If you plan to retire soon, consider a visit to the dentist before your dental insurance disappears.

Retirees transitioning to Medicare are often surprised to learn that the program does not cover routine dental care or more complex procedures.

Overall, 40 percent of the 65-plus population has some form of dental benefit, according to the National Association of Dental Plans. For seniors who use Medicare Advantage managed care plans, about half offer very limited coverage for cleanings and exams.

A small percentage of seniors have dental insurance from a former employer, and Medicaid covers dental care for low-income residents in some states, although benefits vary. Some buy individual commercial plans or have coverage through an association such as AARP.

But most seniors just pay for dental care out of pocket. The mean expense for Americans age 65 and older was $870 in 2012, according to the Agency for Healthcare Research and Quality, a research arm of the U.S. Department of Health and Human Services.

The costs can be far higher for more complex procedures. The average cost of a crown in New York City is $2,500; a periodontal procedure in Los Angeles costs $1,700, according to Fairhealthconsumer.org, which tracks prices of healthcare and health insurance.

Those numbers help explain why 34 percent of seniors had not seen a dentist in two years in 2010, and 22 percent had gone without care for the past five years, according to the Kaiser Family Foundation (KFF).

Medicare celebrates its 50th anniversary later this month, and adding basic dental coverage is on the wish list of many health policy experts reflecting on the program's future.

Research shows clear links between poor oral health, diabetes and heart disease. One out of four Medicare beneficiaries no longer have any of their natural teeth, according to KFF; that can cause other health problems, such as nutritional deficiencies and ­problems with speech.

Pricing options

Premiums for private plans are reasonable — PPO plans cost about $15 per month. But individual coverage is not as robust as group plans; waiting periods and lower caps are typical.

Dental insurers have been negotiating with the federal government to offer individual stand-alone dental plans through the Affordable Care Act insurance exchanges, and expanded offerings could start showing up in 2016 or 2017.

Dental plans are available on many exchanges now, but they can only be purchased along with general health insurance. That effectively cuts out seniors, who are ­covered by Medicare.

Consumer advocates are pushing for Medicare to pay for dental care made necessary by other procedures that the program does cover.

"Medicare covers what happens to the patient's eyes even though it doesn't provide routine eye care — but there's no coverage for this type of extreme dental care, and people are ending up in the hospital with infections," says Margaret Murphy, an associate director with the Center for Medicare Advocacy (CMA).

The litigation has not been successful so far, but CMA has not given up. "We're trying to figure out where to go with it next," Murphy says.

Mark Miller is a Reuters columnist.