Today, silicone implants predominantly use jelly-like silicone gels, so-called cohesive gels. A leakage of the gel is impossible. The implants should be replaced if they cause problems or if the doctor finds damage to the implant shell during a check-up. In Germany, various certification bodies - including the TÜV (Technical Inspection Agency) - are responsible for testing the implants, which are breast augmentation.