One in three Americans can't afford to see the dentist.

More than 100 million Americans do not go to the dentist for checkups and cleanings because of the cost, according to PBS FRONTLINE and the Center for Public Integrity. As a result, many go broke trying to afford dental care or suffer from extreme pain. Some die.

The next generation of Americans already is suffering. Nearly 5 million American children, or one in 16, did not get regular dental checkups in 2008 because their families could not afford it, according to an Institute of Medicine report released last year.

Some corporate dental firms are profiting from Americans that cannot afford dental care, according to an investigative article by the Center for Public Integrity and FRONTLINE published on Tuesday. These firms are dentistry's version of payday lenders, targeting low-income consumers that are ignored by mainstream dentists and charging excessive rates. One of these companies, Aspen Dental, which is owned by a private equity firm, gave 87-year-old Theresa Ferritto a credit card to pay thousands of dollars she owed after getting two teeth pulled, according to CPI.

Going without dental care can ruin lives. Louis Morris, 33, of Philadelphia, found out on Saturday while seeing a dentist for the first time in 15 years at a volunteer clinic that his gum infection had worn away at his jawbone, could spread to other parts of his body and wipe out all of his teeth, the Philadelphia Inquirer reports. Morris already had lost several of his teeth.

Forgoing dental care sometimes is fatal. Kyle Willis, a 24-year-old father from Cincinnati, died from a tooth infection last year because he could not afford antibiotics or to get the tooth pulled out, according to ABC News. He was unemployed and had no health insurance. The infection spread, caused his brain to swell and then killed him.

The FRONTLINE investigation of the dental coverage gap airs on Tuesday night on PBS at 10 p.m. EDT. It can be watched online here, starting at 10 p.m. on Tuesday.

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