Baby Teeth
The child's mouth contains 20 temporary teeth, called primary teeth, baby teeth, or deciduous teeth, consisting of the following teeth types:
- 4 second molars
- 4 first molars
- 4 cuspids (also called canine or eye teeth)
- 4 lateral incisors
- 4 central incisors
For each set of four teeth, two teeth are located in the upper arch (one on each side of the mouth) and two are located in the lower arch (one on each side of the mouth).
Permanent Teeth
The adult mouth contains 32 permanent teeth, consisting of the following teeth types:
- 4 third molars (also called wisdom teeth)
- 4 second molars (also called 12-year molars)
- 4 first molars (also called 6-year molars)
- 4 second bicuspids (also called second premolars)
- 4 first bicuspids (also called first premolars)
- 4 cuspids (also called canine or eye teeth)
- 4 lateral incisors
- 4 central incisors
Teeth Functions
Your teeth are used for:
- Biting and tearing. The central incisors and lateral incisors are primarily used for biting and cutting and canine teeth are primarily used for tearing food.
- Grinding and crushing. The premolars, molars, and wisdom teeth are primarily used for chewing and grinding food.
Internal Structure of Teeth
Each tooth consists of three main parts – the crown, the neck and root.
- The crown is the visible part of the tooth; it is the portion that lies above the gum tissue. A protective layer called enamel covers the crown.
- The neck is the area of the tooth between the crown and the root.
- The root is the portion of the tooth that extends through the gum and into the bone of the jaw.
Helpful Hints for Healthy Teeth
Don't believe everything you hear about what is good or bad for your pearly whites.Remember how your mother used to tell you almost everything you did was "bad for your teeth?" You may have forgotten some of her warnings. And some things she said might not be as bad as you think. Read on.
"The function of teeth is to chew food -- and to some extent, help you talk and form words," Richard H. Price, DMD, retired dentist and former faculty member of the Boston University School of Dentistry, tells WebMD. He is also a spokesman for the American Dental Association.
Teeth, Price says, are not to be used for:
- Pliers
- Coat hangers
- Ice crushers
- Potato chip bag openers
- Knot looseners
- Fork tine straighteners
- Chomping frozen candy bars full of caramel or frozen nuts
"Blenders have special blades to crush ice, for heaven's sakes," he laments.
Whiteners: Good or Bad?
Gregory L. Paskerian, DMD, a private dentist and former assistant professor at Tufts University, tells WebMD that the new whitening rage follows a continuum of products. "The strips and other over-the-counter whiteners do not damage teeth or burn gum tissue," he says. "The trays (to hold the peroxide solution) you can buy may can contain an acidic, unbuffered solution, which could damage enamel."
The best tray-type lightening, he says, is provided by the dentist, who can control the solution and timing.
"For the fastest and safest whitening," Paskerian says, "you need to get the high-intensity light systems. This light changes the molecular structure of the enamel for a time, but it goes back to normal and at a lighter shade."
He adds, though that whitening is not really a color change, but a brightness or value change.
Price says he wishes patients would concentrate more on keeping teeth healthy. "There are bleaching groupies," he says, "People who can't get enough. You can only get teeth so white."
Price also says these solutions can sometimes cause gum sensitivity, although it is usually short-lived.
Don't Overbrush Your Teeth
Price says it's hard to go wrong on paste or brush if you look for the American Dental Association (ADA) label of approval. "This means a brush is firm enough to remove plaque but not tear up gums," he says. "Choose a brush like you would a piece of silverware -- something that feels comfortable in your hand." The designation of "Soft" is preferred by most dentists.
"Don't use a brush more than three months," Price adds. "That is the limit."
If you use an electric brush, Paskerian recommends a rotary head type that you take from tooth to tooth rather than cruising across the teeth with it.
Water picks, both dentists say, can drive bacteria back up into the gums, which can lead to it lodging in other parts of the body, such as the heart. "The picks do not remove plaque," Paskerian says.
Price recommends them only for a gentle lavage before or after brushing. "Do not turn it on like a fire hose," he instructs.
Similarly, prebrush rinses, Price says, are no substitute for brushing. These methods should be used together.
Toothpaste is an abrasive, with some therapeutic additions, namely fluoride, which strengthens enamel and can shore up little breaches in it before cavities develop.
Brushing itself should be gentle, with the bristles at a 45-degree angle to the teeth, Paskerian says. Swish gently with an oval motion rather than raking the brush side to side across the teeth.
What about the ever-popular floss? Paskerian recommends the easy-glide type -- daily, of course. Since the dentin between teeth is not fully mineralized with hard enamel, don't saw away like mad. Paskerian is also skeptical of the new "paste" floss -- that means an abrasive is being pulled over the dentin, he says.
Dental Destroyers
Homemade drugs full of industrial chemicals, such as methamphetamine (meth), can ruin teeth in short order. There is even a term for the rottenness and missing teeth -- meth mouth. Muriatic acid, used to strip cement floors, is one ingredient. "These drugs also cause dry mouth, leaving the teeth open to plaque, Price says. "And the users tend to be tense and grind their teeth." (Not to mention not being too picky about brushing, flossing, and taking care of their teeth.)
But even some more respectable drugs, such as tetracycline and other full-spectrum antibotics, can cause discoloration in permanent teeth if kids take them before age 10 -- and now they are finding that adults can get color changes from some adult acne antibiotics, too, Price says.
"Discuss antibiotics with your dentist and doctor," he advises. "Sometimes, the dentist can prescribe a high-content fluoride rinse, which helps some."
Other drugs may cause dry mouth or bleeding gums.
Nicotine, of course, stains teeth, but there are also some chemicals in the burning paper that can cause discoloration, and the heat in a smoker's mouth can impede circulation and encourage gum disease.
Although it is not usually the first problem with bulimia that comes to mind, people who binge and vomit also eat away their teeth with acid.
Also -- lemon chewing is out! Both dentists mentioned this -- is there a lot of that going around?
Drinking bottled water exclusively can also be a problem. Check to see if it's fluoridated. If it doesn't say, call the company, Price advises.
And researchers have now found that obesity and insulin resistance may be linked to periodontal disease. So stick with your healthy eating to stay out of the dental chair.
What About Sugar?
What was Mom's biggest refrain about teeth? Sugar! "You will ruin those beautiful teeth!"
Sugar, both dentists say, is not the problem. How long the sugar stays on teeth is the problem. Given enough time, the bacteria in your mouth feed on the sugar and excrete damaging acid that can eat through enamel forming cavities.
So if you eat candy, brush afterward if you can.
Or chew some gum! Amazingly, even sugar gum is not a big no-no for teeth, the dentists say. It churns up lots of saliva, which carries off the sugar in short order.
Some sugarless gum, containing xylitol, is even a good decay-preventer. In fact, in California, researchers are trying to make Gummi Bears into a dental aid by making them with xylitol.
Soda, too, is not too much of a tooth problem, if you brush or drink water afterward. In fact, the diet kind contains more phosphates than can be acidic to enamel and may be a bigger threat to your choppers than regular.
Dark chocolate is not too bad for your teeth, either, Price notes.
Well, that makes it all worthwhile!
That -- and not having to crush all that ice anymore.