Saline and silicone breast implants have different types of filler material.
Saline implants contain saline solution and silicone implants have silicone gel.
This explains why there is a difference in surgical incision length.
Saline implants need a smaller incision, whereas silicone implants need a slightly longer incision to insert the breast implants into the breast pocket.
The difference is quite small, but there are advantages and disadvantages for both.
Saline implants are placed into the surgical breast implant pocket without the saline solution.
This allows the plastic surgeon to roll up the empty saline implant and place it into the pocket.
The surgeon then fills the implant with saline solution through a fill tube.
The incision for a saline implants is usually about 2.
5-3.
5 cm or 1-1.
5 inches long.
Silicone implants are already filled with silicone gel before insertion.
You can't add or subtract any more silicone into the implant, which is why they are inserted completely filled.
The larger volume requires a slightly longer surgical incision to accommodate the implant.
The incision is typically about 4-5 cm or1.
5-2 inches in length.
When you are considering getting a breast augmentation, the difference in the length of the incision needs to be compared to the different feel and look of a saline versus a silicone breast implant.
The generally consensus is that a silicone implants have a slightly better appearance, since there is less rippling and wrinkling than a saline implant.
Also, silicone breast implants have a higher quality filler material, which allows the implant to move and feel much more like a natural breast.
Regardless of the incision type: areolar, breast fold/inframammary fold, or underarm/axillary incision; the silicone breast implant will require a longer surgical incision.
  In the end, the choice is yours, but a slightly longer incision is a small trade-off for a more natural appearance.