The head of the national Centers for Disease Control promised Thursday to listen with an open mind as experts and activists convened for a hearing on proposals to require AIDS tests for health-care workers.

In the hearing the CDC is seeking advice and criticism from nearly 100 representatives of groups as diverse as the guerrilla protest organization ACT UP and the American Medical Association."The CDC goes into this with a completely open mind regarding what more, if anything, needs to be done to minimize the risk of AIDS to patients in doctors' and dentists' offices," said Dr. William Roper, director of the CDC.

Concern over patients' risk of getting AIDS infection at the doctor's office grew last summer with the disclosure of three cases among patients of an infected Florida dentist.

The AMA and other groups have sharply criticized the idea of requiring health-care workers to undergo AIDS tests.

Dr. Nancy Dickey, an AMA trustee, said in a statement prepared for the hearing that "mandatory HIV testing for health-care workers would be no more successful . . . than mandatory testing for marriage license applicants."

"A physician who has a transmissible and fatal disease should not place his or her patients at risk," she said.

Roper said a patient's right to know whether his doctor or dentist poses a possible threat is "a fundamental question in medicine, but it's not a simple question and we really can't give . . . a simplistic answer."

CDC spokeswoman Anne Sims said the hearing was called "to listen . . . to get feedback from the dental and medical professions who are affected," before officials make a decision on a new AIDS policy.

But a research director of one AIDS watchdog group speculated that CDC officials already may have made up their minds.