Do cheek implants move naturally with your facial movements (when smiling, talking) and can people tell if you have them?

Cheek implants and facial movement. No they don’t move which is the same as the bone you have. If properly done by an experienced surgeon you should be very happy. You can always try a filler first. 

Cheek implants are placed on the bone and do not move with facial expression changes. I prefer to place a screw in each implant to secure it to the bone. Cheek implants are permanent and yet, can be easily removed under local anesthesia. If you are tired of getting yearly fillers, cheek implants are a good option.

Yes, cheek implants can give natural looking results and can be customized. However, volume of the cheeks can be created with well-placed fillers (Voluma, Radiesse, Bellafill) and Sculptra which would allow you to try on the look before committing to a permanent option like implants or fat. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer

Cheek augmentation with implants should appear natural if done correctly.  If too large an implant is used, the results can appear unnatural.  The face should move normally with cheek implants in place.  The implants are placed directly on top of the bone, so all of the tissues over the bone should continue to move over the cheek bone with the implant in place.  

No, properly placed cheek implants do not move, since they are a bony augmentation. The implants are placed directly over the bone underneath the periosteum and underneath the facial muscles and subcutaneous tissues. For many examples and more information, please see the link and the video below

 Hi, I have performed many facial shaping procedures using dermal fillers, silastic facial implants (cheek implants, chin implants, lip implants), liposuction and/or facelifts for over 30 years.  Non smiling, resting photos of your face from the front and side would helping the evaluation.  Yes, if silastic cheek implants are properly placed below the cheek bone periosteum they will look and feel like very natural whether smiling or moving your mouth.
  Following my beauty principles, women look the most feminine, youthful and attractive with heart shaped faces.  Heart shaped faces have cheeks that are full and round in the front.  If the cheeks are either flat or concave in the front, cheek augmentation with a dermal filler or using silastic cheek implants for a permanent enhancement will create full, round cheeks that will feminize the entire face.  
 Malar cheek implants are placed over the cheek bone (Malar Bone) and as such are able to re-shape the cheek(s).  In contrast, Sub-malar (means below the cheek bone or Malar Bone) do not have the ability to re-shape the cheeks themselves but rather elongate the cheeks vertically which will not provide the necessary forward cheek projection to create a heart-shaped face in a woman or a chiseled angular face in a man.
  Cheek implants can be placed using several different approaches but using a small incision on the inside of the mouth remains the "gold standard" and most accepted manner of placement.  This technique places the silastic "cheek implant" on the cheek bone itself below the tissue covering of the bone in what is called an "implant pocket or space".  The tissues are closed in layers from the inside outward and a double water tight closure is done along the incision line. 
 I have placed silastic cheek implants for 30 years in military, SWAT, LE, professional fighters, as well as actors and many regular people who are active.  When placed below the covering of the bone and when the layers of the cheek are closed from the inside out, there is no need for fixation screws or sutures in my humble opinion.  I do ask that all my cheek implant and chin implant patients sleep on a U-shaped pillow for 1 month following the surgery.  In addition, I have had the opportunity on numerous occasions to replace silastic cheek implants (placed by others) that had been screwed into the cheek bone.  During the replacement it was evident that the metal screws pushed right through the soft implant as it was tightened down on the hard cheek bone.  Which makes perfect sense.  So in the long run, these fixation methods alone are no guarantee that the implant won't move.  Proper placement, proper implant pocket creation and meticulous closure of all the tissues layers is what is required in my humble opinion.
 In contrast, a sub-malar cheek implant is as the name applies placed below the cheek bone thereby being incapable of actually changing the shape of the cheek bone itself and since the implant isn't placed below the periosteum, the implant must be sutured to the tissues themselves which is why I do not use or recommend sub-malar cheek implants. 
There are many faces that have excess fat over the cheek area which hides the "true" shape of the cheeks below.  In addition to obstructing the cheek shape, this excess fat will sag prematurely as it is pulled by gravity at an accelerated rate versus a face without excess fat in the mid face.  Removal of the excess fat, with liposuction, is key when properly shaping the cheeks with cheek implants.  I have used this in combination with cheek implant surgery for 30 years.  In my experience these procedures when combined in a face with excess fat in the mid face are extremely safe, effective and reliable in the aesthetic results they produce.  Be sure to see an expert facial shaping surgeon.
Hope this helps.

Cheek implants are placed on the bone and then attach to the underlying bone which does not move. If proper size is placed in the correct location the will look natural regardless of facial expresssion.

Cheek implants, unlike fat injections, are not mobile.  They lie on top of the cheek bone and give the effect of having larger cheek bones.  They look natural if done expertly.  Seek out an opinion form a board-certified expert.  Best wishes.