Yes, they can burst--and the fix/clean-up (for silicone) can be staggeringly expensive, and the possible effects with silicone are still not fully understood--some women report auto-immune-type symptoms, though the research is inconclusive. However, bursting is not terrifically common, though it is a real danger, as is leakage, which can be worse because it's often not discovered for quite a while in silicone. Car accidents, blows to the chest, falling--all could cause a rupture or leak. It is recommended that women with silicone implants have an annual mammogram to check for leakage. Another thing to keep in mind is that implants do lessen the effectiveness of mammograms and self exams for breast cancer detection.Originally Posted by Simone_Locke
Saline implants, while safer, tend to give a more liquid/mushy feel, not natural feeling. When saline ruptures/leaks, you KNOW--the deflation is usually immediate. Silicone, while more natural feeling initially, can harden (though this is not common), leaving a very unnatural feel--kind of like a rock in your breast. Both types of implants can cause capsular contracture, which is hardening and tightening of scar tissue, which can be very painful.
Another thing to consider is breastfeeding--if you plan to have children, I would advise you to hold off on augmentation (or lifts) unless you can find a surgeon who is willing to take that extra time and effort to preserve the milk ducts and nerves around the areola. I've seen some really horrendous results in women who've had breast surgery that severed the ducts--they still produced milk, but with no intact ducts, mastitis developed, and in a few cases, this lead to horrific infections with terrible scarring. Also, because production of prolactin and oxytocin, which are necessary for let down and milk production, is dependent upon the nerves in the breast, severing of those nerves can totally preclude nursing. The popular "smiley" incision around the areola is most likely to cause you grief on this front, whereas the under the breast/armpit insertion usually allows for nursing later down the line.
Remember that breast implants often aren't permanent things--the rate of replacement/removal is pretty high, for a variety of reasons.
One of the most common complaints is change in/loss of feeling in the breast, sometimes increased sensitivity, but more often loss of sensitivity. This can be permanent.
Please don't think I'm trying to scare you out of it--a lot of women have it done and are very pleased with the results. But there are things to consider, and it's always better to go into things knowing as much as possible.
For what it's worth, I've always found b-cups to be perfectly lovely.
Kallie