Difference definitely exist.
Chin implants and genioplasties have advantages over one another in different situations. In most situations, a chin implant is easier, quicker and less expensive (I use them in over 95% of the chin procedures that I perform). However, in some circumstances, I feel that a genioplasty is indicated. What you describe is a situation that would benefit from not only more projection, but also increase in vertical height of the chin. This situation is when I feel that a genioplasty is indicated and provides a more natural appearance after surgery. Please seek a consultation with an experience surgeon who can discuss both options with you, and see the reference below.
J. Frodel, J. Sykes, J. Jones: Evaluation and treatment of vertical microgenia. Arch Facial Plast Surg. 6 (2):111-119 2004
Chin implant versus sliding genioplasty
Basically, it's related to the amount of deficiency that is present. Small to medium deficiencies of the chin area are easily and effectively corrected with the simpler chin implant operation. Severe deficiencies of the chin area usually do better with the sliding genioplasty.
I do a lot of both, but prefer chin implants for less severe cases. Less surgery, less expense, less healing, more reversible.
Joe Niamtu, III
Cosmetic Facial Surgery
Chin implant versus genioplasty
A genioplasty is usually performed when there is a significant amount of advancement of the mandible a must be performed, and the teeth did not fit appropriately. Sometimes the upper jaw and the lower jaw are broken and reset. This is performed as an inpatient procedure in the hospital by an oral surgeon.
A chin implant is done for cosmetic purposes under local anesthesia as an outpatient surgical procedure. Chin implants are manufactured in a variety of sizes and shapes, they are placed through a sub mental approach by a plastic or facial plastic surgeon, and can be removed if ever necessary.
Chin implant vs genioplasty
A chin implant will only increase chin projection in the anterior direction. You can lengthing, shorten, advance, decrease, or move sideways the chin with a genioplasty. Donald R. Nunn MD Atlanta Plastic Surgeon
Are there cases where chin implants are more appropriate than a sliding genioplasty and vice versa?
Yes, there is a difference. A chin implant will project the chin forward by making an incision under the chin to place a stylastic implant. A genioplasty is cutting the bone. Chin implant is reversable.