Does your child have a lacy white pattern on his or her teeth, or noticeable mottling and spots? If so, it could be a condition called enamel fluorosis.

The culprit? Something you always thought was a good thing: fluoride.

Fluorosis happens when children get too much fluoride while their teeth are developing. According to the Centers for Disease Control and Prevention, that usually means up to age 6.

This excess fluoride affects the enamel surface of the teeth, leaving them with anything from lacy white markings or small spots to more severe pitting and staining. And while it’s more of a cosmetic problem than anything else, it is a growing issue in American dental chairs.

The CDC estimates that the first study of enamel fluorosis back in the 1930s and ’40s (right before fluoride was added to many drinking water supplies) showed that anywhere from 12 to 15 percent of children had fluorosis, mainly from natural supplies in the water. By 1987, the last time a nationwide study was done, between 22 and 23 percent of children had fluorosis. Some experts believe today’s number to be much higher.

At Aspen Dental Associates in Newburgh, Dr. Matthew Yarnis says he’s not seeing a sharp increase in cases of fluorosis come through his office, but he is certainly aware of the concern.

“It’s a known entity,” Yarnis says, “the mottling, the irregular discoloration. They’re dosing the water, plus toothpaste, which many are swallowing, plus putting fluoride in vitamins. Some people get a little over the top.”

HERE’S HOW EASY IT IS to go over the top. In addition to brushing his teeth with fluoride toothpaste, rinsing with a fluoride rinse, taking vitamins with fluoride and receiving fluoride treatments from the dentist – not to mention likely drinking fluoridated water (nearly 73 percent of New York’s water supply is fluoridated) – your child might be getting fluoride in places you never even dreamed of.

In fact, a study by the U.S. Department of Agriculture found fluoride in a wide variety of packaged foods including soda, cookies and baby food.

The use of fluoride, particularly in public water supplies, is not without controversy. Anti-fluoride activists have campaigned against it throughout the 60 years it’s been used in water supplies. They say it can cause health problems and is tied to higher lead levels in water.

Recent research indicates it could be linked to bone cancer in boys and increased risk of osteoporosis in women. Just this year, 11 unions representing workers at the U.S. Environmental Protection Agency called on the EPA to name fluoride a carcinogen. They also called for a nationwide moratorium on fluoridation of water.

The CDC, however, calls fluoride one of the greatest public health achievements of the 20th century. The American Dental Association lauds it as the safest and most effective method available to prevent tooth decay.

SO WHAT, THEN, is the average parent to do?

First, don’t let your kids eat a whole tube of toothpaste, Yarnis warns. Follow the CDC guidelines and have children under the age of 6 use a pea-sized amount of toothpaste on their brush (or consider one of the newer child-strength toothpastes).

Monitor kids as they brush, says Sandy Gulak, dental hygienist with Dr. Joseph Gulak’s Middletown office. “Make sure they spit it all out.” Gulak suggests having the fluoride level in your water checked as well.

If your child’s teeth already show signs of fluorosis, there are a few things to keep in mind.

On the up side, Yarnis says that teeth with fluorosis are likely more resistant to decay. On the down side, the discoloration can lead some kids to feeling self-conscious about their teeth and can be costly to get rid of.

Dr. Michael Lee of the Goshen Dental Center, who sees 15 to 20 cases of fluorosis a year, says it’s usually younger people who feel self-conscious about the stains.

“Their friends probably don’t have it as much,” he says, “and the younger population has better-looking teeth overall.”

To get teeth with fluorosis better-looking, Lee says polishing with a pumice stone can work in some milder cases. The treatment, which runs about $150, is usually only used on the six most visible teeth. Composite bonding can run $200-$250 a tooth, with veneers running from $1,000 to $2,000 a tooth.