In the year 2000, 212,500 American women underwent breast augmentation, according to statistics published by the American Society of Plastic Surgeons. That number soared to 347,524 in 2007, an increase of 64 percent.

The reason? It may be because Nov. 17, 2006 marked the end of the Food and Drug Administration's nearly 15-year ban on silicone gel implants. Some 35 percent of the record implant total in 2007 comprised silicone gel; the rest were made of saline solution.

Back in 2006, with less than two months of silicone gel implant availability, the number of augmentations for that calendar year totaled 329,396. That was a 13 percent increase over 2005 totals, which made breast augmentation the top surgical cosmetic procedure performed by ASPS member surgeons for the first time in history.

"Breast augmentation has always been among the top five surgical procedures, but until now has never been No. 1," Dr. Roxanne Guy, then the ASPS president, said after the 2006 numbers came out.

"With the return of silicone breast implants to the U.S. market, it is likely the number of breast augmentations will continue to increase. Some women prefer the look and feel of silicone implants and were waiting for the FDA to make its decision."

Surgeons expected the number of silicone gel implants to soar, but the growth has been gradual. Before the 1992 ban, use of silicone gel implants far outpaced that of saline implants. Silicone gel implants are less likely to leak or wrinkle and have a softer, more natural feel. (On the other hand, saline implants cost much less, and the valves through which they are filled with salt water make them adjustable during the surgery itself.)

But non-scientifically based reports began to surface in the late 1980s that the silicone gel implants were not safe. The ban, initially voluntary, was imposed amidst lawsuits and a media brouhaha over the reports that the implants could rupture and lead to such systemic disease as cancer, chronic fatigue syndrome and rheumatologic problems. In lifting the ban, the FDA said that numerous studies since its implementation had shown no such link.

From that viewpoint, "what happened was a good thing. The silicone gel implant became the most studied device in medicine," said Dr. Kenneth C. Shestak, director of the UPMC Center for Cosmetic Surgery.

"We thought there would be a stampede back to silicone gel," he added. "The numbers have built slowly."

However, Dr. Shestak said, "the majority of my implants are silicone gel implants. It's probably 70 percent to 30 percent."

At the Shadyside-based plastic surgery practice of Dr. Leo H. McCafferty, a clinical assistant professor at the University of Pittsburgh Medical School, 60 percent of the patients seen since the ban was lifted still chose saline.

"We're not pushing one over another," said Dr. McCafferty, a member of the board of directors of the American Society for Aesthetic Plastic Surgery.

"I thought it would have gone totally silicone, but that has not been the case," said Dr. Michael White, a plastic surgeon at Allegheny General Hospital and partner in the practice of Plastic Surgery of Pittsburgh. "I think it's 50-50 in my practice."

Despite the softer feel and look and stronger durability of silicone gel implants, the saline implant is the better choice in many cases.

"When someone who is heavier or whose breast tissue hasn't fallen and who has not only more breast but overlying soft tissue, then saline will provide a natural result," Dr. McCafferty said.

"For gel, [the better candidate] is the patient who has very thin overlying tissues, small breasts that have fallen slightly."

Still, Dr. McCafferty added, "these are very broad generalizations because every patient is different and there are many, many considerations."

Some of them are each patient's anatomy, their desires, and their expectations.

For example, if you think augmentation will fulfill someone else's desire, the surgery is not for you, according to the ASPS Web site, www.plasticsurgery.org. But the surgery will improve the balance of your figure and may enhance your self-image and self-confidence.

Other considerations include potential risks and the fact that the implants may someday have to be replaced.

The risks include all of those that go with any surgery -- such as unfavorable scarring, infection, bleeding or poor healing -- and others particular to breast enhancement itself. The latter include loss of nipple sensation, breast asymmetry, deflation and hardening of the capsule, or scar tissue, that forms around the implant shell.

The two American manufacturers of breast implants, Allergan Inc. and Mentor Corp., offer lifetime replacements of the prosthetics and provide some coverage of surgical costs.

"Nothing that a doctor puts inside of a patient's body lasts forever," said Dr. Shestak. "Not a heart valve or a pacemaker or a total hip. A breast implant is no different."

• For women considering breast augmentation, also known as augmentation mammaplasty, these sites are recommended:

www.plasticsurgery.org/patients_consumers/procedures/AugmentationMammoplasty.cfm

www.breastimplantsafety.org