1. Carnivores
   Primates
2. Mammals
   Vertebrates

Teeth aren't exclusive to a small group of animals. As a structure very similar to bone, they are found in almost all vertebrates, meaning animals with skeletons. Herbivores need teeth, too. Some plant material is very tough to chew!

1. Incisor
   Pre-incisor
2. Molar
   Premolar

The basic types of tooth are canines, incisiors, premolars and molars. Humans are omnivores, so we need teeth for tearing food. Not always meat; think of taking a bite from an apple or pear. Those are the incisors and canines. Teeth for grinding up food are called the premolars and molars.

1. Aesthetically, e.g., brown or missing teeth
   Poor nutrition
2. Chronic pain
   All of these

When they think of a reason to see the dentist, many people think of avoiding toothache and of having a nice smile. But serious dental problems can lead to a poor diet (it's hard to eat well when it hurts to chew) and even to difficulty in being understood. Teeth are involved in the way we shape consonants, so losing too many can affect speech.

1. Canal
   Cavity
2. Pulp
   Root

A tooth has one to three roots, depending upon the type. Despite this variation, you'll almost always see a tooth drawn with two roots in illustrations, advertisements for dental practices, and so on. Western movies sometimes have a traveling dentist with a giant tooth nodding on a spring above his wagon; it always has two roots.

1. An artificial replacement for a tooth's crown
   The appearance of a tooth over the gumline
2. The lowest ridge on top of the tooth
   Any of these

Crowns are sometimes called "caps." In either case, they replace the tooth's original crown, a step taken when tooth decay has gone so far that a filling isn't possible. Sometimes, like crowns worn by royalty, they are made of gold -- so the name is fitting.

1. Cilia
   Gums
2. Muscle
   Pure willpower

Gums are the pink flesh that covers up the roots of the tooth. As you likely know, receding gums are not a good thing for dental health. It can expose sensitive areas, leading to pain, and if it continues, can cause tooth loss.

1. 24
   28
2. 32
   There is no set number.

Long before actual adulthood, you'll have gotten all 32 of your permanent teeth. It's rare, but some people have extra teeth. As we learned in 2018's "Bohemian Rhapsody," Freddie Mercury had four extra teeth in the back of his mouth, and credited them for his vocal ability.

1. Axon
   Crown
2. Neck
   Pulp chamber

Though we don't often hear about the "neck" of a tooth, it is the part just below the crown. "Axons," though, are not found in teeth -- they're a part of neurons. Well, okay -- to the extent that your have some nerves inside your teeth, yes, you have axons ... but you won't find them on any diagram of the tooth.

1. 16
   20
2. 24
   32

Humans almost always have 20 teeth in early childhood. They begin losing these milk teeth -- also known as "baby teeth" or "primary teeth" at age five or six, as the jaw grows and has room for the larger, adult set. It's traditional in America for children to leave a baby tooth under the pillow for the "Tooth Fairy," aka the parent or guardian who leaves a small amount of money in exchange.

1. A cavity
   An extra tooth
2. Tooth loss
   Receding gums

"Caries" is the medical term for what we patients, especially sugar lovers, call a cavity. Caries is mainly caused by an acidic environment in the mouth over too long a period of time. What causes this acidity? Usually the fermentation of carbohydrates. Just when you thought the case against carbs was damning enough!

1. Enamel
   Formica
2. Mucosa
   Myelin

You might use, or have heard advertisements for, enamel-protecting toothpaste. People sometimes blame excess brushing for enamel loss, but it's a minor concern compared to exposure to dietary acids, like sugars. The sugars can be refined or natural; fruit doesn't get a pass.

1. Breaching
   Mastication
2. Odontoblasty
   Teething

"Teething" is the informal name for this process, the one which parents most commonly use. We're not being dramatic when we use the word "eruption" for the process. "Tooth eruption" is the one you'll find in dental textbooks and in other professional contexts.

1. Enamel
   Gums
2. Root
   Cavity

You might have heard of gingivitis, or inflammation of the gums. The singular of "gingivae" is "gingiva," but we imagine that it's rarely used: How can you really tell where one gum leaves off and the other one starts? Also, inflammation of the gums is unlikely to affect just one; there are no natural barriers.

1. Erythrocyte
   Pectin
2. Plaque
   Scrim

We didn't include "tartar" as an answer option for this one, because it would have been too misleading. They're similar; in fact, plaque is a precursor to tartar. The difference is, tartar is solid and easily seen; part of the job of a dental hygienist is gently chipping it off teeth.

1. Bromine
   Lactic Acid
2. Pulp
   Paste

The name "pulp" makes it sound as though the stuff is biologically inert -- think of wood pulp, which is just crushed-up wood fibers that paper can be made from. But dental pulp is very biologically active. It contains blood vessels, nerve endings, and immune cells.

1. True
2. False

This one's true! The roots of your teeth do not float in gum tissue or muscle, but actually grow into the jaw bone. When archaeologists find jaw bones of early humans, they frequently have most of the teeth still attached.

1. Yes!
   Nope!
2. Dentin is; cementum isn't.
   Cementum is; dentin isn't.

Cementum covers the root of the tooth, under the gum layer, in the same way that enamel does the exposed area. "Dentin" is the substance that comes between enamel and the pulp chamber, or cementum and the pulp chamber.

1. Every four months
   Every six months
2. Yearly
   Only when you're having pain or discomfort

A good dentist will want to see you semi-annually. That's every six months, for those of you (and there's a lot!) confused by the difference between "semI" and "bi." "Biannually" is every two years. We know this quiz is on teeth, but it's never a bad time for a quick vocabulary lesson. This one can save you from turning up a year-and-a-half late for an appointment!

1. Dentures
   Mandibles
2. Geriatric teeth
   They're just called "prosthetic teeth"

If you've watched TV programming with an elderly demographic (we're thinking of the old "Lawrence Welk Show" and similar), you've probably seen advertisements for denture cleaning products. Dentures, however, are becoming less common as dentistry develops more sophisticated ways to preserve existing teeth.

1. Near the front
   Near the back
2. In the upper jaw
   In the lower jaw

We tend to think only of our lower jaw, the part that moves, as the "jaw." But we have an upper jaw, the maxilla, and a lower jaw, the mandible. This gives us a basic distinction between teeth: Upper ones are 'maxillary," lower ones are "mandibular."

1. Bridge
   Join
2. Plate
   Semi-plate

Bridges are becoming more common than full sets of dentures, which is one of the improvements in dental treatment in recent decades. Bridges work out best in patients with good diets and good oral hygiene. Where these things are lacking, a dentist might not recommend a bridge, as the patient likely won't be able to maintain it.

1. Ambergris
   Gold
2. Porcelain
   Amalgam

Ambergris is a substance that sperm whales produce. It's a kind of wax which, when dried, is used as a fixative in perfumes. Whales have been hunted for it for centuries. However, it has no use in dentistry (for which we're pretty glad!)

1. Dental sealant
   Inlay
2. Post
   Root canal

Inlays, onlays and overlays are all replacements for lost tooth material. Like crowns, they are cast outside the tooth, harden, and then are sealed in place. However, unlike crowns, they do not replace the entire top, or visible part, of the tooth.

1. Fricative
   Labial
2. Oral
   Gastrointestinal

"Oral" is an adjective meaning "of or about the mouth." (We'll pause here so that the teenage boys among us, whether literally or just psychologically adolescent, can snicker). Taking care of your teeth can keep your whole mouth healthy.

1. Monthly
   Every three to four months
2. Semi-annually
   Yearly

Another answer for this might have been "whenever the bristles become spread out and frazzled-looking." However, if this is happening every month or six weeks, it's quite possible that you're overbrushing. This can wear down enamel and create sensitive spots.

1. Nitrogen
   Fluoride
2. Hydrogen
   Vitamin D

Fluoride is a weak base, meaning that it is alkaline, and thus neutralizes acids in the mouth. Any good toothpaste will contain fluoride. If you let a well-meaning but "crunchy" friend sell you on non-fluoride alternative, you're likely to pay the price in tooth decay and dental bills.

1. Yes, it is.
   No, it has to be added.
2. It is, but more has to be added to get to therapeutic levels.

Fluoride naturally occurs in small amounts in rainwater. But governments including Canada, the U.S., and Mexico add fluoride to water. The American Dental Association has estimated that every $1 spent on water fluoridation saves $38 in dental-care costs.

1. Blood
   Nasal mucus
2. Saliva
   Sweat

As simple "location, location, location" might suggest, it's saliva that neutralizes acid in the the mouth and protects teeth from decay. We're really glad the answer wasn't blood, sweat or nasal mucus. The potential method of its application to teeth would be, uh, frankly disturbing.

1. Daily
   Twice a day
2. Three times a day
   After any contact with food

Dentists recommend brushing twice a day. If you're concerned about your consumption of sugary food between those times, a simple solution is to drink water with your meal or snack. It's not really the fluoride content of the water that's important, but simply that it washes away most of the sugar residue, leaving little to cling to your teeth.

1. Daily
   Twice a day
2. Every two to three days
   Weekly

Many people find flossing to be a much bigger hassle than brushing, which is odd, because it's really not that much more effort. One hygienist's tip: Floss in the shower, while enjoying an extra minute or two under the hot water. It make the activity more pleasant, and ensures you'll probably do it at least every other day.

1. $3 million
   $11 million
2. $1 billion
   $27 billion

We are not making this up! It comes from the Journal of Dental Research, which looked at lost productivity and the resulting economic loss. It's important to remember that this estimate is global, including the developing world, where water is unfluoridated and fewer people can afford to see dentists for preventive care.

1. Acid reflux
   Everyday chewing
2. Tooth grinding
   All of these

Acid reflux is the cause that is most similar to sugar consumption, except that the acids involved are gastric acids from the stomach. Chewing and tooth grinding are simple mechanical causes of breakdown; the latter sometimes happens in a person's sleep and is hard, for that reason, to avoid.

1. True
2. False

Amalgam is a substance used for fillings. It often contains mercury, silver, tin and copper. The FDA and the American Dental Association Health are in agreement that there is no evidence that mercury in fillings causes adverse health effects. Rather, calls to ban mercury in amalgam seem to be based in the human need to find exotic causes for simple but hard problems -- in America's case, the health woes that come from sedentary lifestyles and dietary excess.

1. Flossing
   Grinding of teeth
2. Brushing the tongue
   Drilling away decayed tooth material

"Bruxism" sounds related to "brushing," but it's the way dentists refer to clenching or grinding the teeth. We probably don't have to tell you that it's usually psychological in nature, although there's a suspected genetic factor, as well. Bruxism can happen both in sleeping and waking hours.

1. Gerald Ford
   Andrew Jackson
2. Martin Van Buren
   George Washington

Washington had lost all his teeth by the time he became our first president; the exact reason why isn't known. But during his term, Washington dealt with chronic pain and used opiates to relieve it. Historians have a generally favorable opinion of his presidency, so it's hard not to wonder how much more effective he would have been without these issues.