Most of us have a dentist. We go twice a year for cleanings. Once a year for x-rays. But for the state’s 800,000 low-income residents, finding a dentist is not so easy.

Harriotte Hurie Ranvig knows this firsthand.

"I had serious problems with a molar," she said.

Hurie Ranvig is blind, and she’s on MassHealth, the state’s Medicaid program.

"I needed a root canal and a crown, which together were upward of $3,000," she said. "And MassHealth didn’t cover that."

So Hurie Ranvig negotiated a payment plan with her family dentist -- it took her more than four years to pay off. And after all that, there were complications to the root canal and she had to have the tooth extracted.

"It got complicated because in reality, my dentist belonged to a group of dentists in Davis Square, and about five years ago those dentists decided that all their MassHealth recipients should go out to a clinic in Stoneham," she said.

The dentists decided to no longer accept MassHealth from patients older than 21 at their Somerville location. Hurie Ranvig would have to take two buses to get to their other clinic in Stoneham. Because she is blind, her dentist continued to treat her in Somerville.

"He still takes me, but my daughter, she goes to the one in Stoneham," she said.

The choice made by that group of dentists is not unique. In fact, most dentists in Massachusetts -- and the nation --  do not take Medicaid.

"There’s a different professional ethic within dentistry about serving the poor," said Nancy Turnbull, a health policy lecturer at the Harvard School for Public Health. "That’s not to say that there aren’t lots and lots of dentists who do feel an ethical and professional obligation to participate in the Medicaid program and provide care to the poor. My experience and observation is that that is less a part of the dental profession."

Turnbull says Medicaid is not financially as important to dentists as it is for other health care providers.

"There’s been diversification of services that many dentists provide and particularly cosmetic kinds of procedures -- teeth whitening --  there’s been an explosion of providing braces to adults," she said.

The explosion of cosmetic services like these can lead to a lucrative practice, especially for dentists whose patients are able to pay out-of-pocket.

"We have overheads, we have employees, we have rents, we have taxes, we have ever-increasing regulations we have to deal with," said Michael Wasserman, president of the Massachusetts Dental Society, which represents the majority of dentists in the state. "So people make their economic choices."

Only 35 percent of the society’s members accept Medicaid.

Wasserman blames it on MassHealth reimbursement rates, which he says are unreasonably low, and dental benefits that are limited for low-income adults.

"It is a deterrent," he said. "People are going to come into their office. They’re not going to be able to do very much for them. With the little they can do, the reimbursement is not very good. So it’s a turnoff in terms of providing the care."

Wasserman accepts MassHealth at his practice in Pittsfield. He says that several years ago lawmakers made it possible for dentists to limit the number of Medicaid patients they accepted. This was done to calm a fear among dentists that if they accepted MassHealth, they would be flooded with low-income patients.

"So you get a certain number of patients and you say, I have enough," he said. "I don’t want to see anymore for now. You can basically what they call close the panel. If you want you could open it but you are allowed to limit the number of patients that you see."

Wasserman said this was a good incentive that helped increase the number of providers in the Massachusetts Dental Society who accept MassHealth patients. Still, access to dental care remains a major problem for the poor.

"There’s a tremendous need out there in the population," he said.

William Horgan, dental director at the Joseph Smith Community Health Center in Waltham and Allston, said community health centers are often the only reliable option for low-income patients to get dental care.

"We have a waiting list that’s a year and a half long," Horgan said.

Patients waiting on that list can eventually get dental services at a reduced rate, and pay on a sliding scale, based on their income. And if the patients are uninsured or underinsured, the center can bill the Health Safety Net – a reimbursement fund designed specifically for community health centers and hospitals. While the Health Safety Net does not cover all dental services, it does reimburse for many of the procedures MassHealth does not cover, including root canals, crowns and bridges for some teeth, as well as partial and full dentures.

But community health centers are maxed out with dental patients. Between its two locations, the Smith Community Health Center has seven dental chairs, but that’s not enough for the 800 patients they have on their waiting list. They recently received grant support for a new building, which will double the size of their dental clinics.

"Everybody in here is very excited about that because nobody feels the pressure more than we do," he said. "How would you like to tell someone that needed a filling or needed dentures, 'Well, I’m sorry, you’re going to have to wait six months before we can do it.' It’s a terrible thing you have to do day in and day out."

Horgan says that while access to care would be better for poor people if more dentists took Medicaid, it wouldn’t solve the problem -- not unless reimbursements are improved, and MassHealth dental coverage becomes more comprehensive.

"Society has to value this care more than it currently does," he said. "I think that’s really the bottom line."