What is the hardest/most firm filler on the market?

Belladerm is long lasting and made from the same material used to make artificial bone. It may not look or feel significantly different than the Radiesse though. If you really want a sculpted cheek bone, you might consider cheek implants. This surgery is less common since fillers have become popular, but gives a more permenant, defined look to the cheekbone. 

Thank you for your question.  Bellafill is a semi-permanent firm filler.  Since the Bellafill contains micro-spheres that don’t break down in your body, the effects of treatment are almost life-long.  I recommend scheduling a consultation with an experienced physician for optimal results.  All the best!

The fillers with the highest G' (lift capacity) on the market are Radiesse followed by Restylane Lyft.