Silicone gel-filled implants: comprised of a silicone outer shell filled which is filled with silicone gel. If the silicone filling leaks, the gel will remain in the shell or leak into the breast augmentation pocket. Implants filled with leaking silicone may or may not collapse. Patients who choose this type of implant should see a doctor more regularly than saline implants. You can check the condition of the implant by MRI or ultrasound.