Of course, I understand the appeal of a one-and-done procedure that lasts a lifetime. The problem is two fold. First, if a permanent filler is used and there is an untoward or unwanted result, it is very difficult to reverse, since, unlike with HA fillers, there is no quick-fix dissolving enzyme to get rid of it. If you are skeptical, just do a thorough search under permanent filler complications. The next issue is that the results with the use of a permanent filler are not really permanent because you are not permanently the same. This means in two, five or ten years, with the natural aging process, you will lose bone, muscle and fat, which will undermine your supposedly "permanent" result and hence require additional treatments. What this all means is that with the use of a robust HA lifting filler for the mental crease you can expect to get up to two years of improvement, after which another round of treatment can be performed that would be in line with the natural changes in the muscle, fat and bone that have occurred. And finally, be aware that any kind of future manipulation of the skin in the region where permanent filler has been placed (whether it be from nearby dental work or even the appropriate use of an HA filler) can "razz" up permanent filler sites and potentially trigger late nodule or granuloma formation--which, not surprisingly make future filler injectors hesitant to go into that area even with HA fillers. You would be wise to thoroughly explore this with an experienced, board certified cosmetic dermatologist filler expert BEFORE jumping into permanent fillers. Hope this helps and best of luck.