Are silicone breast implants safe in the long run?

Yes. Implants are probably one of the most thoroughly researched devices implanted into human beings. On a lighter note- my kids played dodge ball with a couple of implants for weeks and they held up- far more intense potential damage than any mammogram, etc would do to an implant :).
Safest choice of all. Although saline implants are debatably "safer, " they can leak and require re-operation for replacement. Surgery is a risk--low but still! the newest silicone gel implants are a cohesive solid and cannot "leak" like older silicone implants. Plastic surgeons who decry the newest silicone implants have never cut one open. Older silicone can indeed leak but that is not what is being used now!
Debatable. Without sounding like a politician it really depends upon what you mean by "safe." silicone gel implants leak. They all leak minute amounts of silicone into your body. Your body may respond to this by producing a scar capsule around it that is much thicker than would be formed with a saline implant. This happens over years and may lead to the need for more surgery.
Yes. Any procedure carries risk but with proper care and follow up and early treatment of , silicone implants are safe.
Yes. In august of 2011 the fda revisited the question of silicone breast implant safety and reaffirmed that they are safe and effective. Though there is a controversial history, all major studies have reached the same conslusion. There are risks with every surgery and it is important to be familiar with the particular risks of breast implants, which your plastic surgeon should review in detail.
Yes. Currently there are no studies to show danger in using silicone implants for breast reconstruction or augmentation. Fda has approved silicone implants for both.