Silicone breast implants, banned for most U.S. women since 1992 due to health concerns, came under scrutiny again on Monday as a panel of health experts began weighing whether new data shows they are safe enough to be widely marketed.

A three-day meeting began with emotional testimony from patients, doctors and interest groups both supporting and opposing implants made by Inamed Corp. and rival Mentor Corp.

Many women and plastic surgeons say the silicone gel-filled devices, which are widely available in other countries, have a more natural look and feel than saline-filled breast implants.

But some patients are convinced that leaking silicone can cause sickness, although studies have failed to find a link to cancer, lupus or other chronic diseases.

In October 2003, an advisory panel said Inamed’s silicone implants were safe enough to be sold, but the Food and Drug Administration rejected the application and asked all makers to collect more data on when and how often the devices break.

The agency’s panel of outside experts will review the new data at this week’s meeting. Testimony from patients and doctors was due to go until late Monday evening.

“This meeting is not intended as a general referendum on silicone breast implants,” Miriam Provost, acting director for the FDA’s device evaluation division, cautioned the public and the advisers. “We will make our decision based on the scientific data.”

Still, women who were either satisfied or horrified at their implant experiences urged the panel to take their side.

“My breasts remain soft and natural looking, which is important to me,” patient Valerie Hartwell said in testimony read by her doctor Caroline Glicksman from New Jersey. “I am so pleased with the results.”

Both Inamed, which is being bought by Medicis Pharmaceutical Corp., and Mentor have said the implants they make now are sturdier than those of the 1970s and 1980s, adding that the silicone gel is stickier and less likely to migrate.

Other patients and family members warned of suicide risk, extreme fatigue and silicone leaking from their scars.

“I don’t want anyone else to suffer this way,” Susan Helman of Florida said, adding that she suffered from headaches and nausea after silicone and gel-forming platinum catalyst leaked from her implants.

FDA staff reviewers last week questioned new submissions from both companies, which they said failed to shed light on how likely the devices were to break.

Inamed’s analysis assumes “the implant does not age” so that the number of broken devices is the same each year, the reviewers said.

FDA staff cited estimates that anywhere from 21 percent to 74 percent of the silicone devices could break after 10 years.

Breast cancer survivors and others needing breast reconstruction or implant replacements have been able to get silicone implants since the 1992 ban through clinical trials.

Between 25,000 and 30,000 U.S. women have been getting silicone implants each year as part of the trials, Inamed officials have said.

According to the American Society of Plastic Surgeons, more than 264,000 cosmetic implant procedures and nearly 63,000 breast reconstructions were performed in 2004.

Inamed shares were down 27 cents at $65.32 on the Nasdaq market in early trading. Mentor shares were 25 cents higher at $34.44 on the New York Stock Exchange.