Chin implant vs genioplasty: which procedure would be best to give me a heart-shaped face? (Photos)

I agree that you don't need chin projection forward or any additional chin width.  A small amount of vertical height increase (which is best achieved with a sliding genioplasty as it is difficult to get a chin implant to stay in such a location) may help to balance your face, but you can't add too much height or you will get a witch's chin look.  If a heart shape is your main goal, reducing the horizontal width of your lower jaw (not just chin) is the best way to get there.  You could get a small improvement with botox to your master muscles, but, depending your ultimate goal, removing bone from the mandibular angle will give you the best result.  -Dr. Rolfes

You should consider shaping the back of your jaw. That's the best way to get a heart shaped face.  The chin looks fine and I would not suggest you adjust it.  Shaping the back of the jaw can be done through the mouth with no visible scars. Watch the video to learn more.

From your pictures I would not recommend a genioplasty. You may consider a buccal fat reduction where the incision is inside your mouth.  It is hard to tell from the lighting provided if you have a depression below the marionette line. That tea could be filled out with a customization of an implant. 
For sure a consultation is in order. 
Good luck with your search.
Dr. K 

Your photos do not show significant weakness of the chin. You do have pre-jowl depressions which can be easily corrected with filler. I would suggest a consultation with a surgeon experienced in fillers around the lower face and chin as an initial procedure. Fillers are definitely the place to start as this is quick, easy, reversible and will allow you to get comfortable with the ideal shape before you consider anything permanent.

You have a zero degree mandibular plane angle which is why your chin is vertically short and square. The correct procedure is a vertical lengthening bony genioplasty, with a midline chin narrowing, as you need your chin to become longer. Trying to position an implant on the edge of the bone is not going to work well and, unless it is a custom made chin implant that is specifically made to sit on the edge of the bone and only augments the central chin, your chin is also going to become wider. Conceptually adding volume from an implant works against making the chin more narrow. You need the bone reshaped and lengthened. 

 Hi, the answer is neither one would give you a heart-shaped face.  Most importantly, from these photos...your chin isn't weak and does not require augmentation by any method.  I have performed many facial shaping procedures using dermal fillers, silastic facial implants (cheek implants, chin implants), liposuction and/or facelifts for over 30 years.  From the photos, your cheeks are very flat in the front (actually concave) which makes the face appear relatively "square-shaped".  
 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.  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.
Hope this helps.