Plastic surgeons and makers of silicone breast implants are gearing up for what they expect will be a boom in sales of the devices. The only question: How big of a windfall can they expect?

More than 290,000 women had breast augmentation surgery in the U.S. last year, most with the saltwater-filled versions that have been legal for years. With last week's Food and Drug Administration approval of silicone implants — generally considered to have a more natural look and feel — many in the industry believe a large percentage of women could quickly switch. In countries where both products are sold, silicone implants make up nearly 90 percent of the market.

Some doctors also predict that overall growth in breast augmentations could accelerate, as women waiting for approval of silicone implants visit their doctors and others with saline implants consider replacing them.

"There are a bunch of people who have been waiting to get the surgery because they were unsure" about silicone implants, said Dr. Richard D'Amico, a plastic surgeon in Englewood, N.J., and president-elect of the American Society of Plastic Surgeons. "But now that they have this kind of government approval, more are likely to feel comfortable enough to get it."

Any surge in silicone implants would be good news for surgeons such as Steven Teitelbaum, who met more than half a dozen patients considering breast surgery early this week in his sleek Santa Monica, Calif., office filled with photos of naked women and still lifes of fruit. Teitelbaum, who said his patient logs were already pretty full, said he believed that silicone was clearly the better choice for most women.

"I don't question what direction north is, where the sun sets, or if silicone is better than saline," he said, although he added that he was leaving the final decision to his patients.

A silicone surge also would be welcome for the two companies that dominate the trade, Mentor Corp. of Santa Barbara, Calif., and Allergan Inc. of Irvine, Calif.

Last year, the two companies each rang up about $230 million in sales of mostly saline implants. One big reason their profits will probably rise: Silicone implants cost twice as much as saline ones, or about $1,800 a pair, even though they're not much more expensive to make.

Those higher price tags, coupled with robust industry estimates about how many women will probably choose them and a possible bump in overall surgeries, led some Wall Street analysts this week to predict that implant sales could hit $2 billion a year by the middle of the next decade. Stocks of both companies surged after news of the FDA approval of the products, which had been banned for 14 years.

Both Mentor and Allergan have launched limited campaigns for their silicone implant products, including Web sites that were up hours after the FDA made its announcement late last Friday. Mentor's site is at mentor4me.com and Allergan's is at breastimplantstoday.com.

Both companies said they were confident their silicone implants were safe. They pointed to a growing list of studies over the past several years that had confirmed that. A seminal 2000 report by the Institute of Medicine, a division of the National Academy of Sciences, found no link between silicone implants and neurological or auto-immune diseases — concerns that had been raised in the past. The study did say silicone implants could cause complications such as infections and scarring.

Mentor said it believed that as much as 40 percent of its breast implant sales would be silicone products by this time next year. Allergan said it couldn't provide sales estimates.

Some women said they still harbored fears about silicone implants.

A 26-year-old patient of surgeon Teitelbaum said she decided on saline implants because she worried there might be lingering safety issues with silicone ones, even after the FDA's decision. After Teitelbaum delicately explained to her that many patients would probably see inferior results with saline implants, she told him she understood but had made up her mind.

"My dad was just diagnosed with cancer, and my mom is undergoing treatment for breast cancer," said the patient, who asked not to be identified because she had not shared her plans with all of her family and friends. "I don't want to take any chances."

David Buchanan, who has been practicing plastic surgery in Santa Barbara for two decades, said his office was receiving as many as a dozen calls a day from patients asking about the new silicone implants.

He said several patients told him this week that they would like silicone implants as long as he believed they were safe.

"I'm telling them all the same thing," he said. "I've been doing this a long time and I'm convinced they're not only a good choice, they're a safe choice."