A tooth is one of the hard, white things in your mouth. Teeth (plural) are used to help the mastication process by chewing food. Chew means to break up and crush food so it can be swallowed (pushed down into your stomach).
Most vertebrates and many other animals have teeth. Different animals have different kinds because they eat different foods. Some animals use teeth as a weapon.
Tooth eruption[change | change source]
Deciduous teeth or milk teeth or temporary teeth are the first set of teeth for most mammals. Humans have 20 of them. They start growing when the child is at the age of three months.
The first teeth (called "primary teeth") start to erupt (come through the skin of the jaw) when a baby is 5–10 months old. When these teeth erupt it can hurt. Babies chew on things to make the pain better. This is called teething (verb: to teethe). Most children have all 20 teeth by two or three years of age.
At age 6–7 the permanent teeth start to erupt. By the age of 11–12 most children have 28 adult teeth. The last four teeth, called 'wisdom teeth' or third molars come in by age 17–21 in most people. Some people never grow wisdom teeth. Or they may have only two instead of four.
Tooth structure[change | change source]
The outside white part of teeth is called the enamel. The enamel is made of calcium and phosphate. Under the enamel is the dentine. The dentine is softer than the hard enamel. So it is hurt more by dental decay (cavities.) Under the dentine is the pulp which has the nerves and blood vessels that go to the tooth. This is the part that causes the pain of a toothache. Cementum is outside the dentine where there is no enamel. Cementum holds the tooth to the bone of the jaw.
Types of teeth[change | change source]
Healthy teeth[change | change source]
If they are protected and kept clean, teeth should stay for a person's whole life. Many people lose their teeth early because they do not do the right things to keep teeth healthy.
Some things people can do to keep teeth healthy:
- Brush teeth after every meal and at bedtime.
- Floss after every meal (but at least once a day at bedtime.) Flossing should be done before brushing!
- Drink water with fluoride or use a fluoride mouth rinse (liquid you put in your mouth after brushing.)
- See a dentist every 6 months for a tooth exam and tooth cleaning
- Eat good foods.
- Sugars like sucrose and glucose are bad for teeth.
- Milk and cheese are good for teeth.
- Unsweetened (no sugar) chewing gum helps clean teeth, but remember to only chew the gum if you cannot brush your teeth and only for a few seconds.
- Nothing with flavor in-between meals, give your saliva the two to three hours it needs to clean teeth. The saliva can not do that if there is a continuous food film being put on to the teeth.
- Drink water, but make sure the water has a neutral pH and no added flavor. This can be checked with a simple pH tester.
Disease of teeth[change | change source]
Plaque is the soft white substance that forms on teeth when they are not cleaned. It has bacteria in it that hurt enamel. If plaque is not cleaned off, after 2 days it can become tartar. Tartar is a hard substance that forms on teeth (mostly near the gums). Tartar makes gums unhealthy and makes more bacteria grow on the teeth.
Plaque is cleaned off with a toothbrush. If tartar forms on teeth, a dentist must clean it off.
The bacteria that are on teeth eat into the enamel. Cleaning teeth, flossing teeth, eating good foods, and having a dentist take off plaque make less bacteria on teeth. If there is too much bacteria, they eat enamel faster than teeth make enamel. This makes holes in enamel called cavities. When a person gets cavities, he has the disease dental caries. Making cavities in enamel happens slowly. But once cavities go through enamel, the soft dentin is hurt much faster. If the cavity is not fixed by a dentist, it can go into the root. This permanently hurts the tooth. Once this happens the tooth must be taken out or the dentist must do a root canal (a surgery to replace the root with a chemical substance to keep the tooth in place, at times dangerous.) If the tooth is not fixed with a root canal or is not taken out, a tooth infection can happen. This infection can spread onto the face. It can even kill the person if not helped by a dentist or doctor.