I have a dent on my upper cheek when I smile. What kind filler and how much of it would be needed to resolve this? (photo)

I would proceed slowly. One syringe of filler placed in the deep layer, then wait 2 weeks and fill the superficial tissues. 

I personally have moved away from Radiesse as the results dont last as long as some of the newer fillers.  Voluma in particular would cause an elevation that may help you and it would last longer. It would need to be injected deep but be careful as the infraorbital bundle is close to that area.  See an experienced injector for that please. 

In my experience, such indentations that occur when you smile or move require a deeper injection with a more robust filler like Voluma or Lyft in order to make any appreciable difference. The problem isn’t superficial and doesn’t improve much with a superficial filler. 

This "dent" may be a dimple, which is muscle related and not really a dent in the skin.  I would suggest using a hyaluronic acid filler like Juvederm or Restylane in the subdermal plane if it is not tethered to muscle.  See an experienced physician injector to get the right examination and recommendation.  All the Best, Alexis Parker MD

Hi Currently, there are a lot of fillers like Sculptra, Restylane Lyft, Voluma and Revanesse that are worth considering for your concern. Sculptra builds up your collagen and work over time while the hyaluronic filler effects are more immediate. Radiesse may look a little stiff considering that the area is affected when your face is mobile.All the best, Justin Harper, M.D.