Fillers can be used to fill in the cheeks but some do a better job than others. When I see a patient who has loss of volume in the face I immediately consider volume replacement and my first choice is Sculptra. I fill the sub-malar area to start and then use it in the mid-cheek and naso-labial folds. While you can use the HAs such as Juvederm or Restylane for filling the cheeks these agents are relatively short lived and the volumes required make their use quite expensive. Radiesse is slightly better in this location but has the tendency to separate.
Sculptra requires at least three separate sessions of 1-2 vials and stimulates your own collagen. The results last two years or more once full correction is achieved. I have my patients return in a year for maintenance "tweaks". If my patient is in need of a "quick fix", I would use an HA but I would want to start Sculptra at the same time for longer lasting results.
I hope this helps.