Ms. Tillman said the agency had determined that silicone-gel-filled implants are safe and effective for women 22 or older who receive the appropriate follow-up care. She added that it was not clear how using the devices without following the recommendations may affect safety and efficacy. The two largest plastic surgery associations said they strongly advise members to adhere to the guidelines. Mentor Corporation, which makes silicone implants, said it supports the product labeling. The other implant manufacturer, Allergan Inc., said that it encourages physicians and patients to follow the recommendations and that it offers training for physicians to understand them. About 330,000 cosmetic breast augmentations were performed in the United States in 2006, up from about 291,000 in 2005, according to statistics from a survey of doctors conducted by the American Society of Plastic Surgeons. These numbers do not include patients who had implants for reconstruction after breast cancer.