10 Things Your Dentist Won't Tell You

"A six-month checkup means everybody has the same risk for disease, and that doesn't make very much sense," says Douglas Benn, oral and maxillofacial radiologist and professor emeritus at the University of Florida. "If you look at the typical middle-class population, the majority are not at high risk for lots of decay and gum disease; they probably don't need to be seen every six months." A number of studies support Benn's view, finding no appreciable benefit from biannual visits for all patients. Still, a 2003 survey by the American Dental Association confirmed 53% of the U.S. population reported seeing a dentist within the past six months.

Have a conversation with your dentist about appointment frequency. You may be one of the lucky folks who don't need such frequent checkups.

2. "Those old metal fillings of yours may be leaking toxic waste."
When Rep. Diane Watson (D., Calif.) learned the mercury in her fillings could end up in her blood, she decided to have them removed. But she met with resistance from local dentists who thought it was unnecessary or worried about health risks from dislodging the fillings. Watson ignored their advice and had the work done in Mexico; she's now sponsoring a bill to phase out mercury in fillings by 2009.

Most fillings dentists use today are amalgams, a mixture of mercury, silver and tin once thought completely stable. But amalgams have been found to leak mercury vapor that can pass into the bloodstream at the rate of 10 micrograms a day — four times what the average person consumes daily in her diet. "There's no question that it's harming people," says Richard D. Fischer, a Virginia dentist, who cites studies where sheep and monkeys given amalgam fillings showed decreased kidney function and traces of mercury in other organs.

To avoid amalgams, you can request pricier resin fillings. But following Watson's lead isn't the best idea: Removal of amalgams can release a surge of mercury if the dentist isn't extremely careful, Fischer says.

3. "I care more about your smile than your teeth."
Our nation's oral health has improved tremendously in recent years. Over the past decade, tooth decay has decreased by 15% in children, and just a quarter of adults over 60 have lost all their teeth, down from one-third. Dentists attribute the improvement to such advances as fluoridation and better oral hygiene at an early age.

But healthier teeth mean less demand for traditional dentistry. Hence the booming field of cosmetics: Between 2000 and 2006, membership in the American Academy of Cosmetic Dentistry jumped 91%. Indeed, cosmetic dentistry is big business. Ronald Goldstein, cofounder of the American Academy of Esthetic Dentistry, a 100-member invitation-only organization, estimates that of the $90 billion Americans will spend this year on dental procedures, about half will go to cosmetic work. And that figure is only likely to increase.

The potential for profit is turning some dentists into pitchmen — a digital photo and special software can show you how you'd look with whitened teeth or a set of crowns. But before falling for the new you and opting for elective dental work, get a second opinion.

4. "No human being should have teeth this white."
Over the past few years, an explosion of tooth-whitening products has hit drugstore shelves, promising brilliant, made-for-TV smiles for all. But some dentists worry that the long-term effects of these chemical whiteners are unknown. "No one quite knows what's being taken off the tooth," says Reg Moncrieff, a New York City dentist. "It's possible that bleaching takes something from the tooth that you might want later."

Most over-the-counter products contain hydrogen peroxide and other bleaching agents; these unstable compounds release oxygen, which whitens the teeth over time. You'll get much faster results at a clinic, where high-intensity light acts as a catalyst when applied to far heavier concentrations of hydrogen peroxide. This route not only costs more (roughly $400), but it also exposes your mouth to more chemicals and heat, which can damage teeth. "The safest technique is the one that takes the longest," Moncrieff says.

Whatever method you choose, check with your dentist first: Certain types of discoloration don't respond well to bleaching and could leave you with a two-tone smile.

5. "When I say this won't hurt a bit, boy, do I mean it."
The ADA says modern dentistry should be painless, but the rise in time-consuming cosmetic work has some patients a little too eager to find ways of coping with hours of discomfort. To make these long procedures less daunting, dentists are using everything in their arsenal to keep patients comfortable, from old standards Valium and nitrous oxide to something called "conscious sedation." Introduced nearly a century ago to help women endure childbirth, "twilight sleep," as it's sometimes advertised, involves mixing a tranquilizer or narcotic with local anesthesia. Many patients leave the office with no memory of the procedure.

So what's the problem with avoiding pain? An increase in the use of sedatives and anesthetics means an increased risk of complications, including vomiting, fainting and prolonged recovery time. "The more you lose consciousness, the more risky it is," says ADA spokesperson Kimberly Harms. If your dentist recommends twilight sleep for your next procedure, check to see that he or someone in his office is licensed to dispense anything stronger than laughing gas.