If you are thinking about getting breast implants, you may have heard all kinds of stories about how they might leak or not look natural. For the best results, you need to get the right type of implant - which depends on the results you seek and what looks good on your body.
First of all, there are two overall types of implants - silicone and saline. Saline-filled implants are less firm, but their contents are sterile salt water, meaning if the breast implant pouch is pierced, it will be safely absorbed by the body. Silicone, on the other hand, has historically had problems with toxic leakage. Women under 18 should not get breast implants for a simple reason - their breasts may not have finished developing, and they may find they are happy with their natural breasts if they wait a few years. Women under 22 should not get silicone breast implants.
Additionally, there are two primary shapes of breast implants. A popular implant shape is a form-stable implant, sometimes called "gummy bear breast implants." These are shaped implants - so they may cause problems if they rotate. They have a thicker gel and are less likely to break, and will not lose shape if they do. The downside is the larger incision required. The alternative is round implants, which are the same shape all over, but make breasts appear fuller - so part of the decision there is the look you are seeking to achieve.
There are also smooth or textured implants. Smooth implants are softer and tend to move more with the pocket they are implanted into, which can look more natural. Textured implants are designed to cause scar tissue to hold the implant in place, which means they stay in place better.
The kind of breast implant that is right for you depends on what you want - so discuss your options with your surgeon and be honest about your goals.