Is There a Sizing Difference when Switching Saline to Silicone?

Yes, there is a difference with how silicone gel implants sit on your chest wall (projection) compared to saline implants.  Silicone gel "mold" better to your chest cavity and therefore look "smaller" than the comparable saline implant.  Clear communication with your plastic surgeon is important in achieving the desired goals of the patient.  I like to communicate with patients with “goal” pictures.  During surgery, I use temporary sizers to determine the size/profile that will give the patient the look she is looking for. Trying to predict the size of the implant preoperatively is not ideal.  I think it is too much responsibility for the patient to choose the size of the implant.  Ideally, the surgeon would make that determination once he/she is in the operating room with sizers in and examining the patient in the upright and supine position.  

I agree with the other reviews.

If I have a patient changing implants to a larger size, I think one needs to go up at least 100cc to see a difference, and 150-200cc for a larger difference, depending on height, weight etc.

Technically there is no difference in the volume. However, in practice patients tend to feel as if the silicones are smaller and I will generally go up somewhere between 5-10%