1. gnashing
   bruxism
2. dentaphilia

Bruxism is the medical term for teeth grinding, and the people who grind their teeth are known as "bruxers."

1. 1 to 2 percent
   10 to 15 percent
2. 40 to 50 percent

Ten to 15 percent of adult Americans grind their teeth -- that's a total of about 47 million people!

1. 20 percent
   30 percent
2. 50 percent

Nearly half! It is thought to be a result of teething.

1. 20 percent
   30 percent
2. 50 percent

About 30 percent, and once children have their adult teeth, around the age of 12, the percentage drops even more significantly.

1. 5 percent
   45 percent
2. 65 percent

65 percent! Go on to the next question to find out what might be the cause.

1. stress
   high dentist bills
2. gingivitis

Stress seems to be the root cause for most adults. In children, however, bruxism isn't thought to be caused by stress. It's considered a habit or self-soothing behavior.

1. antidepressant medication
   misaligned bite
2. MSG

Certain antidepressants and a misaligned bite, known as a malocclusion, can contribute to teeth grinding, but as far as we know, MSG is not a factor.

1. Twice as fast
   Five times as fast
2. 10 times as fast

Grinding can exert up to 250 pounds of pressure on teeth, as opposed to the usual 20 to 40 pounds from eating, so it's no surprise that bruxers erode the enamel on their teeth 10 times faster than non-grinders.

1. 10 minutes
   25 minutes
2. 40 minutes

40 minutes. Nighttime grinding is particularly hard to diagnose without a sleep partner, so if you suspect you might be bruxing in your sleep, it's best to see your dentist so he or she can examine the wear on your teeth.

1. sensitive teeth
   discolored tongue
2. dark spots in your vision

Sensitive teeth is a common symptom of teeth grinding. Others include inflamed gums, headaches and ear aches, and TMJ problems.

1. frontalis
   masseter
2. orbicularis oris

The masseter muscle is involved with opening and closing the jaw and can become painful and irritated from the grinding of the teeth.

1. playing tennis
   meditation
2. both of the above

Anything that relaxes the body, like sports or meditation, can help reduce stress and thereby, grinding.

1. metal harnesses
   Botox injections
2. eating lemons

Botox injections are thought to relax the jaw muscles. Some patients have had success, but there is little scientific evidence to back this treatment up. At best, the results are temporary.

1. mustard
   warm washcloth
2. duct tape

A warm washcloth can help relax the jaw muscles and keep the teeth from clenching.

1. dentists
   string beans
2. chewing gum

Bruxers should avoid chewing gum, or on anything hard -- including the ends of pens and pencils.

1. splint
   mouth guard
2. harness

A splint helps prevent grinding by keeping the teeth separated. Mouth guards protect the teeth, but do not necessarily keep you from grinding.

1. bad sitcoms
   alcohol
2. airplane flights

Alcohol has been implicated in teeth grinding (although it might help with the bad sitcoms).

1. true
2. false

More women than men are bruxers. The fairer sex is also much more likely to grind her teeth if a close relative does, as bruxism is considered hereditary.

1. flying
   hockey
2. smoking

Smokers are much more likely to grind their teeth than non-smokers.

1. 20 to 40
   40 to 50
2. 50 to 70

Although stress levels are probably a better indicator than age, 20 to 40 is the most common age for teeth grinding.