certification, but, there is no absolutely hard and fast rules as to what is fine and not fine, it is down to their customer's auditors to have the final say. So, the question would have to be for me, have the goalposts changed? Or, is this just a massive grey area which can be argued ad infinitum?
As a personal thought though, sure any bodily implant presents a risk of some sort?