When the 5-year-old boy opened wide for dentist Lindsey Robinson in April, she found cavities in the back corners of his mouth. But his parents, who had no insurance, didn't bring him back for fillings.

The boy returned in September with a toothache. Untreated, one cavity ''got into the nerve and developed an abscess,'' says Robinson, who practices in Grass Valley, Calif. She had to remove the tooth. "The parents felt horrible putting it off,'' she says.

This recession has led many adults to postpone trips to the dentist, both for themselves and their children. "In tough economic times, you're concerned about your job and your expenses,'' says Bill Prentice, director of the American Dental Association's Washington office. "People are putting off dental care. Patients aren't coming back for checkups as they should.''

During the ferocious debate on health reform, meanwhile, dental care has largely been shunted to the sidelines. It's treated as separate -- and unequal-- to general medical care, says Oral Health America, an advocacy and education organization that has called for dental coverage for all Americans.

The American Dental Association has also pushed for inclusion of dental care in reform legislation. In addition, the group seeks better pay for dentists who treat patients covered by Medicaid, the government insurance program for the poor and disabled. Currently, many state Medicaid programs don't cover dentists' costs of seeing these patients.

California, mired in a budget crisis, has even removed dental coverage for adults on Medicaid, Robinson notes.

Dental care represents about 5% of overall health care spending. But the out-of-pocket expenses can add up, especially for the more than 100 million Americans who have no dental coverage -- more than twice the number who lack health insurance. Kids without dental insurance are much more likely to have no regular dental care than those with coverage. And untreated tooth decay in children can cause pain, difficulty concentrating on learning, loss of school days, and difficulty in eating and sleeping. Tooth decay is the most common chronic disease of children, says the Centers for Disease Control and Prevention.

Untreated tooth problems afflict millions of adults as well. Adult dental procedures typically are much less expensive than those in general medical care, but some still can run into the thousands of dollars, which leads many to forgo treatment. In 2005, 25 million adults did not receive dental care because they couldn't afford it, according to a report by Delta Dental Plans Association.

Families who have private dental insurance generally get at least some coverage for cleanings, fillings and X-rays, as well as twice-a-year checkups.

People without coverage can get short-term relief with lower-cost care at a community health center, a county health department, or a clinic at a dental school.General dentists in private practice averaged $206,000 in income in 2007, according to the American Dental Association, though the group says the economic downturn has squeezed that pay.

Robinson, a pediatric dentist, works in a rural area in Northern California where the recession has struck hard. Like other dentists, Robinson says she's flexible on payments if a family can't immediately pay the entire cost of a visit. "I'm certainly willing to work with people,'' Robinson says.

About 20% of her pediatric patients have no coverage at all, she says.

"There are so many kids with giant holes in their mouth,'' she says. ''They have advanced disease. Many need a great deal of treatment.''

Robinson sees the reform debate in Washington as vitally important as millions more Americans may gain health insurance. Preventive dental care and treatment should be covered for those newly insured people, she says.

Like other oral health advocates, she wants to put teeth in health care reform. "It's important that dentistry has a seat at the table,'' Robinson says.