Inside the dental safety net.

"Those people fortunate enough to have access to dental care and who can afford it don't understand what it's like for those who don't have access and don't have the opportunity to make choices," Marty Lieberman, Neighborcare Health's dental director, told me. "We do a pretty good job with kids—most children from low-income families come with some kind of funding; in our state, Medicaid—but we can't begin to provide all the access that's needed for dental care. It's almost like a lottery if you get in as a new patient. We just don't have enough slots." The clinics don't turn away emergency cases, but despite 21 staff dentists and longer hours than at most private practices, Neighborcare Health can take on only a fraction of the adult patients who need ongoing care.

Once an adult patient gets into the system, the wait for an appointment is one to three weeks. The Medicaid population has a higher no-show rate than insurance customers, so Neighborcare Health deliberately keeps the waiting period short. Lieberman explained: "Our patients have a lot on their minds. They're worrying about a roof over their heads, putting food on the table. ... If you let your schedule get booked up three months in advance, the chances of the patient still being able to make it or even remember it go way down."

The sliding-scale fees are low, but they still present a barrier for some patients. The clinics are paid by the "encounter," which is to say that whatever treatment is provided in a visit, the fee is the same. Neighborcare Health's lowest fee is $35, or $30 if the patient pays cash that day. My friend Dr. Gene Beck, who worked in the clinics for six years, told me, "There are days when I've taken out several teeth, which could cost a couple of thousand dollars [in a private practice situation], and the person has paid $30. And there are days when you take an X-ray, and the person pays $30." Few of the clinics' patients have dental coverage. "We don't encourage people with dental insurance to come to our clinics," Lieberman says, "because they can access care elsewhere."

In the current health care debate, policymakers tout institutions like the Mayo Clinic, where doctors are salaried rather than paid for each procedure ("fee-for-service"), a compensation method that gives doctors an incentive to provide unnecessary care. In dentistry, the Mayo Clinic's equivalents mainly serve the poor. For participating dentists, though, the trade-offs are similar. Dentists who work for Neighborcare Health earn less than private practitioners, but they also avoid the headaches of running a business. Being an employee rather than an independent operator brings benefits like predictable income and a retirement savings plan. Lieberman, who had a successful private practice in Chicago for 20 years before he moved into community dentistry, believes that he would be in the same financial situation if he had spent his whole career in public health: "When you start off in private practice, you don't make money for a long time." In many states—including Washington—dentists who work at public health clinics qualify for loan repayment and loan forgiveness programs.

Beck, who is now working in private practice, found another benefit of clinic work: leadership training. "Private practice dentists are small-business owners. They have to deal with HR, marketing, IT. They have to know about budgeting, staffing. Most dentists were science majors as undergrads, and while they might have taken an occasional business class, they're rarely prepared for the business side of things. You get a master class in business by working at a community health center."

Still, there are only 2,109 dentists employed by health clinics nationwide, compared with 164,864 in private practice. In 2007, these health centers provided dental care to less than 2 percent of all Americans on Medicaid or without dental insurance. Obviously, that's not nearly enough.

Next: Healthy Teeth for All

Click here to see a video slide show about the painful history of dentists in the movies.

Got a dentist story to tell? Become a fan of "The American Way of Dentistry" on Facebook.