Robin Benjamin was devastated when she chipped a tooth two weeks ago, having had no medical or dental insurance since she cut back on work to attend nursing school.

Then the 48-year-old South Sider heard about the Catholic Charities Free Health Center, which had just opened Downtown. A dentist fixed her broken tooth, lectured her on flossing and saw that she came back to extract two crumbling molars.

"They're going to get it before it hurts. Tooth pain is the worst pain ever," Ms. Benjamin said as she waited for her mouth to go numb. She wasn't frightened, she said, because the dentist had taken such good care of her last time.

The health center has been inundated with 1,000 calls since it opened Nov. 5. About half the callers have at least begun the process of determining their financial eligibility. In the first two weeks about 75 patients saw a doctor or dentist.

The services are free.

"No money ever changes hands," said Diane Redington, the administrator.

It does not serve the poorest, who qualify for Medicaid; or the elderly, who have Medicare; or those under 18, who can get CHIP insurance. The Catholic Charities Health Center is for working people, ages 18-64, with no insurance. Patients can earn up to twice the federal poverty guidelines, meaning $20,420 for a single person or $41,300 for a family of four.

"We want people who have nothing, no insurance," Ms. Redington said.

Nationally, 47 million people, or 15 percent of the population, fit that description. Catholic Charities estimates that 70,000 of them live within a 10-mile radius of its headquarters at Liberty Avenue and Ninth Street, where the clinic is.

One example was a former school crossing guard whose health forced her to retire early, but who could afford neither health insurance nor her expensive medications. The clinic helped her get pills at a much lower cost.

One man arrived with such skyrocketing blood pressure that he was in danger of a stroke. He was so afraid of medical bills that the staff had to plead long and hard to be permitted to send him to a hospital.

Because his job offered no sick days, "he also missed getting paid that day because he was in the hospital," Ms. Redington said.

The clinic staff was surprised at some of the people who have no health insurance, including many part-time nurses and part-time postal workers.

"Everyone has a different story," Ms. Redington said. "Some made poor choices. Some made good choices and had bad luck. It's not for us to judge."

The clinic's goal is to offer first-class service in a first-class setting. It got a boost from the building itself, which Catholic Charities has occupied since 1993. Built long ago to house the Federal Reserve Bank, it retains an air of elegance. Patients walk on gleaming, white marble floors. Using a state grant, the clinic bought all new equipment and uses a state-of-the-art electronic medical records system.

"We wanted the best for our patients, and we got it," Ms. Redington said.

Ms. Redington is a nurse who spent years working for insurance companies. She also did volunteer relief work in Haiti, El Salvador and Belize.

"This was the perfect place for me to be," she said. "The staff here has all done international relief work, but felt there was a need in our own community."

Dental work has proved the most popular service, since it isn't offered at the city's other Christian health centers for the poor. Calls have run at a ratio of 3-to-1 for dental over medical care.

Dental care is a medical issue, said Dr. Ed Kelly, the clinic's medical director. Not only are infected teeth painful, but they aggravate conditions such as diabetes and hypertension.

The Catholic Diocese of Pittsburgh announced plans for the free clinic in March 2003, with then-Bishop Donald Wuerl giving the first $250,000. Two $1 million grants from the state ensured the project's future. But along the way Pittsburgh changed bishops and lost two executive directors of Catholic Charities.

"Whatever else was going on, the diocese was completely committed to getting the clinic up and running," Ms. Redington said.

The first year's operating budget is $1 million, but that includes start-up costs. To continue the same level of service is expected to cost about $600,000 per year, she said.

Patients are seen Monday, Tuesday and Thursday from 9 a.m. to 4 p.m. The office is open Wednesday and Friday to assist applicants with paperwork.

The plan is to offer care five days a week by early 2008, but there has been a lag in clearing volunteers through a federal program that allows retired health professionals to do volunteer work without malpractice insurance. About 100 have volunteered, including 25 physicians, six dentists and more than 30 nurses, but their federal applications are in process.

The chief recruiter is Dr. Kelly, a retired orthopedic surgeon from St. John Capistran parish in Upper St. Clair, who formerly practiced at St. Clair and Mercy hospitals. At Mercy he often treated uninsured patients, including homeless people from Operation Safety Net, in which doctors and nurses took medical care to the streets.

When Dr. Kelly retired in 2003, he volunteered for Operation Safety Net, helping staff its medical van and a shelter that opens when the temperature drops below 20 degrees.

"I was made very well aware of the needs that exist throughout the Western Pennsylvania area," he said.

He had served on the board of Catholic Charities for 10 years, and was recruited for the clinic project. When the need arose for a medical director, he volunteered.

He is the center's chief recruiter of volunteers and free or discounted medical supplies and services.

"He builds relationships with the community," Ms. Redington said.

The effort to open the clinic "really picked up steam when Dr. Kelly came on board. Prior to that, there was no champion who knew how to do it. He volunteered, and he's never stopped."

He is not among the four paid staff, which includes Ms. Redington, a dental assistant, a nurse practitioner who serves as clinical coordinator and an office coordinator.

Because the clinic is in Catholic Charities headquarters, it's a one-stop shop for those who also need social services.

One patient who was being issued instructions after an office visit, burst into tears because she felt overwhelmed by all the other problems she faced. The staff called upstairs to the counseling offices, and a social worker came down immediately to see her.

"When she came back later for a dental appointment, she was smiling," Ms. Redington said.

For Dr. Kelly, the work is its own reward.

"There is such a huge need. I feel very invigorated by the opportunity to respond," he said. "You have to reach out to your fellow human being."