MACHIAS, Maine — On Monday school kids were arriving by the busload.

On Tuesday both children and adults were lined up at 8:30 a.m. in front of the Lee Pellon Event Center on Main Street in Machias, where all this week volunteers from the New York University College of Dentistry are joining dentists from throughout Maine in providing free dental care to any Washington County resident who walks through the doors.

By the last day of the clinic on Saturday, it’s expected more than 750 people will have received care, ranging from simple dental examinations and X-rays to extractions, crowns and root canals. The program has been staged here every six months for the past two years, with this week being the fourth and, from appearances Tuesday, most popular free clinic.

“In rural Washington County, dental care is an economic issue,” said Dr. Timothy Oh, a dentist who heads up the Ellsworth-based Caring Hands of Maine Dental Center. “Paying for dental care gets pushed down the priority ladder while families are trying to find ways to pay other bills.

“In rural areas, you’ll also find a culture that doesn’t value taking care of teeth, which makes programs like this an educational challenge,” he said. “That’s one of the reasons this program focuses so heavily on kids. We’re trying to break that cycle.”

Oh said many of the dental issues being addressed at the free clinic this week are related to diets filled with soda, sweets and junk food. The region’s issues with substance abuse have also created pockets of populations with severe dental problems.

“We see that, among people involved in methamphetamine use, teeth deteriorate at an exceedingly rapid rate,” Oh said. “Another contributor to poor dental hygiene is tobacco use. People who smoke are four times more likely to lose teeth. We’re dealing with a whole scenario of problems, and the answer is not drilling teeth or pulling teeth but working to create a value system that promotes dental health. We’re hoping that this week we can get people who have terrible problems with their teeth to realize the importance of having a healthy mouth.”

Staging the clinic every six months, Oh said, allows opportunities for follow-up care that is often needed to address complex problems. For one free clinic patient, his visit Tuesday was his fourth, allowing him to finally address the dental issues he has been dealing with since losing a number of teeth in an accident in Vietnam just before his discharge decades ago. Tuesday, he told clinic staff, was the first time in decades he has been willing to smile.

“We get great support from the community for this,” Oh said. “And the huge amount of appreciation from patients astounds me. For many of these NYU students who may have never been in a rural area or never been in Maine, it’s an eye-opening experience. They realize that dentistry is not about having hundreds of patients come to their posh office in a Manhattan high rise, but about meeting a need.”

U.S. Sen. Susan Collins stopped by the free clinic Tuesday afternoon and spent time visiting with volunteers and dental patients about rural America’s unmet healthcare needs.

“The national statistics say that 11 percent of people have never been to a dentist,” she said after her visit. “But, from what I’ve seen and heard here today, I suspect that number is higher in parts of Maine. I’m so impressed by the fact that they will have had 3,000 visits since this began, but it also demonstrates the extraordinary, unmet need for dental service in rural Maine.”

The clinic will continue from 8:30 a.m. to 6:30 p.m. Wednesday, May 2. Those who are staffing the program will spend Thursday touring Acadia National Park, but will be back at work from 8:30 a.m. to 5 p.m. Friday, May 4, and again from 8:30 a.m. to 1 p.m. Saturday, May 5.